[v3] clk/axs10x: Add I2S PLL clock driver

The ARC SDP I2S clock can be programmed using a
specific PLL.

This patch has the goal of adding a clock driver
that programs this PLL.

At this moment the rate values are hardcoded in
a table but in the future it would be ideal to
use a function which determines the PLL values
given the desired rate.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
---

Changes v2 -> v3:
* Implemented recalc_rate

Changes v1 -> v2:
* Renamed folder to axs10x (as suggested by Alexey Brodkin)
* Added more supported rates

 arch/arc/boot/dts/axs10x_mb.dtsi   |   5 ++
 drivers/clk/Makefile               |   1 +
 drivers/clk/axs10x/Makefile        |   1 +
 drivers/clk/axs10x/i2s_pll_clock.c | 163 +++++++++++++++++++++++++++++++++++++
 4 files changed, 170 insertions(+)
 create mode 100644 drivers/clk/axs10x/Makefile
 create mode 100644 drivers/clk/axs10x/i2s_pll_clock.c

On 03/31, Jose Abreu wrote:
>
>  arch/arc/boot/dts/axs10x_mb.dtsi   |   5 ++

Please remove this diff from this patch. dts changes go through
non-clk trees.

>  drivers/clk/Makefile               |   1 +
>  drivers/clk/axs10x/Makefile        |   1 +
>  drivers/clk/axs10x/i2s_pll_clock.c | 163 +++++++++++++++++++++++++++++++++++++

Where is the binding document?

> diff --git a/drivers/clk/axs10x/i2s_pll_clock.c b/drivers/clk/axs10x/i2s_pll_clock.c
> new file mode 100644
> index 0000000..f050e70
> --- /dev/null
> +++ b/drivers/clk/axs10x/i2s_pll_clock.c
> @@ -0,0 +1,163 @@
> +/* FPGA Version Info */
> +#define FPGA_VER_INFO	0xE0011230
> +#define FPGA_VER_27M	0x000FBED9
> +
> +/* PLL registers addresses */
> +#define PLL_IDIV_ADDR	0xE00100A0
> +#define PLL_FBDIV_ADDR	0xE00100A4
> +#define PLL_ODIV0_ADDR	0xE00100A8
> +#define PLL_ODIV1_ADDR	0xE00100AC
> +
> +struct i2s_pll_cfg {
> +	unsigned int rate;
> +	unsigned int idiv;
> +	unsigned int fbdiv;
> +	unsigned int odiv0;
> +	unsigned int odiv1;
> +};
> +
> +static struct i2s_pll_cfg i2s_pll_cfg_27m[] = {

const?

> +	/* 27 Mhz */
> +	{ 1024000, 0x104, 0x451, 0x10E38, 0x2000 },
> +	{ 1411200, 0x104, 0x596, 0x10D35, 0x2000 },
> +	{ 1536000, 0x208, 0xA28, 0x10B2C, 0x2000 },
> +	{ 2048000, 0x82, 0x451, 0x10E38, 0x2000 },
> +	{ 2822400, 0x82, 0x596, 0x10D35, 0x2000 },
> +	{ 3072000, 0x104, 0xA28, 0x10B2C, 0x2000 },
> +	{ 2116800, 0x82, 0x3CF, 0x10C30, 0x2000 },
> +	{ 2304000, 0x104, 0x79E, 0x10B2C, 0x2000 },
> +	{ 0, 0, 0, 0, 0 },
> +};
> +
> +static struct i2s_pll_cfg i2s_pll_cfg_28m[] = {

const?

> +	/* 28.224 Mhz */
> +	{ 1024000, 0x82, 0x105, 0x107DF, 0x2000 },
> +	{ 1411200, 0x28A, 0x1, 0x10001, 0x2000 },
> +	{ 1536000, 0xA28, 0x187, 0x10042, 0x2000 },
> +	{ 2048000, 0x41, 0x105, 0x107DF, 0x2000 },
> +	{ 2822400, 0x145, 0x1, 0x10001, 0x2000 },
> +	{ 3072000, 0x514, 0x187, 0x10042, 0x2000 },
> +	{ 2116800, 0x514, 0x42, 0x10001, 0x2000 },
> +	{ 2304000, 0x619, 0x82, 0x10001, 0x2000 },
> +	{ 0, 0, 0, 0, 0 },
> +};
> +
> +struct i2s_pll_clk {
> +	struct clk_hw hw;
> +	unsigned long ref_clk;
> +	struct i2s_pll_cfg *pll_cfg;
> +};
> +
> +static inline struct i2s_pll_clk *to_i2s_pll_clk(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct i2s_pll_clk, hw);
> +}
> +
> +static unsigned int i2s_pll_get_value(unsigned int val)
> +{
> +	return ((val & 0x3F) + ((val >> 6) & 0x3F));

