[v16,3/4] pwm: Add support for RZ/G2L GPT

RZ/G2L General PWM Timer (GPT) composed of 8 channels with 32-bit timer
(GPT32E). It supports the following functions
 * 32 bits × 8 channels
 * Up-counting or down-counting (saw waves) or up/down-counting
   (triangle waves) for each counter.
 * Clock sources independently selectable for each channel
 * Two I/O pins per channel
 * Two output compare/input capture registers per channel
 * For the two output compare/input capture registers of each channel,
   four registers are provided as buffer registers and are capable of
   operating as comparison registers when buffering is not in use.
 * In output compare operation, buffer switching can be at crests or
   troughs, enabling the generation of laterally asymmetric PWM waveforms.
 * Registers for setting up frame cycles in each channel (with capability
   for generating interrupts at overflow or underflow)
 * Generation of dead times in PWM operation
 * Synchronous starting, stopping and clearing counters for arbitrary
   channels
 * Starting, stopping, clearing and up/down counters in response to input
   level comparison
 * Starting, clearing, stopping and up/down counters in response to a
   maximum of four external triggers
 * Output pin disable function by dead time error and detected
   short-circuits between output pins
 * A/D converter start triggers can be generated (GPT32E0 to GPT32E3)
 * Enables the noise filter for input capture and external trigger
   operation

Add basic pwm support for RZ/G2L GPT driver by creating separate
logical channels for each IOs.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v15->v16:
* Replaced the macro DIV_ROUND_UP_ULL->DIV64_U64_ROUND_UP
* Added DIV_ROUND_UP in rzg2l_gpt_calculate_pv_or_dc() to avoid loss of
  precision.
* Replaced min->min_t() in rzg2l_gpt_calculate_pv_or_dc().
* Added a comment for rzg2l_gpt_config()
* Replaced mul_u64_u32_div()->mul_u64_u64_div_u64() in rzg2l_gpt_config()
* Fixed the logical condition related to counter stop in
  rzg2l_gpt_config().
* Dropped pm_runtime_resume_*() from rzg2l_gpt_config() as it is managed
  by rzg2l_gpt_apply().
* Moved pm_runtime_resume_*() from rzg2l_gpt_{en,dis}able() to
  rzg2l_gpt_apply().
v14->v15:
* Added enable_count and ch_en_bits variables to struct rzg2l_gpt_chip
  based on feedback for pwm_mtu3 driver.
* Updated copyright header and commit description by replacing "This patch
  adds"-> "Add"
* Replaced macro RZG2L_GET_CH_INDEX->RZG2L_GET_CH and replaced ch_index->ch
  throughout
* rzg2l_gpt_{enable,disable}() enables/disables PWM based on the
  enable_count.
* Replaced pm_runtime_get_sync->pm_runtime_resume_and_get and propogated
  the error in rzg2l_gpt_get_state() and rzg2l_gpt_config()
* Reduced variable scope in rzg2l_gpt_get_state() by moving most of variables
  inside the if statement.
* Updated rzg2l_gpt_get_state() by moving duty > period check
  inside the top if block.
* Added helper functions rzg2l_gpt_calculate_pv_or_dc()to simplify config. 
  Also Improved the logic in rzg2l_gpt_calculate_pv_or_dc() by using
  min(period_or_duty_cycle >> (2 * prescale), (u64)U32_MAX);
* Updated rzg2l_gpt_get_state() by moving duty > period check
  inside the top if block.
* Simplified rzg2l_gpt_config() for updating registers
* Dropped pm_runtime_get_sync() and used bitmap variable "ch_en_bits"
  to make balanced PM usage count in rzg2l_gpt_reset_assert_pm_disable()
  For case were unbind is called before apply where pwm is enabled by
  bootloader.
* Added error check for clk_rate_exclusive_get() and clk_get_rate() in
  probe().
* Dropped prescale from struct rzg2l_gpt_chip.
* Replaced of_match_ptr(rzg2l_gpt_of_table)->rzg2l_gpt_of_table in struct
  rzg2l_gpt_driver
v13->v14:
 * Removed parenthesis for RZG2L_MAX_HW_CHANNELS and RZG2L_CHANNELS_PER_IO
 * Removed duty_cycle variable from struct rzg2l_gpt_chip and added comment
   for cache for prescale variable.
 * Fixed a bug in rzg2l_gpt_cntr_need_stop().
 * Reordered rzg2l_gpt_config() just above apply()
 * Replaced pwm_is_enabled()->pwm->state.enabled in config
 * Replaced pm_runtime_resume_and_get with unconditional pm_runtime_get_sync()
   in config().
 * Restored duty_cycle > period check in rzg2l_gpt_get_state().
 * Added error check for clk_prepare_enable() in probe() and propagating error
   to the caller for pm_runtime_resume()
 * clk_get_rate() is called after enabling the clock and clk_rate_exclusive_get()
 * Simplified rzg2l_gpt_probe() by removing bitmap variables.
 * Added pm_runtime_idle() to suspend the device during probe.
 * Moved overflow condition check from config->probe().
 * Simplified rzg2l_gpt_reset_assert_pm_disable().
v12->v13:
 * Replaced Kconfig dependency from ARCH_RENESAS->ARCH_RZG2L
 * Sorted #include <linux/limits.h> alphabetically
 * Added a comment for mutex_lock to fix check patch warning
 * Replaced data type of duty_cycle from unsigned int->u32 as
   the maximum value stored is U32_MAX.
 * Improved rzg2l_gpt_config() by removing unwanted duty_cycle related code.
 * Improved rzg2l_gpt_get_state() by setting "val = rzg2l_gpt->duty_cycle[pwm->hwpwm];", 
   and factor "tmp = NSEC_PER_SEC * (u64)val;" out of the if-statement.
 * Started using DEFINE_RUNTIME_DEV_PM_OPS(), and dropped __maybe_unused
   from the callbacks.
v11->v12:
 * Added return code for get_state()
 * Cache duty cycle/prescale as the driver cannot read the current duty
   cycle/prescale from the hardware if the hardware is disabled. Cache the
   last programmed duty cycle/prescale value to return in that case.
 * Updated rzg2l_gpt_enable to enable the clocks.
 * Updated rzg2l_gpt_disable to disable the clocks.
 * Updated rzg2l_gpt_config() to cache duty cucle/prescale value
 * Updated rzg2l_gpt_get_state to use cached value of duty cycle/prescale,If the PWM
   is disabled.
 * Simplified rzg2l_gpt_apply()
 * Added comments in rzg2l_gpt_reset_assert_pm_disable()
v10->v11:
 * Used bitmap_zero for initializing bitmap varable.
 * Fixed clock imbalance during remove for the case bootloader turning
   on PWM and module unload is called just after the boot.
 * Fixed over flow condition in get_state() for a prescale value of 2 & more.
 * Improved rzg2l_gpt_cntr_need_stop() based on prescale as it is the
   only runtime variable.
 * Added array for Cache variables state_period and prescale
 * Probe caches the prescale value set by the bootloader.
 * Updated rzg2l_gpt_config() to make use of array variables.
v9->v10:
 * Updated the error handling in probe(), clk_disable_unprepare called
   on the error path.
 * Removed ch_en array and started using bitmask instead.
v8->v9:
 * deassert after devm_clk_get() to avoid reset stays deasserted,in case
   clk_get() fails.
 * Removed ch_offs from struct rzg2l_gpt_chip and use macro instead.
 * Updated error handling in probe()
v7->v8:
 * Modelled as single PWM device handling multiple channels
 * Replaced shared reset->devm_reset_control_get_exclusive()
 * Replaced iowrite32->writel and ioread32->readl
 * Updated prescale calculation
 * Added PM runtime callbacks
 * Updated PM handling and removed "pwm_enabled_by_bootloader" variable
 * Introduced rzg2l_gpt_is_ch_enabled for checking enable status on both
   IO's
 * Moved enable/disable output pins from config->enable/disable.
 * Added rzg2l_gpt_cntr_need_stop() for caching prescalar/mode values.
v6->v7:
 * Added the comment for cacheing rzg2l_gpt->state_period.
 * Fixed boundary values for pv and dc.
 * Added comment for modifying mode, prescaler, timer counter and buffer enable
   registers.
 * Fixed buffer overflow in get_state()
 * Removed unnecessary assignment of state->period value in get_state().
 * Fixed state->duty_cycle value in get_state().
 * Added a limitation for disabling the channels.
v5->v6:
 * Updated macros RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH and
   RZG2L_GTIOR_GTIOB_OUT_LO_END_TOGGLE_CMP_MATCH with computation
   involving FIELD_PREP macro.
 * Removed struct rzg2l_gpt_phase and started using RZG2L_GTCCR macro
   for duty_offset.
 * replaced misnomer real_period->state_period.
 * Added handling for values >= (1024 << 32) for both period
   and duty cycle.
 * Added comments for pwm {en,dis}abled by bootloader during probe.
v4->v5:
 * Added Hardware manual details
 * Replaced the comment GTCNT->Counter
 * Removed the macros RZG2L_GPT_IO_PER_CHANNEL and chip.npwm directly
   used in probe.
 * Removed the unsed macro RZG2L_GTPR_MAX_VALUE
 * Added driver prefix for the type name and the variable.
 * Initialization of per_channel data moved from request->probe.
 * Updated clr parameter for rzg2l_gpt_modify for Start count.
 * Started using mutex and usage_count for handling shared
   period and prescalar for the 2 channels.
 * Updated the comment cycle->period.
 * Removed clk_disable from rzg2l_gpt_reset_assert_pm_disable()
 * Replaced pc->rzg2l_gpt.
 * Updated prescale calculation.
 * Moved pm_runtime_{get_sync,put} from {request,free}->{enable,disable}
 * Removed platform_set_drvdata as it is unused
 * Removed the variable pwm_enabled_by_bootloader 
 * Added dev_err_probe in various error paths in probe.
 * Added an error message, if devm_pwmchip_add() fails.
v3->v4:
 * Changed the local variable type i from u16->u8 and prescaled_period_
   cycles from u64->u32 in calculate_prescale().
 * Replaced mul_u64_u64_div_u64()->mul_u64_u32_div()
 * Dropped the comma after the sentinel.
 * Add a variable to track pwm enabled by bootloader and added comments
   in probe().
 * Removed unnecessary rzg2l_gpt_reset_assert_pm_disable() from probe.
 * Replaced devm_clk_get()->devm_clk_get_prepared()
 * Removed devm_clk_get_optional_enabled()
v2->v3:
 * Updated limitation section
 * Added prefix "RZG2L_" for all macros
 * Modified prescale calculation
 * Removed pwm_set_chip_data
 * Updated comment related to modifying Mode and Prescaler
 * Updated setting of prescale value in rzg2l_gpt_config()
 * Removed else branch from rzg2l_gpt_get_state()
 * removed the err label from rzg2l_gpt_apply()
 * Added devm_clk_get_optional_enabled() to retain clk on status,
   in case bootloader turns on the clk of pwm.
 * Replaced devm_reset_control_get_exclusive->devm_reset_control_get_shared
   as single reset shared between 8 channels.
v1->v2:
 * Added Limitations section
 * dropped "_MASK" from the define names.
 * used named initializer for struct phase
 * Added gpt_pwm_device into a flexible array member in rzg2l_gpt_chip
 * Revised the logic for prescale
 * Added .get_state callback
 * Improved error handling in rzg2l_gpt_apply
 * Removed .remove callback
 * Tested driver with PWM_DEBUG enabled
RFC->V1:
 * Updated macros
 * replaced rzg2l_gpt_write_mask()->rzg2l_gpt_modify()
 * Added rzg2l_gpt_read()
---
 drivers/pwm/Kconfig         |  11 +
 drivers/pwm/Makefile        |   1 +
 drivers/pwm/pwm-rzg2l-gpt.c | 544 ++++++++++++++++++++++++++++++++++++
 3 files changed, 556 insertions(+)
 create mode 100644 drivers/pwm/pwm-rzg2l-gpt.c

