Re: [PATCH v3 13/27] staging: iio: resolver: ad2s1210: rework gpios

Jonathan Cameron
2023-09-30T14:55:38Z

On Fri, 29 Sep 2023 12:23:18 -0500
David Lechner <dlechner@baylibre.com> wrote:

> From: David Lechner <david@lechnology.com>
>
> From: David Lechner <dlechner@baylibre.com>
>
> - Remove "adi," prefix from gpio names.
> - Sample gpio is now expected to be active low.
> - Convert A0 and A1 gpios to "mode-gpios" gpio array.
> - Convert RES0 and RES1 gpios to "resolution-gpios" gpio array.
> - Remove extraneous lookup tables.
> - Remove unused mode field from state struct.
> - Swap argument order of ad2s1210_set_mode() while we are touching this.
>
> Signed-off-by: David Lechner <dlechner@baylibre.com>
Applied,

Thanks,
Jonathan

> ---
>
> v3 changes:
> * Fixed multiline comment style.
>
> drivers/staging/iio/resolver/ad2s1210.c | 164 +++++++++++++++++---------------
> 1 file changed, 85 insertions(+), 79 deletions(-)
>
> diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
> index 2b9377447f6a..0ec3598b600a 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.c
> +++ b/drivers/staging/iio/resolver/ad2s1210.c
> @@ -58,39 +58,21 @@
> #define AD2S1210_DEF_EXCIT 10000
>
> enum ad2s1210_mode {
> - MOD_POS = 0,
> - MOD_VEL,
> - MOD_CONFIG,
> - MOD_RESERVED,
> + MOD_POS = 0b00,
> + MOD_VEL = 0b01,
> + MOD_RESERVED = 0b10,
> + MOD_CONFIG = 0b11,
> };
>
> -enum ad2s1210_gpios {
> - AD2S1210_SAMPLE,
> - AD2S1210_A0,
> - AD2S1210_A1,
> - AD2S1210_RES0,
> - AD2S1210_RES1,
> -};
> -
> -struct ad2s1210_gpio {
> - const char *name;
> - unsigned long flags;
> -};
> -
> -static const struct ad2s1210_gpio gpios[] = {
> - [AD2S1210_SAMPLE] = { .name = "adi,sample", .flags = GPIOD_OUT_LOW },
> - [AD2S1210_A0] = { .name = "adi,a0", .flags = GPIOD_OUT_LOW },
> - [AD2S1210_A1] = { .name = "adi,a1", .flags = GPIOD_OUT_LOW },
> - [AD2S1210_RES0] = { .name = "adi,res0", .flags = GPIOD_OUT_LOW },
> - [AD2S1210_RES1] = { .name = "adi,res1", .flags = GPIOD_OUT_LOW },
> -};
> -
> -static const unsigned int ad2s1210_resolution_value[] = { 10, 12, 14, 16 };
> -
> struct ad2s1210_state {
> struct mutex lock;
> struct spi_device *sdev;
> - struct gpio_desc *gpios[5];
> + /** GPIO pin connected to SAMPLE line. */
> + struct gpio_desc *sample_gpio;
> + /** GPIO pins connected to A0 and A1 lines. */
> + struct gpio_descs *mode_gpios;
> + /** GPIO pins connected to RES0 and RES1 lines. */
> + struct gpio_descs *resolution_gpios;
> /** Used to access config registers. */
> struct regmap *regmap;
> /** The external oscillator frequency in Hz. */
> @@ -98,7 +80,6 @@ struct ad2s1210_state {
> unsigned int fexcit;
> bool hysteresis;
> u8 resolution;
> - enum ad2s1210_mode mode;
> /** For reading raw sample value via SPI. */
> __be16 sample __aligned(IIO_DMA_MINALIGN);
> /** SPI transmit buffer. */
> @@ -107,18 +88,15 @@ struct ad2s1210_state {
> u8 tx[2];
> };
>
> -static const int ad2s1210_mode_vals[4][2] = {
> - [MOD_POS] = { 0, 0 },
> - [MOD_VEL] = { 0, 1 },
> - [MOD_CONFIG] = { 1, 1 },
> -};
> -
> -static inline void ad2s1210_set_mode(enum ad2s1210_mode mode,
> - struct ad2s1210_state *st)
> +static int ad2s1210_set_mode(struct ad2s1210_state *st, enum ad2s1210_mode mode)
