linux-kernel - Re: [PATCH 18/21] nfc: s3fwrn5: convert to gpio descriptors

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Message-ID: <bkvnzaipmkiz7lkh5p35pqmdtlcwnm5j5snyc7g5umfxm3io6j@dqhetenn2zm2>
Date: Mon, 11 Aug 2025 15:08:58 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Arnd Bergmann <arnd@...nel.org>
Cc: Bartosz Golaszewski <brgl@...ev.pl>, 
	Linus Walleij <linus.walleij@...aro.org>, linux-gpio@...r.kernel.org, 
	Krzysztof Kozlowski <krzk@...nel.org>, Arnd Bergmann <arnd@...db.de>, 
	Sumanth Gavini <sumanth.gavini@...oo.com>, Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 18/21] nfc: s3fwrn5: convert to gpio descriptors

Hi Arnd,

On Fri, Aug 08, 2025 at 05:18:02PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> There is no need for this driver to still use the legacy interfaces,
> so convert all the legacy calls into their modern equivalents.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/nfc/s3fwrn5/i2c.c        | 42 +++++++++-----------------------
>  drivers/nfc/s3fwrn5/phy_common.c | 12 ++++-----
>  drivers/nfc/s3fwrn5/phy_common.h |  4 +--
>  drivers/nfc/s3fwrn5/uart.c       | 30 ++++++-----------------
>  4 files changed, 28 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/nfc/s3fwrn5/i2c.c b/drivers/nfc/s3fwrn5/i2c.c
> index 110d086cfe5b..411be709b397 100644
> --- a/drivers/nfc/s3fwrn5/i2c.c
> +++ b/drivers/nfc/s3fwrn5/i2c.c
> @@ -8,7 +8,7 @@
>  
>  #include <linux/clk.h>
>  #include <linux/i2c.h>
> -#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/delay.h>
>  #include <linux/of_gpio.h>
>  #include <linux/of_irq.h>
> @@ -149,29 +149,22 @@ static irqreturn_t s3fwrn5_i2c_irq_thread_fn(int irq, void *phy_id)
>  static int s3fwrn5_i2c_parse_dt(struct i2c_client *client)
>  {
>  	struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);
> -	struct device_node *np = client->dev.of_node;
> +	struct device *dev = &client->dev;
>  
> -	if (!np)
> -		return -ENODEV;
> -
> -	phy->common.gpio_en = of_get_named_gpio(np, "en-gpios", 0);
> -	if (!gpio_is_valid(phy->common.gpio_en)) {
> +	phy->common.gpio_en = devm_gpiod_get(dev, "en", GPIOD_OUT_HIGH);
> +	if (IS_ERR(phy->common.gpio_en)) {
>  		/* Support also deprecated property */
> -		phy->common.gpio_en = of_get_named_gpio(np,
> -							"s3fwrn5,en-gpios",
> -							0);
> -		if (!gpio_is_valid(phy->common.gpio_en))
> -			return -ENODEV;
> +		phy->common.gpio_en = devm_gpiod_get(dev, "s3fwrn5,en", GPIOD_OUT_HIGH);
> +		if (IS_ERR(phy->common.gpio_en))
> +			return PTR_ERR(phy->common.gpio_en);
>  	}

Should be GPIOD_OUT_LOW or ASIS.

>  
> -	phy->common.gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
> -	if (!gpio_is_valid(phy->common.gpio_fw_wake)) {
> +	phy->common.gpio_fw_wake = devm_gpiod_get(dev, "wake", GPIOD_OUT_LOW);
> +	if (IS_ERR(phy->common.gpio_fw_wake)) {
>  		/* Support also deprecated property */
> -		phy->common.gpio_fw_wake = of_get_named_gpio(np,
> -							     "s3fwrn5,fw-gpios",
> -							     0);
> -		if (!gpio_is_valid(phy->common.gpio_fw_wake))
> -			return -ENODEV;
> +		phy->common.gpio_fw_wake = devm_gpiod_get(dev, "s3fwrn5,fw", GPIOD_OUT_LOW);
> +		if (IS_ERR(phy->common.gpio_fw_wake))
> +			return PTR_ERR(phy->common.gpio_en);
>  	}
>  
>  	return 0;
> @@ -197,17 +190,6 @@ static int s3fwrn5_i2c_probe(struct i2c_client *client)
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = devm_gpio_request_one(&phy->i2c_dev->dev, phy->common.gpio_en,
> -				    GPIOF_OUT_INIT_HIGH, "s3fwrn5_en");
> -	if (ret < 0)
> -		return ret;
> -
> -	ret = devm_gpio_request_one(&phy->i2c_dev->dev,
> -				    phy->common.gpio_fw_wake,
> -				    GPIOF_OUT_INIT_LOW, "s3fwrn5_fw_wake");
> -	if (ret < 0)
> -		return ret;
> -
>  	/*
>  	 * S3FWRN5 depends on a clock input ("XI" pin) to function properly.
>  	 * Depending on the hardware configuration this could be an always-on
> diff --git a/drivers/nfc/s3fwrn5/phy_common.c b/drivers/nfc/s3fwrn5/phy_common.c
> index deb2c039f0fd..e802b4e609c8 100644
> --- a/drivers/nfc/s3fwrn5/phy_common.c
> +++ b/drivers/nfc/s3fwrn5/phy_common.c
> @@ -8,7 +8,7 @@
>   * Bongsu Jeon <bongsu.jeon@...sung.com>
>   */
>  
> -#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/delay.h>
>  #include <linux/module.h>
>  
> @@ -19,7 +19,7 @@ void s3fwrn5_phy_set_wake(void *phy_id, bool wake)
>  	struct phy_common *phy = phy_id;
>  
>  	mutex_lock(&phy->mutex);
> -	gpio_set_value(phy->gpio_fw_wake, wake);
> +	gpiod_set_value(phy->gpio_fw_wake, wake);
>  	if (wake)
>  		msleep(S3FWRN5_EN_WAIT_TIME);
>  	mutex_unlock(&phy->mutex);
> @@ -33,14 +33,14 @@ bool s3fwrn5_phy_power_ctrl(struct phy_common *phy, enum s3fwrn5_mode mode)
>  
>  	phy->mode = mode;
>  
> -	gpio_set_value(phy->gpio_en, 1);
> -	gpio_set_value(phy->gpio_fw_wake, 0);
> +	gpiod_set_value(phy->gpio_en, 1);
> +	gpiod_set_value(phy->gpio_fw_wake, 0);
>  	if (mode == S3FWRN5_MODE_FW)
> -		gpio_set_value(phy->gpio_fw_wake, 1);
> +		gpiod_set_value(phy->gpio_fw_wake, 1);
>  
>  	if (mode != S3FWRN5_MODE_COLD) {
>  		msleep(S3FWRN5_EN_WAIT_TIME);
> -		gpio_set_value(phy->gpio_en, 0);
> +		gpiod_set_value(phy->gpio_en, 0);
>  		msleep(S3FWRN5_EN_WAIT_TIME);

The GPIO is describe as "active low" in DTS:

arch/arm64/boot/dts/exynos/exynos5433-tm2-common.dtsi

So here you are leaving the chip disabled. You need to use logical
polarity.

Thanks.

-- 
Dmitry