Please drop extraneous parentheses.

> +}
> +
> +static unsigned long i2s_pll_recalc_rate(struct clk_hw *hw,
> +			unsigned long parent_rate)
> +{
> +	struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
> +	unsigned int idiv, fbdiv, odiv;
> +
> +	idiv = i2s_pll_get_value(readl((void *)PLL_IDIV_ADDR));

We need a real ioremap in this driver instead of casting physical
addresses to pointers and calling readl on them.

> +	fbdiv = i2s_pll_get_value(readl((void *)PLL_FBDIV_ADDR));
> +	odiv = i2s_pll_get_value(readl((void *)PLL_ODIV0_ADDR));
> +
> +	return (((clk->ref_clk / idiv ) * fbdiv) / odiv);

Again, too many parentheses. Also, any concerns of 32-bit
truncation here (i.e. is 64-bit math needed)?

> +}
> +
> +static long i2s_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> +			unsigned long *prate)
> +{
> +	/* TODO: Round rate to nearest valid rate */

At the least this should return the rate from the table if it's
there or failure if it isn't an exact match. Basically do exactly
what i2s_pll_set_rate() is doing without changing the rate.

> +	return rate;
> +}
> +
> +static int i2s_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> +			unsigned long parent_rate)
> +{
> +	struct i2s_pll_cfg *pll_cfg = to_i2s_pll_clk(hw)->pll_cfg;
> +	int i;
> +
> +	for (i = 0; pll_cfg[i].rate != 0; i++) {
> +		if (pll_cfg[i].rate == rate) {
> +			writel(pll_cfg[i].idiv, (void *)PLL_IDIV_ADDR);
> +			writel(pll_cfg[i].fbdiv, (void *)PLL_FBDIV_ADDR);
> +			writel(pll_cfg[i].odiv0, (void *)PLL_ODIV0_ADDR);
> +			writel(pll_cfg[i].odiv1, (void *)PLL_ODIV1_ADDR);
> +			return 0;
> +		}
> +	}
> +
> +	pr_err("%s: invalid rate=%ld, parent_rate=%ld\n", __func__,
> +			rate, parent_rate);
> +	return -EINVAL;
> +}
> +
> +static const struct clk_ops i2s_pll_ops = {
> +	.recalc_rate = i2s_pll_recalc_rate,
> +	.round_rate = i2s_pll_round_rate,
> +	.set_rate = i2s_pll_set_rate,
> +};
> +
> +static void __init i2s_pll_clk_setup(struct device_node *node)
> +{
> +	const char *clk_name = node->name;
> +	struct clk *clk;
> +	struct i2s_pll_clk *pll_clk;
> +	struct clk_init_data init;
> +
> +	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
> +	if (!pll_clk)
> +		return;
> +
> +	init.name = clk_name;
> +	init.ops = &i2s_pll_ops;
> +	init.flags = CLK_IS_BASIC;

Drop CLK_IS_BASIC unless you actually need it.

> +	init.num_parents = 0;
> +	pll_clk->hw.init = &init;
> +
> +	clk = clk_register(NULL, &pll_clk->hw);
> +	if (IS_ERR(clk)) {
> +		pr_err("%s: failed to register %s div clock (%ld)\n",
> +				__func__, clk_name, PTR_ERR(clk));
> +		goto free_clock;
> +	}
> +
> +	if (readl((void *)FPGA_VER_INFO) <= FPGA_VER_27M) {
> +		pll_clk->ref_clk = 27000000;

Refclk sounds like parent clk. Perhaps the DTS file should have a
fixes rate reference clk for this clk and then we could use
parent/child relationships in the clk framework to pass the
parent rate to the recalc/round_rate ops? I presume that the FPGA
info isn't in the same device/region as this clk is.