On 04/10/2023 13:14, Biju Das wrote:

...
> +	ret = clk_rate_exclusive_get(rzg2l_gpt->clk);
> +	if (ret)
> +		goto err_clk_disable;
> +
> +	rzg2l_gpt->rate = clk_get_rate(rzg2l_gpt->clk);
> +	if (!rzg2l_gpt->rate) {
> +		dev_err_probe(&pdev->dev, -EINVAL, "gpt clk rate is 0");

ret = dev_err_probe

Otherwise you return success.

> +		goto err_clk_rate_put;
> +	}
> +
> +	/*
> +	 * Refuse clk rates > 1 GHz to prevent overflow later for computing
> +	 * period and duty cycle.
> +	 */
> +	if (rzg2l_gpt->rate > NSEC_PER_SEC) {
> +		ret = -EINVAL;
> +		goto err_clk_rate_put;
> +	}
> +
....

> +	rzg2l_gpt->chip.ops = &rzg2l_gpt_ops;
> +	rzg2l_gpt->chip.npwm = RZG2L_MAX_PWM_CHANNELS;
> +	ret = devm_pwmchip_add(&pdev->dev, &rzg2l_gpt->chip);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to add PWM chip\n");
> +
> +	pm_runtime_idle(&pdev->dev);
> +
> +	return 0;
> +
> +err_clk_rate_put:
> +	clk_rate_exclusive_put(rzg2l_gpt->clk);
> +err_clk_disable:
> +	clk_disable_unprepare(rzg2l_gpt->clk);
> +err_reset:
> +	reset_control_assert(rzg2l_gpt->rstc);
> +	return ret;
> +}
> +
> +static const struct of_device_id rzg2l_gpt_of_table[] = {
> +	{ .compatible = "renesas,rzg2l-gpt", },
> +	{ /* Sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, rzg2l_gpt_of_table);
> +
> +static struct platform_driver rzg2l_gpt_driver = {
> +	.driver = {
> +		.name = "pwm-rzg2l-gpt",
> +		.pm = pm_ptr(&rzg2l_gpt_pm_ops),
> +		.of_match_table = rzg2l_gpt_of_table,
> +	},
> +	.probe = rzg2l_gpt_probe,
> +};
> +module_platform_driver(rzg2l_gpt_driver);
> +
> +MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
> +MODULE_ALIAS("platform:pwm-rzg2l-gpt");

You should not need MODULE_ALIAS() in normal cases. If you need it,
usually it means your device ID table is wrong.


Best regards,
Krzysztof

Hi Krzysztof Kozlowski,

Thanks for the feedback.

> Subject: Re: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
> 
> On 04/10/2023 13:14, Biju Das wrote:
> 
> ...
> > +	ret = clk_rate_exclusive_get(rzg2l_gpt->clk);
> > +	if (ret)
> > +		goto err_clk_disable;
> > +
> > +	rzg2l_gpt->rate = clk_get_rate(rzg2l_gpt->clk);
> > +	if (!rzg2l_gpt->rate) {
> > +		dev_err_probe(&pdev->dev, -EINVAL, "gpt clk rate is 0");
> 
> ret = dev_err_probe
> 
> Otherwise you return success.

Agreed.

