Re: [PATCH] staging: iio: ad2s1210: Switch to the gpio descriptor interface

From: Slawomir Stepien
Date: Sun Oct 21 2018 - 04:31:34 EST

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In reply to: Nishad Kamdar: "[PATCH] staging: iio: ad2s1210: Switch to the gpio descriptor interface"
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On paÅ 21, 2018 11:49, Nishad Kamdar wrote:
> Use the gpiod interface instead of the deprecated old non-descriptor
> interface.

Hi!

See my comments below.

> Signed-off-by: Nishad Kamdar <nishadkamdar@xxxxxxxxx>
> ---
> drivers/staging/iio/resolver/ad2s1210.c | 110 +++++++++++++++---------
> drivers/staging/iio/resolver/ad2s1210.h | 3 -
> 2 files changed, 71 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
> index ac13b99bd9cb..ed372a5f9130 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.c
> +++ b/drivers/staging/iio/resolver/ad2s1210.c
> @@ -15,7 +15,7 @@
> #include <linux/slab.h>
> #include <linux/sysfs.h>
> #include <linux/delay.h>
> -#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/module.h>
>
> #include <linux/iio/iio.h>
> @@ -73,6 +73,11 @@ struct ad2s1210_state {
> const struct ad2s1210_platform_data *pdata;
> struct mutex lock;
> struct spi_device *sdev;
> + struct gpio_desc *sample;
> + struct gpio_desc *a0;
> + struct gpio_desc *a1;
> + struct gpio_desc *res0;
> + struct gpio_desc *res1;
> unsigned int fclkin;
> unsigned int fexcit;
> bool hysteresis;
> @@ -91,8 +96,8 @@ static const int ad2s1210_mode_vals[4][2] = {
> static inline void ad2s1210_set_mode(enum ad2s1210_mode mode,
> struct ad2s1210_state *st)
> {
> - gpio_set_value(st->pdata->a[0], ad2s1210_mode_vals[mode][0]);
> - gpio_set_value(st->pdata->a[1], ad2s1210_mode_vals[mode][1]);
> + gpiod_set_value(st->a0, ad2s1210_mode_vals[mode][0]);
> + gpiod_set_value(st->a1, ad2s1210_mode_vals[mode][1]);
> st->mode = mode;
> }
>
> @@ -152,8 +157,8 @@ int ad2s1210_update_frequency_control_word(struct ad2s1210_state *st)
>
> static unsigned char ad2s1210_read_resolution_pin(struct ad2s1210_state *st)
> {
> - int resolution = (gpio_get_value(st->pdata->res[0]) << 1) |
> - gpio_get_value(st->pdata->res[1]);
> + int resolution = (gpiod_get_value(st->res0) << 1) |
> + gpiod_get_value(st->res1);
>
> return ad2s1210_resolution_value[resolution];
> }
> @@ -164,10 +169,10 @@ static const int ad2s1210_res_pins[4][2] = {
>
> static inline void ad2s1210_set_resolution_pin(struct ad2s1210_state *st)
> {
> - gpio_set_value(st->pdata->res[0],
> - ad2s1210_res_pins[(st->resolution - 10) / 2][0]);
> - gpio_set_value(st->pdata->res[1],
> - ad2s1210_res_pins[(st->resolution - 10) / 2][1]);
> + gpiod_set_value(st->res0,
> + ad2s1210_res_pins[(st->resolution - 10) / 2][0]);
> + gpiod_set_value(st->res1,
> + ad2s1210_res_pins[(st->resolution - 10) / 2][1]);
> }
>
> static inline int ad2s1210_soft_reset(struct ad2s1210_state *st)
> @@ -401,15 +406,15 @@ static ssize_t ad2s1210_clear_fault(struct device *dev,
> int ret;
>
> mutex_lock(&st->lock);
> - gpio_set_value(st->pdata->sample, 0);
> + gpiod_set_value(st->sample, 0);
> /* delay (2 * tck + 20) nano seconds */
> udelay(1);
> - gpio_set_value(st->pdata->sample, 1);
> + gpiod_set_value(st->sample, 1);
> ret = ad2s1210_config_read(st, AD2S1210_REG_FAULT);
> if (ret < 0)
> goto error_ret;
> - gpio_set_value(st->pdata->sample, 0);
> - gpio_set_value(st->pdata->sample, 1);
> + gpiod_set_value(st->sample, 0);
> + gpiod_set_value(st->sample, 1);
> error_ret:
> mutex_unlock(&st->lock);
>
> @@ -466,7 +471,7 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
> s16 vel;
>
> mutex_lock(&st->lock);
> - gpio_set_value(st->pdata->sample, 0);
> + gpiod_set_value(st->sample, 0);
> /* delay (6 * tck + 20) nano seconds */
> udelay(1);
>
> @@ -512,7 +517,7 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
> }
>
> error_ret:
> - gpio_set_value(st->pdata->sample, 1);
> + gpiod_set_value(st->sample, 1);
> /* delay (2 * tck + 20) nano seconds */
> udelay(1);
> mutex_unlock(&st->lock);
> @@ -628,32 +633,59 @@ static const struct iio_info ad2s1210_info = {
> .attrs = &ad2s1210_attribute_group,
> };
>
> -static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
> +static int ad2s1210_setup_gpios(struct spi_device *spi,
> + struct ad2s1210_state *st)