> +		pll_clk->pll_cfg = i2s_pll_cfg_27m;
> +	} else {
> +		pll_clk->ref_clk = 28224000;
> +		pll_clk->pll_cfg = i2s_pll_cfg_28m;
> +	}
> +
> +	of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +	return;
> +
> +free_clock:
> +	kfree(pll_clk);
> +}
> +
> +CLK_OF_DECLARE(i2s_pll_clk, "snps,i2s-pll-clock", i2s_pll_clk_setup);
> +

Can this be a platform driver instead of using CLK_OF_DECLARE?

On Thursday 31 March 2016 10:38 PM, Jose Abreu wrote:
> The ARC SDP I2S clock can be programmed using a
> specific PLL.
> 
> This patch has the goal of adding a clock driver
> that programs this PLL.
> 
> At this moment the rate values are hardcoded in
> a table but in the future it would be ideal to
> use a function which determines the PLL values
> given the desired rate.
> 
> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
> ---
> 
> Changes v2 -> v3:
> * Implemented recalc_rate
> 
> Changes v1 -> v2:
> * Renamed folder to axs10x (as suggested by Alexey Brodkin)
> * Added more supported rates
> 
>  arch/arc/boot/dts/axs10x_mb.dtsi   |   5 ++
>  drivers/clk/Makefile               |   1 +
>  drivers/clk/axs10x/Makefile        |   1 +
>  drivers/clk/axs10x/i2s_pll_clock.c | 163 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 170 insertions(+)
>  create mode 100644 drivers/clk/axs10x/Makefile
>  create mode 100644 drivers/clk/axs10x/i2s_pll_clock.c
> 
> diff --git a/arch/arc/boot/dts/axs10x_mb.dtsi b/arch/arc/boot/dts/axs10x_mb.dtsi
> index ab5d570..9c68226 100644
> --- a/arch/arc/boot/dts/axs10x_mb.dtsi
> +++ b/arch/arc/boot/dts/axs10x_mb.dtsi
> @@ -23,6 +23,11 @@
>  				#clock-cells = <0>;
>  			};
>  
> +			i2sclk: i2sclk {
> +				compatible = "snps,i2s-pll-clock";
> +				#clock-cells = <0>;
> +			};
> +
>  			apbclk: apbclk {
>  				compatible = "fixed-clock";
>  				clock-frequency = <50000000>;
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 46869d6..2ca62dc6 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -84,3 +84,4 @@ obj-$(CONFIG_X86)			+= x86/
>  obj-$(CONFIG_ARCH_ZX)			+= zte/
>  obj-$(CONFIG_ARCH_ZYNQ)			+= zynq/
>  obj-$(CONFIG_H8300)		+= h8300/
> +obj-$(CONFIG_ARC_PLAT_AXS10X)		+= axs10x/
> diff --git a/drivers/clk/axs10x/Makefile b/drivers/clk/axs10x/Makefile
> new file mode 100644
> index 0000000..01996b8
> --- /dev/null
> +++ b/drivers/clk/axs10x/Makefile
> @@ -0,0 +1 @@
> +obj-y += i2s_pll_clock.o
> diff --git a/drivers/clk/axs10x/i2s_pll_clock.c b/drivers/clk/axs10x/i2s_pll_clock.c
> new file mode 100644
> index 0000000..f050e70
> --- /dev/null
> +++ b/drivers/clk/axs10x/i2s_pll_clock.c
> @@ -0,0 +1,163 @@
> +/*
> + * Synopsys AXS10X SDP I2S PLL clock driver
> + *
> + * Copyright (C) 2016 Synopsys
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +#include <linux/clk-provider.h>
> +#include <linux/err.h>
> +#include <linux/device.h>
> +#include <linux/of_address.h>
> +#include <linux/slab.h>
> +
> +/* FPGA Version Info */
> +#define FPGA_VER_INFO	0xE0011230
> +#define FPGA_VER_27M	0x000FBED9
> +
> +/* PLL registers addresses */
> +#define PLL_IDIV_ADDR	0xE00100A0
> +#define PLL_FBDIV_ADDR	0xE00100A4
> +#define PLL_ODIV0_ADDR	0xE00100A8
> +#define PLL_ODIV1_ADDR	0xE00100AC
> +
> +struct i2s_pll_cfg {
> +	unsigned int rate;
> +	unsigned int idiv;
> +	unsigned int fbdiv;
> +	unsigned int odiv0;
> +	unsigned int odiv1;
> +};
> +
> +static struct i2s_pll_cfg i2s_pll_cfg_27m[] = {
> +	/* 27 Mhz */
> +	{ 1024000, 0x104, 0x451, 0x10E38, 0x2000 },
> +	{ 1411200, 0x104, 0x596, 0x10D35, 0x2000 },
> +	{ 1536000, 0x208, 0xA28, 0x10B2C, 0x2000 },
> +	{ 2048000, 0x82, 0x451, 0x10E38, 0x2000 },
> +	{ 2822400, 0x82, 0x596, 0x10D35, 0x2000 },
> +	{ 3072000, 0x104, 0xA28, 0x10B2C, 0x2000 },
> +	{ 2116800, 0x82, 0x3CF, 0x10C30, 0x2000 },
> +	{ 2304000, 0x104, 0x79E, 0x10B2C, 0x2000 },
> +	{ 0, 0, 0, 0, 0 },
> +};
> +
> +static struct i2s_pll_cfg i2s_pll_cfg_28m[] = {
> +	/* 28.224 Mhz */
> +	{ 1024000, 0x82, 0x105, 0x107DF, 0x2000 },
> +	{ 1411200, 0x28A, 0x1, 0x10001, 0x2000 },
> +	{ 1536000, 0xA28, 0x187, 0x10042, 0x2000 },
> +	{ 2048000, 0x41, 0x105, 0x107DF, 0x2000 },
> +	{ 2822400, 0x145, 0x1, 0x10001, 0x2000 },
> +	{ 3072000, 0x514, 0x187, 0x10042, 0x2000 },
> +	{ 2116800, 0x514, 0x42, 0x10001, 0x2000 },
> +	{ 2304000, 0x619, 0x82, 0x10001, 0x2000 },
> +	{ 0, 0, 0, 0, 0 },
> +};
> +
> +struct i2s_pll_clk {
> +	struct clk_hw hw;
> +	unsigned long ref_clk;
> +	struct i2s_pll_cfg *pll_cfg;
> +};
> +
> +static inline struct i2s_pll_clk *to_i2s_pll_clk(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct i2s_pll_clk, hw);
> +}