> 
> > +		goto err_clk_rate_put;
> > +	}
> > +
> > +	/*
> > +	 * Refuse clk rates > 1 GHz to prevent overflow later for computing
> > +	 * period and duty cycle.
> > +	 */
> > +	if (rzg2l_gpt->rate > NSEC_PER_SEC) {
> > +		ret = -EINVAL;
> > +		goto err_clk_rate_put;
> > +	}
> > +
> ....
> 
> > +	rzg2l_gpt->chip.ops = &rzg2l_gpt_ops;
> > +	rzg2l_gpt->chip.npwm = RZG2L_MAX_PWM_CHANNELS;
> > +	ret = devm_pwmchip_add(&pdev->dev, &rzg2l_gpt->chip);
> > +	if (ret)
> > +		return dev_err_probe(&pdev->dev, ret, "failed to add PWM
> chip\n");
> > +
> > +	pm_runtime_idle(&pdev->dev);
> > +
> > +	return 0;
> > +
> > +err_clk_rate_put:
> > +	clk_rate_exclusive_put(rzg2l_gpt->clk);
> > +err_clk_disable:
> > +	clk_disable_unprepare(rzg2l_gpt->clk);
> > +err_reset:
> > +	reset_control_assert(rzg2l_gpt->rstc);
> > +	return ret;
> > +}
> > +
> > +static const struct of_device_id rzg2l_gpt_of_table[] = {
> > +	{ .compatible = "renesas,rzg2l-gpt", },
> > +	{ /* Sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, rzg2l_gpt_of_table);
> > +
> > +static struct platform_driver rzg2l_gpt_driver = {
> > +	.driver = {
> > +		.name = "pwm-rzg2l-gpt",
> > +		.pm = pm_ptr(&rzg2l_gpt_pm_ops),
> > +		.of_match_table = rzg2l_gpt_of_table,
> > +	},
> > +	.probe = rzg2l_gpt_probe,
> > +};
> > +module_platform_driver(rzg2l_gpt_driver);
> > +
> > +MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
> > +MODULE_ALIAS("platform:pwm-rzg2l-gpt");
> 
> You should not need MODULE_ALIAS() in normal cases. If you need it, usually
> it means your device ID table is wrong.

OK, I will drop it.

I am waiting for review comments from others.

I will send V16 along with their comments if any.

Cheers,
Biju

Hi Biju,

kernel test robot noticed the following build errors:

[auto build test ERROR on 4aae44f65827f0213a7361cf9c32cfe06114473f]

url:    https://github.com/intel-lab-lkp/linux/commits/Biju-Das/dt-bindings-pwm-Add-RZ-G2L-GPT-binding/20231004-231907
base:   4aae44f65827f0213a7361cf9c32cfe06114473f
patch link:    https://lore.kernel.org/r/20231004111451.126195-4-biju.das.jz%40bp.renesas.com
patch subject: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
config: arm-allyesconfig (https://download.01.org/0day-ci/archive/20231005/202310052353.flpqN2Di-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231005/202310052353.flpqN2Di-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310052353.flpqN2Di-lkp@intel.com/

All errors (new ones prefixed by >>):

   arm-linux-gnueabi-ld: drivers/pwm/pwm-rzg2l-gpt.o: in function `rzg2l_gpt_config':
>> pwm-rzg2l-gpt.c:(.text+0xae8): undefined reference to `__aeabi_uldivmod'
>> arm-linux-gnueabi-ld: pwm-rzg2l-gpt.c:(.text+0xb50): undefined reference to `__aeabi_uldivmod'

Hi Biju,

kernel test robot noticed the following build errors:

[auto build test ERROR on 4aae44f65827f0213a7361cf9c32cfe06114473f]

url:    https://github.com/intel-lab-lkp/linux/commits/Biju-Das/dt-bindings-pwm-Add-RZ-G2L-GPT-binding/20231004-231907
base:   4aae44f65827f0213a7361cf9c32cfe06114473f
patch link:    https://lore.kernel.org/r/20231004111451.126195-4-biju.das.jz%40bp.renesas.com
patch subject: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20231006/202310060218.5lQtUezc-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231006/202310060218.5lQtUezc-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310060218.5lQtUezc-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/mips/kernel/head.o: in function `kernel_entry':
   (.ref.text+0xac): relocation truncated to fit: R_MIPS_26 against `start_kernel'
   init/main.o: in function `set_reset_devices':
   main.c:(.init.text+0x10): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x18): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `debug_kernel':
   main.c:(.init.text+0x50): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x58): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `quiet_kernel':
   main.c:(.init.text+0x90): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x98): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `warn_bootconfig':
   main.c:(.init.text+0xd0): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0xd8): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `init_setup':
   main.c:(.init.text+0x108): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x114): additional relocation overflows omitted from the output
   mips-linux-ld: drivers/pwm/pwm-rzg2l-gpt.o: in function `rzg2l_gpt_calculate_pv_or_dc':
>> pwm-rzg2l-gpt.c:(.text.rzg2l_gpt_calculate_pv_or_dc+0x138): undefined reference to `__udivdi3'

Hi Kernel test robot,

> Subject: Re: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
> 
> Hi Biju,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on 4aae44f65827f0213a7361cf9c32cfe06114473f]
> base:   4aae44f65827f0213a7361cf9c32cfe06114473f
> patch link:
> patch subject: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
> config: arm-allyesconfig
> compiler: arm-linux-gnueabi-gcc (GCC) 13.2.0 reproduce (this is a W=1
> build):
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new
> version of the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes:
> 
> All errors (new ones prefixed by >>):
> 
>    arm-linux-gnueabi-ld: drivers/pwm/pwm-rzg2l-gpt.o: in function
> `rzg2l_gpt_config':
> >> pwm-rzg2l-gpt.c:(.text+0xae8): undefined reference to `__aeabi_uldivmod'
> >> arm-linux-gnueabi-ld: pwm-rzg2l-gpt.c:(.text+0xb50): undefined reference
> to `__aeabi_uldivmod'

I can reproduce this with Ubutu-23.04 and the instructions mentioned above.

This issue is fixed by replacing
DIV_ROUND_UP()->DIV64_U64_ROUND_UP().

Cheers,
Biju

Hi kernel test robot,

> -----Original Message-----
> From: kernel test robot <lkp@intel.com>
> Sent: Thursday, October 5, 2023 7:29 PM
> Subject: Re: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
> 
> Hi Biju,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on 4aae44f65827f0213a7361cf9c32cfe06114473f]
> 
> All errors (new ones prefixed by >>):
> 
>    arch/mips/kernel/head.o: in function `kernel_entry':
>    (.ref.text+0xac): relocation truncated to fit: R_MIPS_26 against
> `start_kernel'
>    init/main.o: in function `set_reset_devices':
>    main.c:(.init.text+0x10): relocation truncated to fit: R_MIPS_26 against
> `_mcount'
>    main.c:(.init.text+0x18): relocation truncated to fit: R_MIPS_26 against
> `__sanitizer_cov_trace_pc'
>    init/main.o: in function `debug_kernel':
>    main.c:(.init.text+0x50): relocation truncated to fit: R_MIPS_26 against
> `_mcount'
>    main.c:(.init.text+0x58): relocation truncated to fit: R_MIPS_26 against
> `__sanitizer_cov_trace_pc'
>    init/main.o: in function `quiet_kernel':
>    main.c:(.init.text+0x90): relocation truncated to fit: R_MIPS_26 against
> `_mcount'
>    main.c:(.init.text+0x98): relocation truncated to fit: R_MIPS_26 against
> `__sanitizer_cov_trace_pc'
>    init/main.o: in function `warn_bootconfig':
>    main.c:(.init.text+0xd0): relocation truncated to fit: R_MIPS_26 against
> `_mcount'
>    main.c:(.init.text+0xd8): relocation truncated to fit: R_MIPS_26 against
> `__sanitizer_cov_trace_pc'
>    init/main.o: in function `init_setup':
>    main.c:(.init.text+0x108): relocation truncated to fit: R_MIPS_26
> against `_mcount'
>    main.c:(.init.text+0x114): additional relocation overflows omitted from
> the output
>    mips-linux-ld: drivers/pwm/pwm-rzg2l-gpt.o: in function
> `rzg2l_gpt_calculate_pv_or_dc':
> >> pwm-rzg2l-gpt.c:(.text.rzg2l_gpt_calculate_pv_or_dc+0x138): undefined
> reference to `__udivdi3'

I can reproduce this with Ubutu-23.04 and the instructions mentioned above.

Like arm32 compiler this issue also is fixed by replacing
DIV_ROUND_UP()->DIV64_U64_ROUND_UP().

Cheers,
Biju

Hello Uwe,

The clock rate for RZ/G2L family SoCs is 100 MHz.