This change is not needed. The st has the spi_device inside. Use container_of()
macro here.

> {
> - unsigned long flags = st->pdata->gpioin ? GPIOF_DIR_IN : GPIOF_DIR_OUT;
> - struct gpio ad2s1210_gpios[] = {
> - { st->pdata->sample, GPIOF_DIR_IN, "sample" },
> - { st->pdata->a[0], flags, "a0" },
> - { st->pdata->a[1], flags, "a1" },
> - { st->pdata->res[0], flags, "res0" },
> - { st->pdata->res[0], flags, "res1" },
> - };
> + int ret = 0;
> + unsigned long flags = st->pdata->gpioin ? GPIOD_IN : GPIOD_OUT_LOW;
> +
> + st->sample = devm_gpiod_get(&spi->dev, "sample", GPIOD_IN);
> + if (IS_ERR(st->sample)) {
> + ret = PTR_ERR(st->sample);
> + dev_err(&spi->dev, "Failed to request sample GPIO: %d\n",
> + ret);
> + return ret;
> + }
> + st->a0 = devm_gpiod_get(&spi->dev, "a0", flags);
> + if (IS_ERR(st->a0)) {
> + ret = PTR_ERR(st->a0);
> + dev_err(&spi->dev, "Failed to request a0 GPIO: %d\n",
> + ret);
> + return ret;
> + }
> + st->a1 = devm_gpiod_get(&spi->dev, "a1", flags);
> + if (IS_ERR(st->a1)) {
> + ret = PTR_ERR(st->a1);
> + dev_err(&spi->dev, "Failed to request a1 GPIO: %d\n",
> + ret);
> + return ret;
> + }
> + st->res0 = devm_gpiod_get(&spi->dev, "res0", flags);
> + if (IS_ERR(st->res0)) {
> + ret = PTR_ERR(st->res0);
> + dev_err(&spi->dev, "Failed to request res0 GPIO: %d\n",
> + ret);
> + return ret;
> + }
> + st->res1 = devm_gpiod_get(&spi->dev, "res1", flags);
> + if (IS_ERR(st->res1)) {
> + ret = PTR_ERR(st->res1);
> + dev_err(&spi->dev, "Failed to request res1 GPIO: %d\n",
> + ret);
> + return ret;
> + }

