mmc: atmel: convert to gpio descriptos

From: Arnd Bergmann <arnd@arndb.de>

All Atmel (now Microchip) machines boot using DT, so the
old platform_data for this driver is no longer used by any
boards.

Removing the pdata probe lets us simplify the GPIO handling
with the use of the descriptor API.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/mmc/host/atmel-mci.c | 179 +++++++++++++++--------------------
 include/linux/atmel-mci.h    |  46 ---------
 2 files changed, 77 insertions(+), 148 deletions(-)
 delete mode 100644 include/linux/atmel-mci.h

On Thu, 26 Jan 2023 14:50:04 +0100 Arnd Bergmann wrote:
> Subject: [PATCH] mmc: atmel: convert to gpio descriptos

nit: descriptoRs

Hi Arnd,

On 26/01/2023 at 14:50, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> All Atmel (now Microchip) machines boot using DT, so the
> old platform_data for this driver is no longer used by any
> boards.
> 
> Removing the pdata probe lets us simplify the GPIO handling
> with the use of the descriptor API.

Thanks for your patch. I would like to know if it's related to the 
initiative started by Bala in this series:

https://lore.kernel.org/all/20221226073908.17317-1-balamanikandan.gunasundar@microchip.com/

It's true that it didn't come to a conclusion yet...