With this, maximum possible period in nsec =  2^32 * 10 nsecs * 1024 (prescale) = 43,980,465,111,040 nsec which is well below than
2^64.

So I am planning to reject the PWM Period  > 43,980,465,111,040 nsecs in apply on next version.

Please correct me, if It is wrong.

Cheers,
Biju

> -----Original Message-----
> From: Biju Das <biju.das.jz@bp.renesas.com>
> Sent: Wednesday, October 4, 2023 12:15 PM
> Subject: [PATCH v16 3/4] pwm: Add support for RZ/G2L GPT
> 
> RZ/G2L General PWM Timer (GPT) composed of 8 channels with 32-bit timer
> (GPT32E). It supports the following functions
>  * 32 bits × 8 channels
>  * Up-counting or down-counting (saw waves) or up/down-counting
>    (triangle waves) for each counter.
>  * Clock sources independently selectable for each channel
>  * Two I/O pins per channel
>  * Two output compare/input capture registers per channel
>  * For the two output compare/input capture registers of each channel,
>    four registers are provided as buffer registers and are capable of
>    operating as comparison registers when buffering is not in use.
>  * In output compare operation, buffer switching can be at crests or
>    troughs, enabling the generation of laterally asymmetric PWM waveforms.
>  * Registers for setting up frame cycles in each channel (with capability
>    for generating interrupts at overflow or underflow)
>  * Generation of dead times in PWM operation
>  * Synchronous starting, stopping and clearing counters for arbitrary
>    channels
>  * Starting, stopping, clearing and up/down counters in response to input
>    level comparison
>  * Starting, clearing, stopping and up/down counters in response to a
>    maximum of four external triggers
>  * Output pin disable function by dead time error and detected
>    short-circuits between output pins
>  * A/D converter start triggers can be generated (GPT32E0 to GPT32E3)
>  * Enables the noise filter for input capture and external trigger
>    operation
> 
> Add basic pwm support for RZ/G2L GPT driver by creating separate logical
> channels for each IOs.
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v15->v16:
> * Replaced the macro DIV_ROUND_UP_ULL->DIV64_U64_ROUND_UP
> * Added DIV_ROUND_UP in rzg2l_gpt_calculate_pv_or_dc() to avoid loss of
>   precision.
> * Replaced min->min_t() in rzg2l_gpt_calculate_pv_or_dc().
> * Added a comment for rzg2l_gpt_config()
> * Replaced mul_u64_u32_div()->mul_u64_u64_div_u64() in rzg2l_gpt_config()
> * Fixed the logical condition related to counter stop in
>   rzg2l_gpt_config().
> * Dropped pm_runtime_resume_*() from rzg2l_gpt_config() as it is managed
>   by rzg2l_gpt_apply().
> * Moved pm_runtime_resume_*() from rzg2l_gpt_{en,dis}able() to
>   rzg2l_gpt_apply().
> v14->v15:
> * Added enable_count and ch_en_bits variables to struct rzg2l_gpt_chip
>   based on feedback for pwm_mtu3 driver.
> * Updated copyright header and commit description by replacing "This patch
>   adds"-> "Add"
> * Replaced macro RZG2L_GET_CH_INDEX->RZG2L_GET_CH and replaced ch_index-
> >ch
>   throughout
> * rzg2l_gpt_{enable,disable}() enables/disables PWM based on the
>   enable_count.
> * Replaced pm_runtime_get_sync->pm_runtime_resume_and_get and propogated
>   the error in rzg2l_gpt_get_state() and rzg2l_gpt_config()
> * Reduced variable scope in rzg2l_gpt_get_state() by moving most of
> variables
>   inside the if statement.
> * Updated rzg2l_gpt_get_state() by moving duty > period check
>   inside the top if block.
> * Added helper functions rzg2l_gpt_calculate_pv_or_dc()to simplify config.
>   Also Improved the logic in rzg2l_gpt_calculate_pv_or_dc() by using
>   min(period_or_duty_cycle >> (2 * prescale), (u64)U32_MAX);
> * Updated rzg2l_gpt_get_state() by moving duty > period check
>   inside the top if block.
> * Simplified rzg2l_gpt_config() for updating registers
> * Dropped pm_runtime_get_sync() and used bitmap variable "ch_en_bits"
>   to make balanced PM usage count in rzg2l_gpt_reset_assert_pm_disable()
>   For case were unbind is called before apply where pwm is enabled by
>   bootloader.
> * Added error check for clk_rate_exclusive_get() and clk_get_rate() in
>   probe().
> * Dropped prescale from struct rzg2l_gpt_chip.
> * Replaced of_match_ptr(rzg2l_gpt_of_table)->rzg2l_gpt_of_table in struct
>   rzg2l_gpt_driver
> v13->v14:
>  * Removed parenthesis for RZG2L_MAX_HW_CHANNELS and RZG2L_CHANNELS_PER_IO
>  * Removed duty_cycle variable from struct rzg2l_gpt_chip and added
> comment
>    for cache for prescale variable.
>  * Fixed a bug in rzg2l_gpt_cntr_need_stop().
>  * Reordered rzg2l_gpt_config() just above apply()
>  * Replaced pwm_is_enabled()->pwm->state.enabled in config
>  * Replaced pm_runtime_resume_and_get with unconditional
> pm_runtime_get_sync()
>    in config().
>  * Restored duty_cycle > period check in rzg2l_gpt_get_state().
>  * Added error check for clk_prepare_enable() in probe() and propagating
> error
>    to the caller for pm_runtime_resume()
>  * clk_get_rate() is called after enabling the clock and
> clk_rate_exclusive_get()
>  * Simplified rzg2l_gpt_probe() by removing bitmap variables.
>  * Added pm_runtime_idle() to suspend the device during probe.
>  * Moved overflow condition check from config->probe().
>  * Simplified rzg2l_gpt_reset_assert_pm_disable().
> v12->v13:
>  * Replaced Kconfig dependency from ARCH_RENESAS->ARCH_RZG2L
>  * Sorted #include <linux/limits.h> alphabetically
>  * Added a comment for mutex_lock to fix check patch warning
>  * Replaced data type of duty_cycle from unsigned int->u32 as
>    the maximum value stored is U32_MAX.
>  * Improved rzg2l_gpt_config() by removing unwanted duty_cycle related
> code.
>  * Improved rzg2l_gpt_get_state() by setting "val = rzg2l_gpt-
> >duty_cycle[pwm->hwpwm];",
>    and factor "tmp = NSEC_PER_SEC * (u64)val;" out of the if-statement.
>  * Started using DEFINE_RUNTIME_DEV_PM_OPS(), and dropped __maybe_unused
>    from the callbacks.
> v11->v12:
>  * Added return code for get_state()
>  * Cache duty cycle/prescale as the driver cannot read the current duty
>    cycle/prescale from the hardware if the hardware is disabled. Cache the
>    last programmed duty cycle/prescale value to return in that case.
>  * Updated rzg2l_gpt_enable to enable the clocks.
