[v3,1/2] mmc: atmel-mci: Convert to gpio descriptors

Replace the legacy GPIO APIs with gpio descriptor consumer interface.

To maintain backward compatibility, we rely on the "cd-inverted"
property to manage the invertion flag instead of GPIO property.

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/mmc/host/atmel-mci.c | 78 +++++++++++++++++-------------------
 include/linux/atmel-mci.h    |  4 +-
 2 files changed, 39 insertions(+), 43 deletions(-)

On 26/12/2022 08:39, Balamanikandan Gunasundar wrote:
> Replace the legacy GPIO APIs with gpio descriptor consumer interface.
> 
> To maintain backward compatibility, we rely on the "cd-inverted"
> property to manage the invertion flag instead of GPIO property.
> 
> Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
Reviewed-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
>   drivers/mmc/host/atmel-mci.c | 78 +++++++++++++++++-------------------
>   include/linux/atmel-mci.h    |  4 +-
>   2 files changed, 39 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index 67b2cd166e56..6ab43733ba9f 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -11,7 +11,6 @@
>   #include <linux/dmaengine.h>
>   #include <linux/dma-mapping.h>
>   #include <linux/err.h>
> -#include <linux/gpio.h>
>   #include <linux/init.h>
>   #include <linux/interrupt.h>
>   #include <linux/io.h>
> @@ -19,7 +18,8 @@
>   #include <linux/module.h>
>   #include <linux/of.h>
>   #include <linux/of_device.h>
> -#include <linux/of_gpio.h>
> +#include <linux/irq.h>
> +#include <linux/gpio/consumer.h>
>   #include <linux/platform_device.h>
>   #include <linux/scatterlist.h>
>   #include <linux/seq_file.h>
> @@ -389,8 +389,8 @@ 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;
> @@ -638,7 +638,10 @@ atmci_of_init(struct platform_device *pdev)
>   			pdata->slot[slot_id].bus_width = 1;
>   
>   		pdata->slot[slot_id].detect_pin =
> -			of_get_named_gpio(cnp, "cd-gpios", 0);
> +			devm_fwnode_gpiod_get(&pdev->dev, of_fwnode_handle(cnp),
> +					      "cd", GPIOD_IN, "cd-gpios");
> +		if (IS_ERR(pdata->slot[slot_id].detect_pin))
> +			pdata->slot[slot_id].detect_pin = NULL;
>   
>   		pdata->slot[slot_id].detect_is_active_high =
>   			of_property_read_bool(cnp, "cd-inverted");
> @@ -647,7 +650,10 @@ atmci_of_init(struct platform_device *pdev)
>   			of_property_read_bool(cnp, "non-removable");
>   
>   		pdata->slot[slot_id].wp_pin =
> -			of_get_named_gpio(cnp, "wp-gpios", 0);
> +			devm_fwnode_gpiod_get(&pdev->dev, of_fwnode_handle(cnp),
> +					      "wp", GPIOD_IN, "wp-gpios");
> +		if (IS_ERR(pdata->slot[slot_id].wp_pin))
> +			pdata->slot[slot_id].wp_pin = NULL;
>   	}
>   
>   	return pdata;
> @@ -1511,8 +1517,8 @@ 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");
>   	}
> @@ -1525,8 +1531,8 @@ 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_raw_value(slot->detect_pin) ^
>   			    slot->detect_is_active_high);
>   		dev_dbg(&mmc->class_dev, "card is %spresent\n",
>   				present ? "" : "not ");
> @@ -1639,8 +1645,8 @@ 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_raw_value(slot->detect_pin) ^
>   		    slot->detect_is_active_high);
>   	present_old = test_bit(ATMCI_CARD_PRESENT, &slot->flags);
>   
> @@ -2241,9 +2247,9 @@ static int atmci_init_slot(struct atmel_mci *host,
>   	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,
> +		id, slot_data->bus_width, desc_to_gpio(slot_data->detect_pin),
>   		slot_data->detect_is_active_high ? "true" : "false",
> -		slot_data->wp_pin);
> +		desc_to_gpio(slot_data->wp_pin));
>   
>   	mmc->ops = &atmci_ops;
>   	mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
> @@ -2279,51 +2285,43 @@ 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) {
> +	if (slot->detect_pin) {
> +		if (gpiod_get_raw_value(slot->detect_pin) ^
> +		    slot->detect_is_active_high) {
>   			clear_bit(ATMCI_CARD_PRESENT, &slot->flags);
>   		}
> +	} else {
> +		dev_dbg(&mmc->class_dev, "no detect pin available\n");
>   	}
>   
> -	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;
> -		}
> -	}
> +	if (!slot->wp_pin)
> +		dev_dbg(&mmc->class_dev, "no WP pin available\n");
>   
>   	host->slot[id] = slot;
>   	mmc_regulator_get_supply(mmc);
> -	mmc_pwrseq_alloc(slot->mmc);
>   	mmc_add_host(mmc);
>   
> -	if (gpio_is_valid(slot->detect_pin)) {
> +	if (slot->detect_pin) {
>   		int ret;
>   
>   		timer_setup(&slot->detect_timer, atmci_detect_change, 0);
>   
> -		ret = request_irq(gpio_to_irq(slot->detect_pin),
> -				atmci_detect_interrupt,
> -				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
> -				"mmc-detect", slot);
> +		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 +2340,8 @@ 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);
>   	}
>   
> diff --git a/include/linux/atmel-mci.h b/include/linux/atmel-mci.h
> index 1491af38cc6e..017e7d8f6126 100644
> --- a/include/linux/atmel-mci.h
> +++ b/include/linux/atmel-mci.h
> @@ -26,8 +26,8 @@
>    */
>   struct mci_slot_pdata {
>   	unsigned int		bus_width;
> -	int			detect_pin;
> -	int			wp_pin;
> +	struct gpio_desc        *detect_pin;
> +	struct gpio_desc	*wp_pin;
>   	bool			detect_is_active_high;
>   	bool			non_removable;
>   };