Abstraction is good, but do you really need this. I mean do you foresee future
changes where this implementation might change.

> +
> +static unsigned int i2s_pll_get_value(unsigned int val)
> +{
> +	return ((val & 0x3F) + ((val >> 6) & 0x3F));
> +}
> +
> +static unsigned long i2s_pll_recalc_rate(struct clk_hw *hw,
> +			unsigned long parent_rate)
> +{
> +	struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
> +	unsigned int idiv, fbdiv, odiv;
> +
> +	idiv = i2s_pll_get_value(readl((void *)PLL_IDIV_ADDR));
> +	fbdiv = i2s_pll_get_value(readl((void *)PLL_FBDIV_ADDR));
> +	odiv = i2s_pll_get_value(readl((void *)PLL_ODIV0_ADDR));

See comment below - you can probably use readl_relaxed()

> +
> +	return (((clk->ref_clk / idiv ) * fbdiv) / odiv);
> +}
> +
> +static long i2s_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> +			unsigned long *prate)
> +{
> +	/* TODO: Round rate to nearest valid rate */
> +	return rate;
> +}
> +
> +static int i2s_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> +			unsigned long parent_rate)
> +{
> +	struct i2s_pll_cfg *pll_cfg = to_i2s_pll_clk(hw)->pll_cfg;
> +	int i;
> +
> +	for (i = 0; pll_cfg[i].rate != 0; i++) {
> +		if (pll_cfg[i].rate == rate) {
> +			writel(pll_cfg[i].idiv, (void *)PLL_IDIV_ADDR);
> +			writel(pll_cfg[i].fbdiv, (void *)PLL_FBDIV_ADDR);
> +			writel(pll_cfg[i].odiv0, (void *)PLL_ODIV0_ADDR);
> +			writel(pll_cfg[i].odiv1, (void *)PLL_ODIV1_ADDR);

Note that there are writel_relaxed and readl_relaxed io accessors, which generate
better code, specially on ARC. If there is no strict ordering requirement for the
various PLL regs, you are safely use them.