>  * Updated rzg2l_gpt_disable to disable the clocks.
>  * Updated rzg2l_gpt_config() to cache duty cucle/prescale value
>  * Updated rzg2l_gpt_get_state to use cached value of duty
> cycle/prescale,If the PWM
>    is disabled.
>  * Simplified rzg2l_gpt_apply()
>  * Added comments in rzg2l_gpt_reset_assert_pm_disable()
> v10->v11:
>  * Used bitmap_zero for initializing bitmap varable.
>  * Fixed clock imbalance during remove for the case bootloader turning
>    on PWM and module unload is called just after the boot.
>  * Fixed over flow condition in get_state() for a prescale value of 2 &
> more.
>  * Improved rzg2l_gpt_cntr_need_stop() based on prescale as it is the
>    only runtime variable.
>  * Added array for Cache variables state_period and prescale
>  * Probe caches the prescale value set by the bootloader.
>  * Updated rzg2l_gpt_config() to make use of array variables.
> v9->v10:
>  * Updated the error handling in probe(), clk_disable_unprepare called
>    on the error path.
>  * Removed ch_en array and started using bitmask instead.
> v8->v9:
>  * deassert after devm_clk_get() to avoid reset stays deasserted,in case
>    clk_get() fails.
>  * Removed ch_offs from struct rzg2l_gpt_chip and use macro instead.
>  * Updated error handling in probe()
> v7->v8:
>  * Modelled as single PWM device handling multiple channels
>  * Replaced shared reset->devm_reset_control_get_exclusive()
>  * Replaced iowrite32->writel and ioread32->readl
>  * Updated prescale calculation
>  * Added PM runtime callbacks
>  * Updated PM handling and removed "pwm_enabled_by_bootloader" variable
>  * Introduced rzg2l_gpt_is_ch_enabled for checking enable status on both
>    IO's
>  * Moved enable/disable output pins from config->enable/disable.
>  * Added rzg2l_gpt_cntr_need_stop() for caching prescalar/mode values.
> v6->v7:
>  * Added the comment for cacheing rzg2l_gpt->state_period.
>  * Fixed boundary values for pv and dc.
>  * Added comment for modifying mode, prescaler, timer counter and buffer
> enable
>    registers.
>  * Fixed buffer overflow in get_state()
>  * Removed unnecessary assignment of state->period value in get_state().
>  * Fixed state->duty_cycle value in get_state().
>  * Added a limitation for disabling the channels.
> v5->v6:
>  * Updated macros RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH and
>    RZG2L_GTIOR_GTIOB_OUT_LO_END_TOGGLE_CMP_MATCH with computation
>    involving FIELD_PREP macro.
>  * Removed struct rzg2l_gpt_phase and started using RZG2L_GTCCR macro
>    for duty_offset.
>  * replaced misnomer real_period->state_period.
>  * Added handling for values >= (1024 << 32) for both period
>    and duty cycle.
>  * Added comments for pwm {en,dis}abled by bootloader during probe.
> v4->v5:
>  * Added Hardware manual details
>  * Replaced the comment GTCNT->Counter
>  * Removed the macros RZG2L_GPT_IO_PER_CHANNEL and chip.npwm directly
>    used in probe.
>  * Removed the unsed macro RZG2L_GTPR_MAX_VALUE
>  * Added driver prefix for the type name and the variable.
>  * Initialization of per_channel data moved from request->probe.
>  * Updated clr parameter for rzg2l_gpt_modify for Start count.
>  * Started using mutex and usage_count for handling shared
>    period and prescalar for the 2 channels.
>  * Updated the comment cycle->period.
>  * Removed clk_disable from rzg2l_gpt_reset_assert_pm_disable()
>  * Replaced pc->rzg2l_gpt.
>  * Updated prescale calculation.
>  * Moved pm_runtime_{get_sync,put} from {request,free}->{enable,disable}
>  * Removed platform_set_drvdata as it is unused
>  * Removed the variable pwm_enabled_by_bootloader
>  * Added dev_err_probe in various error paths in probe.
>  * Added an error message, if devm_pwmchip_add() fails.
> v3->v4:
>  * Changed the local variable type i from u16->u8 and prescaled_period_
>    cycles from u64->u32 in calculate_prescale().
>  * Replaced mul_u64_u64_div_u64()->mul_u64_u32_div()
>  * Dropped the comma after the sentinel.
>  * Add a variable to track pwm enabled by bootloader and added comments
>    in probe().
>  * Removed unnecessary rzg2l_gpt_reset_assert_pm_disable() from probe.
>  * Replaced devm_clk_get()->devm_clk_get_prepared()
>  * Removed devm_clk_get_optional_enabled()
> v2->v3:
>  * Updated limitation section
>  * Added prefix "RZG2L_" for all macros
>  * Modified prescale calculation
>  * Removed pwm_set_chip_data
>  * Updated comment related to modifying Mode and Prescaler
>  * Updated setting of prescale value in rzg2l_gpt_config()
>  * Removed else branch from rzg2l_gpt_get_state()
>  * removed the err label from rzg2l_gpt_apply()
>  * Added devm_clk_get_optional_enabled() to retain clk on status,
>    in case bootloader turns on the clk of pwm.
>  * Replaced devm_reset_control_get_exclusive-
> >devm_reset_control_get_shared
>    as single reset shared between 8 channels.
> v1->v2:
>  * Added Limitations section
>  * dropped "_MASK" from the define names.
>  * used named initializer for struct phase
>  * Added gpt_pwm_device into a flexible array member in rzg2l_gpt_chip
>  * Revised the logic for prescale
>  * Added .get_state callback
>  * Improved error handling in rzg2l_gpt_apply
>  * Removed .remove callback
>  * Tested driver with PWM_DEBUG enabled
> RFC->V1:
>  * Updated macros
>  * replaced rzg2l_gpt_write_mask()->rzg2l_gpt_modify()
>  * Added rzg2l_gpt_read()
> ---
>  drivers/pwm/Kconfig         |  11 +
>  drivers/pwm/Makefile        |   1 +
>  drivers/pwm/pwm-rzg2l-gpt.c | 544 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 556 insertions(+)
>  create mode 100644 drivers/pwm/pwm-rzg2l-gpt.c
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index
> 6210babb0741..031ceaf09de7 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -503,6 +503,17 @@ config PWM_ROCKCHIP
>  	  Generic PWM framework driver for the PWM controller found on
>  	  Rockchip SoCs.
> 
> +config PWM_RZG2L_GPT
> +	tristate "Renesas RZ/G2L General PWM Timer support"
> +	depends on ARCH_RZG2L || COMPILE_TEST
> +	depends on HAS_IOMEM
> +	help
> +	  This driver exposes the General PWM Timer controller found in
> Renesas
> +	  RZ/G2L like chips through the PWM API.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called pwm-rzg2l-gpt.
> +
>  config PWM_RZ_MTU3