Hi Balamanikandan,

thanks for your patch!

On Mon, Dec 26, 2022 at 8:39 AM Balamanikandan Gunasundar
<balamanikandan.gunasundar@microchip.com> wrote:

> Replace the legacy GPIO APIs with gpio descriptor consumer interface.
>
> To maintain backward compatibility, we rely on the "cd-inverted"
> property to manage the invertion flag instead of GPIO property.
>
> Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>

Overall this looks really nice! I thought about converting this driver
but was a bit afraid of doing mistakes since it was a bit elaborate.
Nice that you use fwnode accessors!

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Improvement to consider (can also be a separate patch):

> +       if (slot->detect_pin) {
> +               present = !(gpiod_get_raw_value(slot->detect_pin) ^
>                             slot->detect_is_active_high);

Normally we contain all this active low/high mess in mmc_of_parse(),
but I guess this doesn't work here because the of node is different
from the device :P

Since the code says *explicitly* "active high" not "inverted" as the
core code parses it, could you try just push this to gpiolib like
we usually do, by deleting the detect_is_active_high stuff and
just apply a patch like this?

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 4fff7258ee41..5979c9a75cf9 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -199,7 +199,9 @@ static void of_gpio_set_polarity_by_property(const
struct device_node *np,
                { "fsl,imx8mm-pcie", "reset-gpio", "reset-gpio-active-high" },
                { "fsl,imx8mp-pcie", "reset-gpio", "reset-gpio-active-high" },
 #endif
-
+#if IS_ENABLED(CONFIG_MMC_ATMELMCI)
+               { "atmel,hsmci", "cd-gpios", "cd-inverted" },
+#endif
                /*
                 * The regulator GPIO handles are specified such that the
                 * presence or absence of "enable-active-high" solely controls

(It's fine to include in your MMC patch if some GPIO maintainer like
me ACK it.)

Yours,
Linus Walleij

On Thu, 29 Dec 2022 at 01:23, Linus Walleij <linus.walleij@linaro.org> wrote:
>
> Hi Balamanikandan,
>
> thanks for your patch!
>
> On Mon, Dec 26, 2022 at 8:39 AM Balamanikandan Gunasundar
> <balamanikandan.gunasundar@microchip.com> wrote:
>
> > Replace the legacy GPIO APIs with gpio descriptor consumer interface.
> >
> > To maintain backward compatibility, we rely on the "cd-inverted"
> > property to manage the invertion flag instead of GPIO property.
> >
> > Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
>
> Overall this looks really nice! I thought about converting this driver
> but was a bit afraid of doing mistakes since it was a bit elaborate.
> Nice that you use fwnode accessors!
>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>

Linus, thanks for helping out by reviewing this!

>
> Improvement to consider (can also be a separate patch):

I tried to apply the $subject patch as is, but it failed. It needs to
be rebased on top of my latest next branch. Please re-spin and if
possible, consider incorporating Linus's suggestions too as part of
the series.

Kind regards
Uffe



>
> > +       if (slot->detect_pin) {
> > +               present = !(gpiod_get_raw_value(slot->detect_pin) ^
> >                             slot->detect_is_active_high);
>
> Normally we contain all this active low/high mess in mmc_of_parse(),
> but I guess this doesn't work here because the of node is different
> from the device :P
>
> Since the code says *explicitly* "active high" not "inverted" as the
> core code parses it, could you try just push this to gpiolib like
> we usually do, by deleting the detect_is_active_high stuff and
> just apply a patch like this?
>
> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
> index 4fff7258ee41..5979c9a75cf9 100644
> --- a/drivers/gpio/gpiolib-of.c
> +++ b/drivers/gpio/gpiolib-of.c
> @@ -199,7 +199,9 @@ static void of_gpio_set_polarity_by_property(const
> struct device_node *np,
>                 { "fsl,imx8mm-pcie", "reset-gpio", "reset-gpio-active-high" },
>                 { "fsl,imx8mp-pcie", "reset-gpio", "reset-gpio-active-high" },
>  #endif
> -
> +#if IS_ENABLED(CONFIG_MMC_ATMELMCI)
> +               { "atmel,hsmci", "cd-gpios", "cd-inverted" },
> +#endif
>                 /*
>                  * The regulator GPIO handles are specified such that the
>                  * presence or absence of "enable-active-high" solely controls
>
> (It's fine to include in your MMC patch if some GPIO maintainer like
> me ACK it.)
>
> Yours,
> Linus Walleij