> +			return 0;
> +		}
> +	}
> +
> +	pr_err("%s: invalid rate=%ld, parent_rate=%ld\n", __func__,
> +			rate, parent_rate);
> +	return -EINVAL;
> +}
> +
> +static const struct clk_ops i2s_pll_ops = {
> +	.recalc_rate = i2s_pll_recalc_rate,
> +	.round_rate = i2s_pll_round_rate,
> +	.set_rate = i2s_pll_set_rate,
> +};
> +
> +static void __init i2s_pll_clk_setup(struct device_node *node)
> +{
> +	const char *clk_name = node->name;
> +	struct clk *clk;
> +	struct i2s_pll_clk *pll_clk;
> +	struct clk_init_data init;
> +
> +	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
> +	if (!pll_clk)
> +		return;
> +
> +	init.name = clk_name;
> +	init.ops = &i2s_pll_ops;
> +	init.flags = CLK_IS_BASIC;
> +	init.num_parents = 0;
> +	pll_clk->hw.init = &init;
> +
> +	clk = clk_register(NULL, &pll_clk->hw);
> +	if (IS_ERR(clk)) {
> +		pr_err("%s: failed to register %s div clock (%ld)\n",
> +				__func__, clk_name, PTR_ERR(clk));
> +		goto free_clock;
> +	}
> +
> +	if (readl((void *)FPGA_VER_INFO) <= FPGA_VER_27M) {

readl_relaxed ?


> +		pll_clk->ref_clk = 27000000;
> +		pll_clk->pll_cfg = i2s_pll_cfg_27m;
> +	} else {
> +		pll_clk->ref_clk = 28224000;
> +		pll_clk->pll_cfg = i2s_pll_cfg_28m;
> +	}
> +
> +	of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +	return;
> +
> +free_clock:
> +	kfree(pll_clk);
> +}
> +
> +CLK_OF_DECLARE(i2s_pll_clk, "snps,i2s-pll-clock", i2s_pll_clk_setup);
> +
>

Hi Stephen,


On 02-04-2016 02:02, Stephen Boyd wrote:
> On 03/31, Jose Abreu wrote:
>>  arch/arc/boot/dts/axs10x_mb.dtsi   |   5 ++
> Please remove this diff from this patch. dts changes go through
> non-clk trees.

Ok.

>
>>  drivers/clk/Makefile               |   1 +
>>  drivers/clk/axs10x/Makefile        |   1 +
>>  drivers/clk/axs10x/i2s_pll_clock.c | 163 +++++++++++++++++++++++++++++++++++++
> Where is the binding document?

Will send in next version.

>> diff --git a/drivers/clk/axs10x/i2s_pll_clock.c b/drivers/clk/axs10x/i2s_pll_clock.c
>> new file mode 100644
>> index 0000000..f050e70
>> --- /dev/null
>> +++ b/drivers/clk/axs10x/i2s_pll_clock.c
>> @@ -0,0 +1,163 @@
>> +/* FPGA Version Info */
>> +#define FPGA_VER_INFO	0xE0011230
>> +#define FPGA_VER_27M	0x000FBED9
>> +
>> +/* PLL registers addresses */
>> +#define PLL_IDIV_ADDR	0xE00100A0
>> +#define PLL_FBDIV_ADDR	0xE00100A4
>> +#define PLL_ODIV0_ADDR	0xE00100A8
>> +#define PLL_ODIV1_ADDR	0xE00100AC
>> +
>> +struct i2s_pll_cfg {
>> +	unsigned int rate;
>> +	unsigned int idiv;
>> +	unsigned int fbdiv;
>> +	unsigned int odiv0;
>> +	unsigned int odiv1;
>> +};
>> +
>> +static struct i2s_pll_cfg i2s_pll_cfg_27m[] = {
> const?