> {
> - gpiod_set_value(st->gpios[AD2S1210_A0], ad2s1210_mode_vals[mode][0]);
> - gpiod_set_value(st->gpios[AD2S1210_A1], ad2s1210_mode_vals[mode][1]);
> - st->mode = mode;
> + struct gpio_descs *gpios = st->mode_gpios;
> + DECLARE_BITMAP(bitmap, 2);
> +
> + bitmap[0] = mode;
> +
> + return gpiod_set_array_value(gpios->ndescs, gpios->desc, gpios->info,
> + bitmap);
> }
>
> /*
> @@ -143,6 +121,7 @@ static int ad2s1210_regmap_reg_write(void *context, unsigned int reg,
> .tx_buf = &st->tx[1],
> },
> };
> + int ret;
>
> /* values can only be 7 bits, the MSB indicates an address */
> if (val & ~0x7F)
> @@ -151,7 +130,9 @@ static int ad2s1210_regmap_reg_write(void *context, unsigned int reg,
> st->tx[0] = reg;
> st->tx[1] = val;
>
> - ad2s1210_set_mode(MOD_CONFIG, st);
> + ret = ad2s1210_set_mode(st, MOD_CONFIG);
> + if (ret < 0)
> + return ret;
>
> return spi_sync_transfer(st->sdev, xfers, ARRAY_SIZE(xfers));
> }
> @@ -180,7 +161,10 @@ static int ad2s1210_regmap_reg_read(void *context, unsigned int reg,
> };
> int ret;
>
> - ad2s1210_set_mode(MOD_CONFIG, st);
> + ret = ad2s1210_set_mode(st, MOD_CONFIG);
> + if (ret < 0)
> + return ret;
> +
> st->tx[0] = reg;
> /*
> * Must be valid register address here otherwise this could write data.
> @@ -219,16 +203,16 @@ int ad2s1210_update_frequency_control_word(struct ad2s1210_state *st)
> return regmap_write(st->regmap, AD2S1210_REG_EXCIT_FREQ, fcw);
> }
>
> -static const int ad2s1210_res_pins[4][2] = {
> - { 0, 0 }, {0, 1}, {1, 0}, {1, 1}
> -};
> -
> -static inline void ad2s1210_set_resolution_pin(struct ad2s1210_state *st)
> +static int ad2s1210_set_resolution_gpios(struct ad2s1210_state *st,
> + u8 resolution)
> {
> - gpiod_set_value(st->gpios[AD2S1210_RES0],
> - ad2s1210_res_pins[(st->resolution - 10) / 2][0]);
> - gpiod_set_value(st->gpios[AD2S1210_RES1],
> - ad2s1210_res_pins[(st->resolution - 10) / 2][1]);
> + struct gpio_descs *gpios = st->resolution_gpios;
> + DECLARE_BITMAP(bitmap, 2);
> +
> + bitmap[0] = (resolution - 10) >> 1;
> +
> + return gpiod_set_array_value(gpios->ndescs, gpios->desc, gpios->info,
> + bitmap);
> }
>
> static inline int ad2s1210_soft_reset(struct ad2s1210_state *st)
> @@ -305,10 +289,13 @@ static ssize_t ad2s1210_store_resolution(struct device *dev,
> if (ret < 0)
> goto error_ret;
>
> - st->resolution =
> - ad2s1210_resolution_value[data & AD2S1210_SET_RES];
> - ad2s1210_set_resolution_pin(st);
> + ret = ad2s1210_set_resolution_gpios(st, udata);
> + if (ret < 0)
> + goto error_ret;
> +
> + st->resolution = udata;
> ret = len;
> +
> error_ret:
> mutex_unlock(&st->lock);
> return ret;
> @@ -339,15 +326,19 @@ static ssize_t ad2s1210_clear_fault(struct device *dev,
> int ret;
>
> mutex_lock(&st->lock);
> - gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
> +
> + gpiod_set_value(st->sample_gpio, 1);
> /* delay (2 * tck + 20) nano seconds */
> udelay(1);
> - gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
> + gpiod_set_value(st->sample_gpio, 0);
> +
> ret = regmap_read(st->regmap, AD2S1210_REG_FAULT, &value);
> if (ret < 0)
> goto error_ret;
> - gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
> - gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
> +