>  	tristate "Renesas RZ/G2L MTU3a PWM Timer support"
>  	depends on RZ_MTU3 || COMPILE_TEST
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index
> c822389c2a24..d579825f11bf 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_PWM_RASPBERRYPI_POE)	+= pwm-raspberrypi-
> poe.o
>  obj-$(CONFIG_PWM_RCAR)		+= pwm-rcar.o
>  obj-$(CONFIG_PWM_RENESAS_TPU)	+= pwm-renesas-tpu.o
>  obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
> +obj-$(CONFIG_PWM_RZG2L_GPT)	+= pwm-rzg2l-gpt.o
>  obj-$(CONFIG_PWM_RZ_MTU3)	+= pwm-rz-mtu3.o
>  obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
>  obj-$(CONFIG_PWM_SIFIVE)	+= pwm-sifive.o
> diff --git a/drivers/pwm/pwm-rzg2l-gpt.c b/drivers/pwm/pwm-rzg2l-gpt.c new
> file mode 100644 index 000000000000..1289b7f72e09
> --- /dev/null
> +++ b/drivers/pwm/pwm-rzg2l-gpt.c
> @@ -0,0 +1,544 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/G2L General PWM Timer (GPT) driver
> + *
> + * Copyright (C) 2023 Renesas Electronics Corporation
> + *
> + * Hardware manual for this IP can be found here
> + *
> +https://www.renesas.com/eu/en/document/mah/rzg2l-group-rzg2lc-group-use
> +rs-manual-hardware-0?language=en
> + *
> + * Limitations:
> + * - Counter must be stopped before modifying Mode and Prescaler.
> + * - When PWM is disabled, the output is driven to inactive.
> + * - While the hardware supports both polarities, the driver (for now)
> + *   only handles normal polarity.
> + * - When both channels are used, disabling the channel on one stops the
> + *   other.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/limits.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/pwm.h>
> +#include <linux/reset.h>
> +#include <linux/time.h>
> +
> +#define RZG2L_GTCR		0x2c
> +#define RZG2L_GTUDDTYC		0x30
> +#define RZG2L_GTIOR		0x34
> +#define RZG2L_GTBER		0x40
> +#define RZG2L_GTCNT		0x48
> +#define RZG2L_GTCCRA		0x4c
> +#define RZG2L_GTCCRB		0x50
> +#define RZG2L_GTPR		0x64
> +
> +#define RZG2L_GTCR_CST		BIT(0)
> +#define RZG2L_GTCR_MD		GENMASK(18, 16)
> +#define RZG2L_GTCR_TPCS		GENMASK(26, 24)
> +
> +#define RZG2L_GTCR_MD_SAW_WAVE_PWM_MODE	FIELD_PREP(RZG2L_GTCR_MD, 0)
> +
> +#define RZG2L_GTUDDTYC_UP	BIT(0)
> +#define RZG2L_GTUDDTYC_UDF	BIT(1)
> +#define RZG2L_UP_COUNTING	(RZG2L_GTUDDTYC_UP | RZG2L_GTUDDTYC_UDF)
> +
> +#define RZG2L_GTIOR_GTIOA	GENMASK(4, 0)
> +#define RZG2L_GTIOR_GTIOB	GENMASK(20, 16)
> +#define RZG2L_GTIOR_OAE		BIT(8)
> +#define RZG2L_GTIOR_OBE		BIT(24)
> +
> +#define RZG2L_INIT_OUT_LO_OUT_LO_END_TOGGLE	0x07
> +#define RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE	0x1b
> +
> +#define RZG2L_GTIOR_GTIOA_OUT_HI_END_TOGGLE_CMP_MATCH \
> +	(RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE | RZG2L_GTIOR_OAE) #define
> +RZG2L_GTIOR_GTIOA_OUT_LO_END_TOGGLE_CMP_MATCH \
> +	(RZG2L_INIT_OUT_LO_OUT_LO_END_TOGGLE | RZG2L_GTIOR_OAE) #define
> +RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH \
> +	(FIELD_PREP(RZG2L_GTIOR_GTIOB, RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE)
> |
> +RZG2L_GTIOR_OBE) #define RZG2L_GTIOR_GTIOB_OUT_LO_END_TOGGLE_CMP_MATCH \
> +	(FIELD_PREP(RZG2L_GTIOR_GTIOB, RZG2L_INIT_OUT_LO_OUT_LO_END_TOGGLE)
> |
> +RZG2L_GTIOR_OBE)
> +
> +#define RZG2L_GTCCR(i) (0x4c + 4 * (i))
> +
> +#define RZG2L_MAX_HW_CHANNELS	8
> +#define RZG2L_CHANNELS_PER_IO	2
> +#define RZG2L_MAX_PWM_CHANNELS	(RZG2L_MAX_HW_CHANNELS *
> RZG2L_CHANNELS_PER_IO)
> +
> +#define RZG2L_IS_IOB(a)	((a) & 0x1)
> +#define RZG2L_GET_CH(a)	((a) / 2)
> +
> +#define RZG2L_GET_CH_OFFS(i) (0x100 * (i))
> +
> +struct rzg2l_gpt_chip {
> +	struct pwm_chip chip;
> +	void __iomem *mmio;
> +	struct reset_control *rstc;
> +	struct clk *clk;
> +	struct mutex lock; /* lock to protect shared channel resources */
> +	unsigned long rate;
> +	u32 state_period[RZG2L_MAX_HW_CHANNELS];
> +	u32 user_count[RZG2L_MAX_HW_CHANNELS];
> +	u32 enable_count[RZG2L_MAX_HW_CHANNELS];
> +	DECLARE_BITMAP(ch_en_bits, RZG2L_MAX_PWM_CHANNELS); };
> +
> +static inline struct rzg2l_gpt_chip *to_rzg2l_gpt_chip(struct pwm_chip
> +*chip) {
> +	return container_of(chip, struct rzg2l_gpt_chip, chip); }
> +
> +static void rzg2l_gpt_write(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg,
> +u32 data) {
> +	writel(data, rzg2l_gpt->mmio + reg);
> +}
> +
> +static u32 rzg2l_gpt_read(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg) {
> +	return readl(rzg2l_gpt->mmio + reg);
> +}
> +
> +static void rzg2l_gpt_modify(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg,
> u32 clr,
> +			     u32 set)
> +{
> +	rzg2l_gpt_write(rzg2l_gpt, reg,
> +			(rzg2l_gpt_read(rzg2l_gpt, reg) & ~clr) | set); }
> +
> +static u8 rzg2l_gpt_calculate_prescale(struct rzg2l_gpt_chip *rzg2l_gpt,
> +				       u64 period_cycles)
> +{
> +	u32 prescaled_period_cycles;
> +	u8 prescale;
> +
> +	prescaled_period_cycles = period_cycles >> 32;
> +	if (prescaled_period_cycles >= 256)
> +		prescale = 5;
> +	else
> +		prescale = (fls(prescaled_period_cycles) + 1) / 2;
> +
> +	return prescale;
> +}
> +
> +static int rzg2l_gpt_request(struct pwm_chip *chip, struct pwm_device
> +*pwm) {
> +	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
> +	u32 ch = RZG2L_GET_CH(pwm->hwpwm);
> +
> +	mutex_lock(&rzg2l_gpt->lock);
> +	rzg2l_gpt->user_count[ch]++;
> +	mutex_unlock(&rzg2l_gpt->lock);
> +
> +	return 0;
> +}
> +
> +static void rzg2l_gpt_free(struct pwm_chip *chip, struct pwm_device
> +*pwm) {
> +	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
> +	u32 ch = RZG2L_GET_CH(pwm->hwpwm);
> +
> +	mutex_lock(&rzg2l_gpt->lock);
> +	rzg2l_gpt->user_count[ch]--;
> +	mutex_unlock(&rzg2l_gpt->lock);
> +}
> +
> +static bool rzg2l_gpt_is_ch_enabled(struct rzg2l_gpt_chip *rzg2l_gpt,
> +u8 hwpwm) {
> +	u8 ch = RZG2L_GET_CH(hwpwm);
> +	u32 offs = RZG2L_GET_CH_OFFS(ch);
> +	bool is_counter_running, is_output_en;
> +	u32 val;
> +
> +	val = rzg2l_gpt_read(rzg2l_gpt, offs + RZG2L_GTCR);
> +	is_counter_running = val & RZG2L_GTCR_CST;
> +
> +	val = rzg2l_gpt_read(rzg2l_gpt, offs + RZG2L_GTIOR);
> +	if (RZG2L_IS_IOB(hwpwm))
> +		is_output_en = val & RZG2L_GTIOR_OBE;
> +	else
> +		is_output_en = val & RZG2L_GTIOR_OAE;
> +
> +	return (is_counter_running && is_output_en); }
> +
> +static int rzg2l_gpt_enable(struct rzg2l_gpt_chip *rzg2l_gpt,
> +			    struct pwm_device *pwm)
> +{
> +	u8 ch = RZG2L_GET_CH(pwm->hwpwm);