Will change.

>
>> +	/* 27 Mhz */
>> +	{ 1024000, 0x104, 0x451, 0x10E38, 0x2000 },
>> +	{ 1411200, 0x104, 0x596, 0x10D35, 0x2000 },
>> +	{ 1536000, 0x208, 0xA28, 0x10B2C, 0x2000 },
>> +	{ 2048000, 0x82, 0x451, 0x10E38, 0x2000 },
>> +	{ 2822400, 0x82, 0x596, 0x10D35, 0x2000 },
>> +	{ 3072000, 0x104, 0xA28, 0x10B2C, 0x2000 },
>> +	{ 2116800, 0x82, 0x3CF, 0x10C30, 0x2000 },
>> +	{ 2304000, 0x104, 0x79E, 0x10B2C, 0x2000 },
>> +	{ 0, 0, 0, 0, 0 },
>> +};
>> +
>> +static struct i2s_pll_cfg i2s_pll_cfg_28m[] = {
> const?

Will change.

>
>> +	/* 28.224 Mhz */
>> +	{ 1024000, 0x82, 0x105, 0x107DF, 0x2000 },
>> +	{ 1411200, 0x28A, 0x1, 0x10001, 0x2000 },
>> +	{ 1536000, 0xA28, 0x187, 0x10042, 0x2000 },
>> +	{ 2048000, 0x41, 0x105, 0x107DF, 0x2000 },
>> +	{ 2822400, 0x145, 0x1, 0x10001, 0x2000 },
>> +	{ 3072000, 0x514, 0x187, 0x10042, 0x2000 },
>> +	{ 2116800, 0x514, 0x42, 0x10001, 0x2000 },
>> +	{ 2304000, 0x619, 0x82, 0x10001, 0x2000 },
>> +	{ 0, 0, 0, 0, 0 },
>> +};
>> +
>> +struct i2s_pll_clk {
>> +	struct clk_hw hw;
>> +	unsigned long ref_clk;
>> +	struct i2s_pll_cfg *pll_cfg;
>> +};
>> +
>> +static inline struct i2s_pll_clk *to_i2s_pll_clk(struct clk_hw *hw)
>> +{
>> +	return container_of(hw, struct i2s_pll_clk, hw);
>> +}
>> +
>> +static unsigned int i2s_pll_get_value(unsigned int val)
>> +{
>> +	return ((val & 0x3F) + ((val >> 6) & 0x3F));
> Please drop extraneous parentheses.

Ok.

>> +}
>> +
>> +static unsigned long i2s_pll_recalc_rate(struct clk_hw *hw,
>> +			unsigned long parent_rate)
>> +{
>> +	struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
>> +	unsigned int idiv, fbdiv, odiv;
>> +
>> +	idiv = i2s_pll_get_value(readl((void *)PLL_IDIV_ADDR));
> We need a real ioremap in this driver instead of casting physical
> addresses to pointers and calling readl on them.

Will implement in next version.

>
>> +	fbdiv = i2s_pll_get_value(readl((void *)PLL_FBDIV_ADDR));
>> +	odiv = i2s_pll_get_value(readl((void *)PLL_ODIV0_ADDR));
>> +
>> +	return (((clk->ref_clk / idiv ) * fbdiv) / odiv);
> Again, too many parentheses. Also, any concerns of 32-bit
> truncation here (i.e. is 64-bit math needed)?

You are right there is no need to use 64-bit math, will change in next version.
>
>> +}
>> +
>> +static long i2s_pll_round_rate(struct clk_hw *hw, unsigned long rate,
>> +			unsigned long *prate)
>> +{
>> +	/* TODO: Round rate to nearest valid rate */
> At the least this should return the rate from the table if it's
> there or failure if it isn't an exact match. Basically do exactly
> what i2s_pll_set_rate() is doing without changing the rate.

Ok, will implement.