> + gpiod_set_value(st->sample_gpio, 1);
> + gpiod_set_value(st->sample_gpio, 0);
> +
> error_ret:
> mutex_unlock(&st->lock);
>
> @@ -393,19 +384,19 @@ static int ad2s1210_single_conversion(struct ad2s1210_state *st,
> struct iio_chan_spec const *chan,
> int *val)
> {
> - int ret = 0;
> + int ret;
>
> mutex_lock(&st->lock);
> - gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
> + gpiod_set_value(st->sample_gpio, 1);
> /* delay (6 * tck + 20) nano seconds */
> udelay(1);
>
> switch (chan->type) {
> case IIO_ANGL:
> - ad2s1210_set_mode(MOD_POS, st);
> + ret = ad2s1210_set_mode(st, MOD_POS);
> break;
> case IIO_ANGL_VEL:
> - ad2s1210_set_mode(MOD_VEL, st);
> + ret = ad2s1210_set_mode(st, MOD_VEL);
> break;
> default:
> ret = -EINVAL;
> @@ -432,7 +423,7 @@ static int ad2s1210_single_conversion(struct ad2s1210_state *st,
> }
>
> error_ret:
> - gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
> + gpiod_set_value(st->sample_gpio, 0);
> /* delay (2 * tck + 20) nano seconds */
> udelay(1);
> mutex_unlock(&st->lock);
> @@ -546,7 +537,9 @@ static int ad2s1210_initial(struct ad2s1210_state *st)
> int ret;
>
> mutex_lock(&st->lock);
> - ad2s1210_set_resolution_pin(st);
> + ret = ad2s1210_set_resolution_gpios(st, st->resolution);
> + if (ret < 0)
> + return ret;
>
> /* Use default config register value plus resolution from devicetree. */
> data = FIELD_PREP(AD2S1210_PHASE_LOCK_RANGE_44, 1);
> @@ -612,20 +605,34 @@ static int ad2s1210_setup_clocks(struct ad2s1210_state *st)
>
> static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
> {
> - struct spi_device *spi = st->sdev;
> - int i, ret;
> -
> - for (i = 0; i < ARRAY_SIZE(gpios); i++) {
> - st->gpios[i] = devm_gpiod_get(&spi->dev, gpios[i].name,
> - gpios[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",
> - gpios[i].name, ret);
> - return ret;
> - }
> - }
> + struct device *dev = &st->sdev->dev;
> +
> + /* should not be sampling on startup */
> + st->sample_gpio = devm_gpiod_get(dev, "sample", GPIOD_OUT_LOW);
> + if (IS_ERR(st->sample_gpio))
> + return dev_err_probe(dev, PTR_ERR(st->sample_gpio),
> + "failed to request sample GPIO\n");
> +
> + /* both pins high means that we start in config mode */
> + st->mode_gpios = devm_gpiod_get_array(dev, "mode", GPIOD_OUT_HIGH);
> + if (IS_ERR(st->mode_gpios))
> + return dev_err_probe(dev, PTR_ERR(st->mode_gpios),
> + "failed to request mode GPIOs\n");
> +
> + if (st->mode_gpios->ndescs != 2)
> + return dev_err_probe(dev, -EINVAL,
> + "requires exactly 2 mode-gpios\n");
> +
> + /* both pins high means that we start with 16-bit resolution */
> + st->resolution_gpios = devm_gpiod_get_array(dev, "resolution",
> + GPIOD_OUT_HIGH);
> + if (IS_ERR(st->resolution_gpios))
> + return dev_err_probe(dev, PTR_ERR(st->resolution_gpios),
> + "failed to request resolution GPIOs\n");
> +
> + if (st->resolution_gpios->ndescs != 2)
> + return dev_err_probe(dev, -EINVAL,
> + "requires exactly 2 resolution-gpios\n");
>
> return 0;
> }
> @@ -690,7 +697,6 @@ static int ad2s1210_probe(struct spi_device *spi)
> mutex_init(&st->lock);
> st->sdev = spi;
> st->hysteresis = true;
> - st->mode = MOD_CONFIG;
> st->resolution = 12;
> st->fexcit = AD2S1210_DEF_EXCIT;
>
>