> +	u32 offs = RZG2L_GET_CH_OFFS(ch);
> +
> +	/* Enable pin output */
> +	if (RZG2L_IS_IOB(pwm->hwpwm))
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTIOR,
> +				 RZG2L_GTIOR_GTIOB | RZG2L_GTIOR_OBE,
> +				 RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH);
> +	else
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTIOR,
> +				 RZG2L_GTIOR_GTIOA | RZG2L_GTIOR_OAE,
> +				 RZG2L_GTIOR_GTIOA_OUT_HI_END_TOGGLE_CMP_MATCH);
> +
> +	mutex_lock(&rzg2l_gpt->lock);
> +	if (!rzg2l_gpt->enable_count[ch])
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTCR, 0,
> RZG2L_GTCR_CST);
> +
> +	rzg2l_gpt->enable_count[ch]++;
> +	mutex_unlock(&rzg2l_gpt->lock);
> +
> +	return 0;
> +}
> +
> +static void rzg2l_gpt_disable(struct rzg2l_gpt_chip *rzg2l_gpt,
> +			      struct pwm_device *pwm)
> +{
> +	u8 ch = RZG2L_GET_CH(pwm->hwpwm);
> +	u32 offs = RZG2L_GET_CH_OFFS(ch);
> +
> +	/* Disable pin output */
> +	if (RZG2L_IS_IOB(pwm->hwpwm))
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTIOR,
> RZG2L_GTIOR_OBE, 0);
> +	else
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTIOR,
> RZG2L_GTIOR_OAE, 0);
> +
> +	/* Stop count, Output low on GTIOCx pin when counting stops */
> +	mutex_lock(&rzg2l_gpt->lock);
> +	rzg2l_gpt->enable_count[ch]--;
> +	if (!rzg2l_gpt->enable_count[ch])
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTCR, RZG2L_GTCR_CST,
> 0);
> +
> +	mutex_unlock(&rzg2l_gpt->lock);
> +
> +	/*
> +	 * Probe() set these bits, if pwm is enabled by bootloader. In such
> +	 * case, clearing the bits will avoid errors during unbind.
> +	 */
> +	if (test_bit(pwm->hwpwm, rzg2l_gpt->ch_en_bits))
> +		clear_bit(pwm->hwpwm, rzg2l_gpt->ch_en_bits); }
> +
> +static int rzg2l_gpt_get_state(struct pwm_chip *chip, struct pwm_device
> *pwm,
> +			       struct pwm_state *state)
> +{
> +	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
> +	int rc;
> +
> +	rc = pm_runtime_resume_and_get(chip->dev);
> +	if (rc)
> +		return rc;
> +
> +	state->enabled = rzg2l_gpt_is_ch_enabled(rzg2l_gpt, pwm->hwpwm);
> +	if (state->enabled) {
> +		u32 ch = RZG2L_GET_CH(pwm->hwpwm);
> +		u32 offs = RZG2L_GET_CH_OFFS(ch);
> +		u8 prescale;
> +		u64 tmp;
> +		u32 val;
> +
> +		val = rzg2l_gpt_read(rzg2l_gpt, offs + RZG2L_GTCR);
> +		prescale = FIELD_GET(RZG2L_GTCR_TPCS, val);
> +
> +		val = rzg2l_gpt_read(rzg2l_gpt, offs + RZG2L_GTPR);
> +		tmp = NSEC_PER_SEC * (u64)val;
> +		state->period = DIV64_U64_ROUND_UP(tmp, rzg2l_gpt->rate) << (2
> * prescale);
> +		val = rzg2l_gpt_read(rzg2l_gpt,
> +				     offs + RZG2L_GTCCR(RZG2L_IS_IOB(pwm-
> >hwpwm)));
> +
> +		tmp = NSEC_PER_SEC * (u64)val;
> +		state->duty_cycle = DIV64_U64_ROUND_UP(tmp, rzg2l_gpt->rate)
> << (2 *
> +prescale);
> +
> +		if (state->duty_cycle > state->period)
> +			state->duty_cycle = state->period;
> +	}
> +
> +	state->polarity = PWM_POLARITY_NORMAL;
> +	pm_runtime_put(chip->dev);
> +
> +	return 0;
> +}
> +
> +static u32 rzg2l_gpt_calculate_pv_or_dc(u64 period_or_duty_cycle, u8
> +prescale) {
> +	return min_t(u64, DIV_ROUND_UP(period_or_duty_cycle, 1 << (2 *
> prescale)),
> +		     (u64)U32_MAX);
> +}
> +
> +/* Caller holds the lock while calling rzg2l_gpt_config() */ static int
> +rzg2l_gpt_config(struct pwm_chip *chip, struct pwm_device *pwm,
> +			    const struct pwm_state *state)
> +{
> +	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
> +	u8 ch = RZG2L_GET_CH(pwm->hwpwm);
> +	u32 offs = RZG2L_GET_CH_OFFS(ch);
> +	unsigned long pv, dc;
> +	u64 period_cycles;
> +	u64 duty_cycles;
> +	u8 prescale;
> +
> +	/*
> +	 * GPT counter is shared by multiple channels, so prescale and
> period
> +	 * can NOT be modified when there are multiple channels in use with
> +	 * different settings.
> +	 */
> +	if (state->period != rzg2l_gpt->state_period[ch] && rzg2l_gpt-
> >user_count[ch] > 1)
> +		return -EBUSY;
> +
> +	period_cycles = mul_u64_u64_div_u64(state->period, rzg2l_gpt->rate,
> NSEC_PER_SEC);
> +	prescale = rzg2l_gpt_calculate_prescale(rzg2l_gpt, period_cycles);
> +
> +	pv = rzg2l_gpt_calculate_pv_or_dc(period_cycles, prescale);
> +
> +	duty_cycles = mul_u64_u64_div_u64(state->duty_cycle, rzg2l_gpt-
> >rate, NSEC_PER_SEC);
> +	dc = rzg2l_gpt_calculate_pv_or_dc(duty_cycles, prescale);
> +
> +	/*
> +	 * GPT counter is shared by multiple channels, we cache the period
> value
> +	 * from the first enabled channel and use the same value for both
> +	 * channels.
> +	 */
> +	rzg2l_gpt->state_period[ch] = state->period;
> +
> +	/*
> +	 * Counter must be stopped before modifying mode, prescaler, timer
> +	 * counter and buffer enable registers. These registers are shared
> +	 * between both channels. So allow updating these registers only for
> the
> +	 * first enabled channel.
> +	 */
> +	if (rzg2l_gpt->enable_count[ch] <= 1)
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTCR, RZG2L_GTCR_CST,
> 0);
> +
> +	/* GPT set operating mode (saw-wave up-counting) */
> +	rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTCR, RZG2L_GTCR_MD,
> +			 RZG2L_GTCR_MD_SAW_WAVE_PWM_MODE);
> +
> +	/* Set count direction */
> +	rzg2l_gpt_write(rzg2l_gpt, offs + RZG2L_GTUDDTYC,
> RZG2L_UP_COUNTING);
> +	/* Select count clock */
> +	rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTCR, RZG2L_GTCR_TPCS,
> +			 FIELD_PREP(RZG2L_GTCR_TPCS, prescale));
> +
> +	/* Set period */
> +	rzg2l_gpt_write(rzg2l_gpt, offs + RZG2L_GTPR, pv);
> +
> +	/* Set duty cycle */
> +	rzg2l_gpt_write(rzg2l_gpt, offs + RZG2L_GTCCR(RZG2L_IS_IOB(pwm-
> >hwpwm)),
> +			dc);
> +
> +	/* Set initial value for counter */
> +	rzg2l_gpt_write(rzg2l_gpt, offs + RZG2L_GTCNT, 0);
> +
> +	/* Set no buffer operation */
> +	rzg2l_gpt_write(rzg2l_gpt, offs + RZG2L_GTBER, 0);
> +
> +	/* Restart the counter after updating the registers */
> +	if (rzg2l_gpt->enable_count[ch] <= 1)
> +		rzg2l_gpt_modify(rzg2l_gpt, offs + RZG2L_GTCR,
> +				 RZG2L_GTCR_CST, RZG2L_GTCR_CST);
> +
> +	return 0;
> +}
> +
> +static int rzg2l_gpt_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> +			   const struct pwm_state *state)
> +{
> +	struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
> +	bool enabled = pwm->state.enabled;
> +	int ret;
> +
> +	if (state->polarity != PWM_POLARITY_NORMAL)
> +		return -EINVAL;
> +
> +	if (!state->enabled) {