>
>> +	return rate;
>> +}
>> +
>> +static int i2s_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>> +			unsigned long parent_rate)
>> +{
>> +	struct i2s_pll_cfg *pll_cfg = to_i2s_pll_clk(hw)->pll_cfg;
>> +	int i;
>> +
>> +	for (i = 0; pll_cfg[i].rate != 0; i++) {
>> +		if (pll_cfg[i].rate == rate) {
>> +			writel(pll_cfg[i].idiv, (void *)PLL_IDIV_ADDR);
>> +			writel(pll_cfg[i].fbdiv, (void *)PLL_FBDIV_ADDR);
>> +			writel(pll_cfg[i].odiv0, (void *)PLL_ODIV0_ADDR);
>> +			writel(pll_cfg[i].odiv1, (void *)PLL_ODIV1_ADDR);
>> +			return 0;
>> +		}
>> +	}
>> +
>> +	pr_err("%s: invalid rate=%ld, parent_rate=%ld\n", __func__,
>> +			rate, parent_rate);
>> +	return -EINVAL;
>> +}
>> +
>> +static const struct clk_ops i2s_pll_ops = {
>> +	.recalc_rate = i2s_pll_recalc_rate,
>> +	.round_rate = i2s_pll_round_rate,
>> +	.set_rate = i2s_pll_set_rate,
>> +};
>> +
>> +static void __init i2s_pll_clk_setup(struct device_node *node)
>> +{
>> +	const char *clk_name = node->name;
>> +	struct clk *clk;
>> +	struct i2s_pll_clk *pll_clk;
>> +	struct clk_init_data init;
>> +
>> +	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
>> +	if (!pll_clk)
>> +		return;
>> +
>> +	init.name = clk_name;
>> +	init.ops = &i2s_pll_ops;
>> +	init.flags = CLK_IS_BASIC;
> Drop CLK_IS_BASIC unless you actually need it.

Ok.

>
>> +	init.num_parents = 0;
>> +	pll_clk->hw.init = &init;
>> +
>> +	clk = clk_register(NULL, &pll_clk->hw);
>> +	if (IS_ERR(clk)) {
>> +		pr_err("%s: failed to register %s div clock (%ld)\n",
>> +				__func__, clk_name, PTR_ERR(clk));
>> +		goto free_clock;
>> +	}
>> +
>> +	if (readl((void *)FPGA_VER_INFO) <= FPGA_VER_27M) {
>> +		pll_clk->ref_clk = 27000000;
> Refclk sounds like parent clk. Perhaps the DTS file should have a
> fixes rate reference clk for this clk and then we could use
> parent/child relationships in the clk framework to pass the
> parent rate to the recalc/round_rate ops? I presume that the FPGA
> info isn't in the same device/region as this clk is.

The FPGA info is in a separate version. But if I implemented this in DTS file we
would need two files, one for older version of FPGA and another one for the new
version, right? The differences between the versions are only the reference
clock value, I think it is not really worth to have a new file to change only
one clock value, is there any other solution?

>
>> +		pll_clk->pll_cfg = i2s_pll_cfg_27m;
>> +	} else {
>> +		pll_clk->ref_clk = 28224000;
>> +		pll_clk->pll_cfg = i2s_pll_cfg_28m;
>> +	}
>> +
>> +	of_clk_add_provider(node, of_clk_src_simple_get, clk);
>> +	return;
>> +
>> +free_clock:
>> +	kfree(pll_clk);
>> +}
>> +
>> +CLK_OF_DECLARE(i2s_pll_clk, "snps,i2s-pll-clock", i2s_pll_clk_setup);
>> +
> Can this be a platform driver instead of using CLK_OF_DECLARE?

Something like this [1] ?

[1] http://lxr.free-electrons.com/source/drivers/clk/clk-scpi.c

Best regards,
Jose Miguel Abreu

On 04/04, Jose Abreu wrote:
> >> +	fbdiv = i2s_pll_get_value(readl((void *)PLL_FBDIV_ADDR));
> >> +	odiv = i2s_pll_get_value(readl((void *)PLL_ODIV0_ADDR));
> >> +
> >> +	return (((clk->ref_clk / idiv ) * fbdiv) / odiv);
> > Again, too many parentheses. Also, any concerns of 32-bit
> > truncation here (i.e. is 64-bit math needed)?
> 
> You are right there is no need to use 64-bit math, will change in next version.

Well it wasn't 64-bit math in the first place, so the question
was more if you wanted to use 64-bit math.