Regards,
   Nicolas

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   drivers/mmc/host/atmel-mci.c | 179 +++++++++++++++--------------------
>   include/linux/atmel-mci.h    |  46 ---------
>   2 files changed, 77 insertions(+), 148 deletions(-)
>   delete mode 100644 include/linux/atmel-mci.h
> 
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index bb9bbf1c927b..40006a960277 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -30,7 +30,6 @@
>   #include <linux/mmc/host.h>
>   #include <linux/mmc/sdio.h>
> 
> -#include <linux/atmel-mci.h>
>   #include <linux/atmel_pdc.h>
>   #include <linux/pm.h>
>   #include <linux/pm_runtime.h>
> @@ -40,6 +39,30 @@
>   #include <asm/io.h>
>   #include <asm/unaligned.h>
> 
> +#define ATMCI_MAX_NR_SLOTS     2
> +
> +/**
> + * struct mci_slot_pdata - board-specific per-slot configuration
> + * @bus_width: Number of data lines wired up the slot
> + * @wp_pin: GPIO pin wired to the write protect sensor
> + * @detect_is_active_high: The state of the detect pin when it is active
> + * @non_removable: The slot is not removable, only detect once
> + *
> + * If a given slot is not present on the board, @bus_width should be
> + * set to 0. The other fields are ignored in this case.
> + *
> + * Any pins that aren't available should be set to a negative value.
> + *
> + * Note that support for multiple slots is experimental -- some cards
> + * might get upset if we don't get the clock management exactly right.
> + * But in most cases, it should work just fine.
> + */
> +struct mci_slot_pdata {
> +       unsigned int            bus_width;
> +       bool                    detect_is_active_high;
> +       bool                    non_removable;
> +};
> +
>   /*
>    * Superset of MCI IP registers integrated in Atmel AT91 Processor
>    * Registers and bitfields marked with [2] are only available in MCI2
> @@ -388,8 +411,8 @@ struct atmel_mci_slot {
>   #define ATMCI_CARD_NEED_INIT   1
>   #define ATMCI_SHUTDOWN         2
> 
> -       int                     detect_pin;
> -       int                     wp_pin;
> +       struct gpio_desc        *detect_pin;
> +       struct gpio_desc        *wp_pin;
>          bool                    detect_is_active_high;
> 
>          struct timer_list       detect_timer;
> @@ -593,7 +616,6 @@ static void atmci_init_debugfs(struct atmel_mci_slot *slot)
>                             &host->completed_events);
>   }
> 
> -#if defined(CONFIG_OF)
>   static const struct of_device_id atmci_dt_ids[] = {
>          { .compatible = "atmel,hsmci" },
>          { /* sentinel */ }
> @@ -601,23 +623,13 @@ static const struct of_device_id atmci_dt_ids[] = {
> 
>   MODULE_DEVICE_TABLE(of, atmci_dt_ids);
> 
> -static struct mci_platform_data*
> -atmci_of_init(struct platform_device *pdev)
> +static int
> +atmci_of_init(struct platform_device *pdev, struct mci_slot_pdata *pdata)
>   {
>          struct device_node *np = pdev->dev.of_node;
>          struct device_node *cnp;
> -       struct mci_platform_data *pdata;
>          u32 slot_id;
> 
> -       if (!np) {
> -               dev_err(&pdev->dev, "device node not found\n");
> -               return ERR_PTR(-EINVAL);
> -       }
> -
> -       pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> -       if (!pdata)
> -               return ERR_PTR(-ENOMEM);
> -
>          for_each_child_of_node(np, cnp) {
>                  if (of_property_read_u32(cnp, "reg", &slot_id)) {
>                          dev_warn(&pdev->dev, "reg property is missing for %pOF\n",
> @@ -633,31 +645,18 @@ atmci_of_init(struct platform_device *pdev)
>                  }
> 
>                  if (of_property_read_u32(cnp, "bus-width",
> -                                        &pdata->slot[slot_id].bus_width))
> -                       pdata->slot[slot_id].bus_width = 1;
> -
> -               pdata->slot[slot_id].detect_pin =
> -                       of_get_named_gpio(cnp, "cd-gpios", 0);
> +                                        &pdata[slot_id].bus_width))
> +                       pdata[slot_id].bus_width = 1;
> 
> -               pdata->slot[slot_id].detect_is_active_high =
> +               pdata[slot_id].detect_is_active_high =
>                          of_property_read_bool(cnp, "cd-inverted");
> 
> -               pdata->slot[slot_id].non_removable =
> +               pdata[slot_id].non_removable =
>                          of_property_read_bool(cnp, "non-removable");
> -
> -               pdata->slot[slot_id].wp_pin =
> -                       of_get_named_gpio(cnp, "wp-gpios", 0);
>          }
> 
> -       return pdata;
> -}
> -#else /* CONFIG_OF */
> -static inline struct mci_platform_data*
> -atmci_of_init(struct platform_device *dev)
> -{
> -       return ERR_PTR(-EINVAL);
> +       return 0;
>   }
> -#endif
> 
>   static inline unsigned int atmci_get_version(struct atmel_mci *host)
>   {
> @@ -1509,8 +1508,8 @@ static int atmci_get_ro(struct mmc_host *mmc)
>          int                     read_only = -ENOSYS;
>          struct atmel_mci_slot   *slot = mmc_priv(mmc);
> 
> -       if (gpio_is_valid(slot->wp_pin)) {
> -               read_only = gpio_get_value(slot->wp_pin);
> +       if (slot->wp_pin) {
> +               read_only = gpiod_get_value(slot->wp_pin);
>                  dev_dbg(&mmc->class_dev, "card is %s\n",
>                                  read_only ? "read-only" : "read-write");
>          }
> @@ -1523,8 +1522,8 @@ static int atmci_get_cd(struct mmc_host *mmc)
>          int                     present = -ENOSYS;
>          struct atmel_mci_slot   *slot = mmc_priv(mmc);
> 
> -       if (gpio_is_valid(slot->detect_pin)) {
