Re: [PATCH v6 1/3] staging: iio: ad2s1210: Switch to the gpio descriptor interface

From: Nishad Kamdar
Date: Sun Oct 28 2018 - 16:42:22 EST

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In reply to: Jonathan Cameron: "Re: [PATCH v6 1/3] staging: iio: ad2s1210: Switch to the gpio descriptor interface"
Next in thread: Nishad Kamdar: "[PATCH v6 2/3] staging: iio: ad2s1210: Add device tree table."
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On Sun, Oct 28, 2018 at 02:36:07PM +0000, Jonathan Cameron wrote:
> On Sun, 28 Oct 2018 13:21:25 +0530
> Nishad Kamdar <nishadkamdar@xxxxxxxxx> wrote:
>
> > Use the gpiod interface instead of the deprecated old non-descriptor
> > interface.
> >
> > Signed-off-by: Nishad Kamdar <nishadkamdar@xxxxxxxxx>
> Hi Nishad,
>
> Sorry it took me most of the week to get to this. It's a trade off when you
> want to make fast progress, but I would suggest always leaving a few days
> between patches to see if there are other review comments coming in.
>

Ok, I'll keep that in mind.
> I don't particularly mind myself (as I'm very good at ignoring older versions ;)
> but I do feel some time got wasted here on your part.
>
> Anyhow, what you have here is correct but the drive to get things as a nice
> array has lead to a weird mixture of being all array based and not being at all.
> Some suggestions in line that will hopefully tidy this up for you.
>
> I'm basically suggesting adding a layer of indirection where you don't currently
> have one (on the actual reads and writes) so that you get more consistency
> with the setup code rather than adding a lot of fiddly indirection just in
> the setup code.
>
> Note, what I've given is very much meant to be an illustration. It's probably
> full of bugs and silly naming etc, so don't take it as being right!
>
> Jonathan
>
> > ---
> > drivers/staging/iio/resolver/ad2s1210.c | 92 ++++++++++++++-----------
> > drivers/staging/iio/resolver/ad2s1210.h | 3 -
> > 2 files changed, 50 insertions(+), 45 deletions(-)
> >
> > diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
> > index ac13b99bd9cb..93c3c70ce62e 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>
> > @@ -69,10 +69,21 @@ enum ad2s1210_mode {
> >
> > static const unsigned int ad2s1210_resolution_value[] = { 10, 12, 14, 16 };
> >
> > +struct ad2s1210_gpio {
> > + struct gpio_desc **ptr;
> > + const char *name;
> > + unsigned long flags;
> > +};
> > +
> > struct ad2s1210_state {
> > const struct ad2s1210_platform_data *pdata;
> > struct mutex lock;
> > struct spi_device *sdev;
>
> With the setup below this becomes
> struct gpio_desc *gpios[5];
>
> > + 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 +102,8 @@ 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 +163,8 @@ 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 +175,10 @@ 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 +412,15 @@ 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 +477,7 @@ 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 +523,7 @@ 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);
>
> With the below this becomes
> gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
>
> > /* delay (2 * tck + 20) nano seconds */
> > udelay(1);
> > mutex_unlock(&st->lock);
> > @@ -630,30 +641,32 @@ static const struct iio_info ad2s1210_info = {
> >
> > static int ad2s1210_setup_gpios(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" },
> > + int ret, i;
> > + struct spi_device *spi = st->sdev;
> > + struct ad2s1210_gpio *pin;
> > + unsigned long flags = st->pdata->gpioin ? GPIOD_IN : GPIOD_OUT_LOW;
>
> So talk me through what is going on here? All of a and res are controlled
> by this one parameter?
>