> +		if (enabled) {
> +			rzg2l_gpt_disable(rzg2l_gpt, pwm);
> +			pm_runtime_put_sync(rzg2l_gpt->chip.dev);
> +		}
> +
> +		return 0;
> +	}
> +
> +	if (!enabled) {
> +		ret = pm_runtime_resume_and_get(rzg2l_gpt->chip.dev);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	mutex_lock(&rzg2l_gpt->lock);
> +	ret = rzg2l_gpt_config(chip, pwm, state);
> +	mutex_unlock(&rzg2l_gpt->lock);
> +	if (ret)
> +		return ret;
> +
> +	if (!enabled)
> +		ret = rzg2l_gpt_enable(rzg2l_gpt, pwm);
> +
> +	return ret;
> +}
> +
> +static const struct pwm_ops rzg2l_gpt_ops = {
> +	.request = rzg2l_gpt_request,
> +	.free = rzg2l_gpt_free,
> +	.get_state = rzg2l_gpt_get_state,
> +	.apply = rzg2l_gpt_apply,
> +	.owner = THIS_MODULE,
> +};
> +
> +static int rzg2l_gpt_pm_runtime_suspend(struct device *dev) {
> +	struct rzg2l_gpt_chip *rzg2l_gpt = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(rzg2l_gpt->clk);
> +
> +	return 0;
> +}
> +
> +static int rzg2l_gpt_pm_runtime_resume(struct device *dev) {
> +	struct rzg2l_gpt_chip *rzg2l_gpt = dev_get_drvdata(dev);
> +
> +	return clk_prepare_enable(rzg2l_gpt->clk);
> +}
> +
> +static DEFINE_RUNTIME_DEV_PM_OPS(rzg2l_gpt_pm_ops,
> +				 rzg2l_gpt_pm_runtime_suspend,
> +				 rzg2l_gpt_pm_runtime_resume, NULL);
> +
> +static void rzg2l_gpt_reset_assert_pm_disable(void *data) {
> +	struct rzg2l_gpt_chip *rzg2l_gpt = data;
> +	u32 i;
> +
> +	clk_rate_exclusive_put(rzg2l_gpt->clk);
> +	/*
> +	 * The below check is for making balanced PM usage count
> +	 * eg: boot loader is turning on PWM and probe increments the PM
> usage
> +	 * count. Before apply, if there is unbind/remove callback we need
> to
> +	 * decrement the PM usage count.
> +	 */
> +	for (i = 0; i < RZG2L_MAX_PWM_CHANNELS; i++) {
> +		if (test_bit(i, rzg2l_gpt->ch_en_bits))
> +			pm_runtime_put(rzg2l_gpt->chip.dev);
> +	}
> +
> +	pm_runtime_disable(rzg2l_gpt->chip.dev);
> +	pm_runtime_set_suspended(rzg2l_gpt->chip.dev);
> +	reset_control_assert(rzg2l_gpt->rstc);
> +}
> +
> +static int rzg2l_gpt_probe(struct platform_device *pdev) {
> +	struct rzg2l_gpt_chip *rzg2l_gpt;
> +	int ret;
> +	u32 i;
> +
> +	rzg2l_gpt = devm_kzalloc(&pdev->dev, sizeof(*rzg2l_gpt),
> GFP_KERNEL);
> +	if (!rzg2l_gpt)
> +		return -ENOMEM;
> +
> +	rzg2l_gpt->mmio = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(rzg2l_gpt->mmio))
> +		return PTR_ERR(rzg2l_gpt->mmio);
> +
> +	rzg2l_gpt->rstc = devm_reset_control_get_exclusive(&pdev->dev,
> NULL);
> +	if (IS_ERR(rzg2l_gpt->rstc))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(rzg2l_gpt->rstc),
> +				     "get reset failed\n");
> +
> +	rzg2l_gpt->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(rzg2l_gpt->clk))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(rzg2l_gpt->clk),
> +				     "cannot get clock\n");
> +
> +	ret = reset_control_deassert(rzg2l_gpt->rstc);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "cannot deassert reset control\n");
> +
> +	ret = clk_prepare_enable(rzg2l_gpt->clk);
> +	if (ret)
> +		goto err_reset;
> +
> +	ret = clk_rate_exclusive_get(rzg2l_gpt->clk);
> +	if (ret)
> +		goto err_clk_disable;
> +
> +	rzg2l_gpt->rate = clk_get_rate(rzg2l_gpt->clk);
> +	if (!rzg2l_gpt->rate) {
> +		dev_err_probe(&pdev->dev, -EINVAL, "gpt clk rate is 0");
> +		goto err_clk_rate_put;
> +	}
> +
> +	/*
> +	 * Refuse clk rates > 1 GHz to prevent overflow later for computing
> +	 * period and duty cycle.
> +	 */
> +	if (rzg2l_gpt->rate > NSEC_PER_SEC) {
> +		ret = -EINVAL;
> +		goto err_clk_rate_put;
> +	}
> +
> +	/*
> +	 *  We need to keep the clock on, in case the bootloader has enabled
> the
> +	 *  PWM and is running during probe().
> +	 */
> +	for (i = 0; i < RZG2L_MAX_PWM_CHANNELS; i++) {
> +		if (rzg2l_gpt_is_ch_enabled(rzg2l_gpt, i)) {
> +			set_bit(i, rzg2l_gpt->ch_en_bits);
> +			pm_runtime_get_sync(&pdev->dev);
> +		}
> +	}
> +
> +	mutex_init(&rzg2l_gpt->lock);
> +	platform_set_drvdata(pdev, rzg2l_gpt);
> +	rzg2l_gpt->chip.dev = &pdev->dev;
> +
> +	pm_runtime_set_active(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);
> +	ret = devm_add_action_or_reset(&pdev->dev,
> +				       rzg2l_gpt_reset_assert_pm_disable,
> +				       rzg2l_gpt);
> +	if (ret < 0)
> +		return ret;
> +
> +	rzg2l_gpt->chip.ops = &rzg2l_gpt_ops;
> +	rzg2l_gpt->chip.npwm = RZG2L_MAX_PWM_CHANNELS;
> +	ret = devm_pwmchip_add(&pdev->dev, &rzg2l_gpt->chip);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to add PWM
> chip\n");
> +
> +	pm_runtime_idle(&pdev->dev);
> +
> +	return 0;
> +
> +err_clk_rate_put:
> +	clk_rate_exclusive_put(rzg2l_gpt->clk);
> +err_clk_disable:
> +	clk_disable_unprepare(rzg2l_gpt->clk);
> +err_reset:
> +	reset_control_assert(rzg2l_gpt->rstc);
> +	return ret;
> +}
> +
> +static const struct of_device_id rzg2l_gpt_of_table[] = {
> +	{ .compatible = "renesas,rzg2l-gpt", },
> +	{ /* Sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, rzg2l_gpt_of_table);
> +
> +static struct platform_driver rzg2l_gpt_driver = {
> +	.driver = {
> +		.name = "pwm-rzg2l-gpt",
> +		.pm = pm_ptr(&rzg2l_gpt_pm_ops),
> +		.of_match_table = rzg2l_gpt_of_table,
> +	},
> +	.probe = rzg2l_gpt_probe,
> +};
> +module_platform_driver(rzg2l_gpt_driver);
> +
> +MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
> +MODULE_ALIAS("platform:pwm-rzg2l-gpt");
> +MODULE_DESCRIPTION("Renesas RZ/G2L General PWM Timer (GPT) Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1

On Thu, Nov 16, 2023 at 07:00:00PM +0000, Biju Das wrote:
> Hello Uwe,
> 
> The clock rate for RZ/G2L family SoCs is 100 MHz.
> 
> With this, maximum possible period in nsec =  2^32 * 10 nsecs * 1024 (prescale) = 43,980,465,111,040 nsec which is well below than
> 2^64.
> 
> So I am planning to reject the PWM Period  > 43,980,465,111,040 nsecs in apply on next version.
> 
> Please correct me, if It is wrong.

It's wrong. A request for a period > 43,980,465,111,040 ns should
configure 43,980,465,111,040 then.

(Rationale: If your HW could do 43,980,465,111,040 and 50,000,000,000,000
(and nothing in between) and you request 44,000,000,000,000 you get
43,980,465,111,040, right? That your hardware cannot do
50,000,000,000,000 is totally irrelevant for this request and the
resulting configuration. So go with 43,980,465,111,040 even if you
cannot do 50,000,000,000,000.)

Best regards
Uwe