> -               present = !(gpio_get_value(slot->detect_pin) ^
> +       if (slot->detect_pin) {
> +               present = !(gpiod_get_value(slot->detect_pin) ^
>                              slot->detect_is_active_high);
>                  dev_dbg(&mmc->class_dev, "card is %spresent\n",
>                                  present ? "" : "not ");
> @@ -1637,8 +1636,8 @@ static void atmci_detect_change(struct timer_list *t)
>          if (test_bit(ATMCI_SHUTDOWN, &slot->flags))
>                  return;
> 
> -       enable_irq(gpio_to_irq(slot->detect_pin));
> -       present = !(gpio_get_value(slot->detect_pin) ^
> +       enable_irq(gpiod_to_irq(slot->detect_pin));
> +       present = !(gpiod_get_value(slot->detect_pin) ^
>                      slot->detect_is_active_high);
>          present_old = test_bit(ATMCI_CARD_PRESENT, &slot->flags);
> 
> @@ -2231,18 +2230,15 @@ static int atmci_init_slot(struct atmel_mci *host,
>          slot = mmc_priv(mmc);
>          slot->mmc = mmc;
>          slot->host = host;
> -       slot->detect_pin = slot_data->detect_pin;
> -       slot->wp_pin = slot_data->wp_pin;
>          slot->detect_is_active_high = slot_data->detect_is_active_high;
>          slot->sdc_reg = sdc_reg;
>          slot->sdio_irq = sdio_irq;
> 
>          dev_dbg(&mmc->class_dev,
> -               "slot[%u]: bus_width=%u, detect_pin=%d, "
> -               "detect_is_active_high=%s, wp_pin=%d\n",
> -               id, slot_data->bus_width, slot_data->detect_pin,
> -               slot_data->detect_is_active_high ? "true" : "false",
> -               slot_data->wp_pin);
> +               "slot[%u]: bus_width=%u, "
> +               "detect_is_active_high=%s\n",
> +               id, slot_data->bus_width,
> +               slot_data->detect_is_active_high ? "true" : "false");
> 
>          mmc->ops = &atmci_ops;
>          mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
> @@ -2278,30 +2274,29 @@ static int atmci_init_slot(struct atmel_mci *host,
> 
>          /* Assume card is present initially */
>          set_bit(ATMCI_CARD_PRESENT, &slot->flags);
> -       if (gpio_is_valid(slot->detect_pin)) {
> -               if (devm_gpio_request(&host->pdev->dev, slot->detect_pin,
> -                                     "mmc_detect")) {
> -                       dev_dbg(&mmc->class_dev, "no detect pin available\n");
> -                       slot->detect_pin = -EBUSY;
> -               } else if (gpio_get_value(slot->detect_pin) ^
> -                               slot->detect_is_active_high) {
> +
> +       slot->detect_pin = devm_gpiod_get_optional(&host->pdev->dev, "cd", GPIOD_IN);
> +       if (!IS_ERR(slot->detect_pin)) {
> +               dev_dbg(&mmc->class_dev, "no detect pin available\n");
> +               slot->detect_pin = NULL;
> +       } else if (slot->detect_pin) {
> +               if (gpiod_get_value(slot->detect_pin) ^
> +                   slot->detect_is_active_high) {
>                          clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
>                  }
>          }
> 
> -       if (!gpio_is_valid(slot->detect_pin)) {
> +       if (!slot->detect_pin) {
>                  if (slot_data->non_removable)
>                          mmc->caps |= MMC_CAP_NONREMOVABLE;
>                  else
>                          mmc->caps |= MMC_CAP_NEEDS_POLL;
>          }
> 
> -       if (gpio_is_valid(slot->wp_pin)) {
> -               if (devm_gpio_request(&host->pdev->dev, slot->wp_pin,
> -                                     "mmc_wp")) {
> -                       dev_dbg(&mmc->class_dev, "no WP pin available\n");
> -                       slot->wp_pin = -EBUSY;
> -               }
> +       slot->wp_pin = devm_gpiod_get_optional(&host->pdev->dev, "wp", GPIOD_IN);
> +       if (IS_ERR(slot->wp_pin)) {
> +               dev_dbg(&mmc->class_dev, "no WP pin available\n");
> +               slot->wp_pin = NULL;
>          }
> 
>          host->slot[id] = slot;
> @@ -2312,18 +2307,18 @@ static int atmci_init_slot(struct atmel_mci *host,
>                  return ret;
>          }
> 
> -       if (gpio_is_valid(slot->detect_pin)) {
> +       if (slot->detect_pin) {
>                  timer_setup(&slot->detect_timer, atmci_detect_change, 0);
> 
> -               ret = request_irq(gpio_to_irq(slot->detect_pin),
> +               ret = request_irq(gpiod_to_irq(slot->detect_pin),
>                                  atmci_detect_interrupt,
>                                  IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
>                                  "mmc-detect", slot);
>                  if (ret) {
>                          dev_dbg(&mmc->class_dev,
>                                  "could not request IRQ %d for detect pin\n",
> -                               gpio_to_irq(slot->detect_pin));
> -                       slot->detect_pin = -EBUSY;
> +                               gpiod_to_irq(slot->detect_pin));
> +                       slot->detect_pin = NULL;
>                  }
>          }
> 
> @@ -2342,10 +2337,8 @@ static void atmci_cleanup_slot(struct atmel_mci_slot *slot,
> 
>          mmc_remove_host(slot->mmc);
> 
> -       if (gpio_is_valid(slot->detect_pin)) {
> -               int pin = slot->detect_pin;
> -
> -               free_irq(gpio_to_irq(pin), slot);
> +       if (slot->detect_pin) {
> +               free_irq(gpiod_to_irq(slot->detect_pin), slot);
>                  del_timer_sync(&slot->detect_timer);
>          }
> 
> @@ -2357,22 +2350,6 @@ static int atmci_configure_dma(struct atmel_mci *host)
>   {
>          host->dma.chan = dma_request_chan(&host->pdev->dev, "rxtx");