Yes. This was how the original code was. I kept it as it is.
> > +
> > + struct ad2s1210_gpio gpios[] = {
> > + { .ptr = &st->sample, .name = "sample", .flags = GPIOD_IN },
> > + { .ptr = &st->a0, .name = "a0", .flags = flags },
> > + { .ptr = &st->a1, .name = "a1", .flags = flags },
> > + { .ptr = &st->res0, .name = "res0", .flags = flags },
> > + { .ptr = &st->res1, .name = "res1", .flags = flags },
>
> To my eye, there are two sets of gpios in here. They were originally handled
> like that st->pdata->a[0] etc, and it would be sensible to continue doing so.
>
> Actually I don't really like the indirection at all. Why not have
> a simple enum indexing the gpios and then have a single array in st for them all?
>
> enum ad2s1210_gpios {
> AD2S1210_SAMPLE,
> AD2S1210_A0,
> AD2S1210_A1,
> AD2S1210_RES0,
> AD2S1210_RES1,
> };
>
> Then have two constant versions of the above structure (shrunk a bit) that you
> pick from depending on the flag.
>
> static const struct ad2s1210_gpio gpios_gpioin[] = {
> [AD2S1210_SAMPLE] = { .name = "sample", .flags = GPIOD_IN, },
> [AD2S1210_A0] = { .name = "a0", .flags = GPIOD_IN, },
> [AD2S1210_A1] = { .name = "a1", .flags = GPIOD_IN, },
> [AD2S1210_RES0] = { .name = "res0", .flags = GPIOD_IN, },
> [AD2S1210_RES1] = { .name = "res1", .flags = GPIOD_IN, },
> };
>
> static const struct ad2s1210_gpio gpios_gpioout[] = {
> [AD2S1210_SAMPLE] = { .name = "sample", .flags = GPIOD_IN, },
> [AD2S1210_A0] = { .name = "a0", .flags = GPIOD_OUT, },
> [AD2S1210_A1] = { .name = "a1", .flags = GPIOD_OUT, },
> [AD2S1210_RES0] = { .name = "res0", .flags = GPIOD_OUT, },
> [AD2S1210_RES1] = { .name = "res1", .flags = GPIOD_OUT, },
> };
>
>
> static int ad2s1210_setup_gpios(struct ad2s1210_state *st, bool gpioin)
> {
> //note my naming is awful so do this better than I have ;)
> struct ad2s1201_gpio *pin = gpioin ? &gpios_gpioin[0] : &gpios_gpiout[0];
> int i;
>
>
> for (i = 0; i < ARRAY_SIZE(gpios_gpioin); i++) {
> st->gpios[i] = devm_gpiod_get(&spi->dev, pin[i]->name, pin[i]->flags);
> if (IS_ERR(st->gpios[i])) {
> ret = PTR_ERR(st->gpios[i]);
> dev_err(&spi->dev,
> "ad2s1210: failed to request %s GPIO: %d\n",
> pin->name, ret);
> return ret;
> }
> }
>
> return 0;
> }
>
> > };
> >
> > - return gpio_request_array(ad2s1210_gpios, ARRAY_SIZE(ad2s1210_gpios));
> > -}
> > -
> > -static void ad2s1210_free_gpios(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" },
> > - };
> > + for (i = 0; i < ARRAY_SIZE(gpios); i++) {
> > + pin = &gpios[i];
> > + *pin->ptr = devm_gpiod_get(&spi->dev, pin->name, pin->flags);
> > + if (IS_ERR(*pin->ptr)) {
> > + ret = PTR_ERR(*pin->ptr);
> > + dev_err(&spi->dev,
> > + "ad2s1210: failed to request %s GPIO: %d\n",
> > + pin->name, ret);
> > + return ret;
> > + }
> > + }
> >
> > - gpio_free_array(ad2s1210_gpios, ARRAY_SIZE(ad2s1210_gpios));
> > + return 0;
> > }
> >
> > static int ad2s1210_probe(struct spi_device *spi)
> > @@ -692,7 +705,7 @@ static int ad2s1210_probe(struct spi_device *spi)
> >
> > ret = iio_device_register(indio_dev);
> > if (ret)
> > - goto error_free_gpios;
> > + return ret;
> >
> > st->fclkin = spi->max_speed_hz;
> > spi->mode = SPI_MODE_3;
> > @@ -700,10 +713,6 @@ static int ad2s1210_probe(struct spi_device *spi)
> > ad2s1210_initial(st);
> >
> > return 0;
> > -
> > -error_free_gpios:
> > - ad2s1210_free_gpios(st);
> > - return ret;
> > }
> >
> > static int ad2s1210_remove(struct spi_device *spi)
> > @@ -711,7 +720,6 @@ 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));
> >
> > 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 */
>

ok, I'll make the changes.

Thanks for thre review.

regards,
Nishad

Next message: Stefan Wahren: "Re: [PATCH RFC 09/18] staging: vchiq_core: do not initialize semaphores twice"
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In reply to: Jonathan Cameron: "Re: [PATCH v6 1/3] staging: iio: ad2s1210: Switch to the gpio descriptor interface"
Next in thread: Nishad Kamdar: "[PATCH v6 2/3] staging: iio: ad2s1210: Add device tree table."
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