To reduce the redundant code here, create an array of structs. The struct will
have a pointer to gpio_desc, name of the gpio and the gpios' flags. Then you can
use for loop to get all the needed gpios:

for (l = 0; l < ARRAY_SIZE(str); l++) {
str[l].ptr = devm_gpiod_get(&spi->dev, str[l].name, str[l].flags);
if (IS_ERR(str[l].res1)) {
...
}
}

> - return gpio_request_array(ad2s1210_gpios, ARRAY_SIZE(ad2s1210_gpios));
> + return ret;
> }
>
> -static void ad2s1210_free_gpios(struct ad2s1210_state *st)
> +static void ad2s1210_free_gpios(struct spi_device *spi,
> + struct ad2s1210_state *st)
> {
> - unsigned long flags = st->pdata->gpioin ? GPIOF_DIR_IN : GPIOF_DIR_OUT;
> - struct gpio ad2s1210_gpios[] = {
> - { st->pdata->sample, GPIOF_DIR_IN, "sample" },
> - { st->pdata->a[0], flags, "a0" },
> - { st->pdata->a[1], flags, "a1" },
> - { st->pdata->res[0], flags, "res0" },
> - { st->pdata->res[0], flags, "res1" },
> - };
> -
> - gpio_free_array(ad2s1210_gpios, ARRAY_SIZE(ad2s1210_gpios));
> + devm_gpiod_put(&spi->dev, st->sample);
> + devm_gpiod_put(&spi->dev, st->a0);
> + devm_gpiod_put(&spi->dev, st->a1);
> + devm_gpiod_put(&spi->dev, st->res0);
> + devm_gpiod_put(&spi->dev, st->res1);
> }

This whole function ad2s1210_free_gpios is not needed anymore because you are
using the devm API (it's called from probe and remove, so you are safe).

> static int ad2s1210_probe(struct spi_device *spi)
> @@ -670,7 +702,7 @@ static int ad2s1210_probe(struct spi_device *spi)
> return -ENOMEM;
> st = iio_priv(indio_dev);
> st->pdata = spi->dev.platform_data;
> - ret = ad2s1210_setup_gpios(st);
> + ret = ad2s1210_setup_gpios(spi, st);
> if (ret < 0)
> return ret;
>
> @@ -702,7 +734,7 @@ static int ad2s1210_probe(struct spi_device *spi)
> return 0;
>
> error_free_gpios:
> - ad2s1210_free_gpios(st);
> + ad2s1210_free_gpios(spi, st);
> return ret;
> }
>
> @@ -711,7 +743,7 @@ static int ad2s1210_remove(struct spi_device *spi)
> struct iio_dev *indio_dev = spi_get_drvdata(spi);
>
> iio_device_unregister(indio_dev);
> - ad2s1210_free_gpios(iio_priv(indio_dev));
> + ad2s1210_free_gpios(spi, iio_priv(indio_dev));
>
> return 0;
> }
> diff --git a/drivers/staging/iio/resolver/ad2s1210.h b/drivers/staging/iio/resolver/ad2s1210.h
> index e9b2147701fc..63d479b20a6c 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.h
> +++ b/drivers/staging/iio/resolver/ad2s1210.h
> @@ -12,9 +12,6 @@
> #define _AD2S1210_H
>
> struct ad2s1210_platform_data {
> - unsigned int sample;
> - unsigned int a[2];
> - unsigned int res[2];
> bool gpioin;
> };
> #endif /* _AD2S1210_H */

--
Slawomir Stepien

Next message: Pavel Machek: "Re: [PATCH v2 2/3] leds: upboard: Add LED support"
Previous message: Theodore Y. Ts'o: "Re: [Ksummit-discuss] [PATCH 6/7] Code of Conduct: Change the contact email address"
In reply to: Nishad Kamdar: "[PATCH] staging: iio: ad2s1210: Switch to the gpio descriptor interface"
Next in thread: Slawomir Stepien: "Re: [PATCH] staging: iio: ad2s1210: Switch to the gpio descriptor interface"
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