> 
> -       if (PTR_ERR(host->dma.chan) == -ENODEV) {
> -               struct mci_platform_data *pdata = host->pdev->dev.platform_data;
> -               dma_cap_mask_t mask;
> -
> -               if (!pdata || !pdata->dma_filter)
> -                       return -ENODEV;
> -
> -               dma_cap_zero(mask);
> -               dma_cap_set(DMA_SLAVE, mask);
> -
> -               host->dma.chan = dma_request_channel(mask, pdata->dma_filter,
> -                                                    pdata->dma_slave);
> -               if (!host->dma.chan)
> -                       host->dma.chan = ERR_PTR(-ENODEV);
> -       }
> -
>          if (IS_ERR(host->dma.chan))
>                  return PTR_ERR(host->dma.chan);
> 
> @@ -2450,7 +2427,7 @@ static void atmci_get_cap(struct atmel_mci *host)
> 
>   static int atmci_probe(struct platform_device *pdev)
>   {
> -       struct mci_platform_data        *pdata;
> +       struct mci_slot_pdata           pdata[ATMCI_MAX_NR_SLOTS];
>          struct atmel_mci                *host;
>          struct resource                 *regs;
>          unsigned int                    nr_slots;
> @@ -2460,23 +2437,21 @@ static int atmci_probe(struct platform_device *pdev)
>          regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>          if (!regs)
>                  return -ENXIO;
> -       pdata = pdev->dev.platform_data;
> -       if (!pdata) {
> -               pdata = atmci_of_init(pdev);
> -               if (IS_ERR(pdata)) {
> -                       dev_err(&pdev->dev, "platform data not available\n");
> -                       return PTR_ERR(pdata);
> -               }
> +
> +       host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
> +       if (!host)
> +               return -ENOMEM;
> +
> +       ret = atmci_of_init(pdev, pdata);
> +       if (ret) {
> +               dev_err(&pdev->dev, "error parsing DT\n");
> +               return ret;
>          }
> 
>          irq = platform_get_irq(pdev, 0);
>          if (irq < 0)
>                  return irq;
> 
> -       host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
> -       if (!host)
> -               return -ENOMEM;
> -
>          host->pdev = pdev;
>          spin_lock_init(&host->lock);
>          INIT_LIST_HEAD(&host->queue);
> @@ -2540,16 +2515,16 @@ static int atmci_probe(struct platform_device *pdev)
>          /* We need at least one slot to succeed */
>          nr_slots = 0;
>          ret = -ENODEV;
> -       if (pdata->slot[0].bus_width) {
> -               ret = atmci_init_slot(host, &pdata->slot[0],
> +       if (pdata[0].bus_width) {
> +               ret = atmci_init_slot(host, &pdata[0],
>                                  0, ATMCI_SDCSEL_SLOT_A, ATMCI_SDIOIRQA);
>                  if (!ret) {
>                          nr_slots++;
>                          host->buf_size = host->slot[0]->mmc->max_req_size;
>                  }
>          }
> -       if (pdata->slot[1].bus_width) {
> -               ret = atmci_init_slot(host, &pdata->slot[1],
> +       if (pdata[1].bus_width) {
> +               ret = atmci_init_slot(host, &pdata[1],
>                                  1, ATMCI_SDCSEL_SLOT_B, ATMCI_SDIOIRQB);
>                  if (!ret) {
>                          nr_slots++;
> @@ -2671,7 +2646,7 @@ static struct platform_driver atmci_driver = {
>          .driver         = {
>                  .name           = "atmel_mci",
>                  .probe_type     = PROBE_PREFER_ASYNCHRONOUS,
> -               .of_match_table = of_match_ptr(atmci_dt_ids),
> +               .of_match_table = atmci_dt_ids,
>                  .pm             = &atmci_dev_pm_ops,
>          },
>   };
> diff --git a/include/linux/atmel-mci.h b/include/linux/atmel-mci.h
> deleted file mode 100644
> index 1491af38cc6e..000000000000
> --- a/include/linux/atmel-mci.h
> +++ /dev/null
> @@ -1,46 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -#ifndef __LINUX_ATMEL_MCI_H
> -#define __LINUX_ATMEL_MCI_H
> -
> -#include <linux/types.h>
> -#include <linux/dmaengine.h>
> -
> -#define ATMCI_MAX_NR_SLOTS     2
> -
> -/**
> - * struct mci_slot_pdata - board-specific per-slot configuration
> - * @bus_width: Number of data lines wired up the slot
> - * @detect_pin: GPIO pin wired to the card detect switch
> - * @wp_pin: GPIO pin wired to the write protect sensor
> - * @detect_is_active_high: The state of the detect pin when it is active
> - * @non_removable: The slot is not removable, only detect once
> - *
> - * If a given slot is not present on the board, @bus_width should be
> - * set to 0. The other fields are ignored in this case.
> - *
> - * Any pins that aren't available should be set to a negative value.
> - *
> - * Note that support for multiple slots is experimental -- some cards
> - * might get upset if we don't get the clock management exactly right.
> - * But in most cases, it should work just fine.
> - */
> -struct mci_slot_pdata {
> -       unsigned int            bus_width;
> -       int                     detect_pin;
> -       int                     wp_pin;
> -       bool                    detect_is_active_high;
> -       bool                    non_removable;
> -};
> -
> -/**
> - * struct mci_platform_data - board-specific MMC/SDcard configuration
> - * @dma_slave: DMA slave interface to use in data transfers.
> - * @slot: Per-slot configuration data.
> - */
> -struct mci_platform_data {
> -       void                    *dma_slave;
> -       dma_filter_fn           dma_filter;
> -       struct mci_slot_pdata   slot[ATMCI_MAX_NR_SLOTS];
> -};
> -
> -#endif /* __LINUX_ATMEL_MCI_H */
> --
> 2.39.0
>

On Fri, Jan 27, 2023, at 11:32, Nicolas Ferre wrote:
> Hi Arnd,
>
> On 26/01/2023 at 14:50, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> All Atmel (now Microchip) machines boot using DT, so the
>> old platform_data for this driver is no longer used by any
>> boards.
>> 
>> Removing the pdata probe lets us simplify the GPIO handling
>> with the use of the descriptor API.
>
> Thanks for your patch. I would like to know if it's related to the 
> initiative started by Bala in this series:
>
> https://lore.kernel.org/all/20221226073908.17317-1-balamanikandan.gunasundar@microchip.com/
>
> It's true that it didn't come to a conclusion yet...

I hadn't seen that one, my patch was a somewhat older series to
convert a couple of subsystems over from the old of_get_named_gpio(),
with no special interest in this platform.

It looks like the patches are fairly similar, with two differences
I can see immediately:

- I use the normal devm_gpiod_get_optional(), while Bala uses
  the fwnode variant that should not be needed here since the
  fwnode is the one for the platform device itself.
- I use the normal gpiod_get_value(), which will handle polarity
  as specified in DT, while Bala's patch uses gpiod_get_raw_value().
  The difference is what happens when the GPIO_ACTIVE_LOW flag
  is set in the DT, and the possible combinations with the
  "cd-inverted" flag. I did not test my version, so I assume
  Bala is correct here, but it would be good to review this
  carefully either way.

     Arnd