staging: iio: resolver: ad2s1210: rework gpios

- 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>
Link: https://lore.kernel.org/r/20230929-ad2s1210-mainline-v3-13-fa4364281745@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 2b9377447f6a9a36a3140df6cbe63aa1c08de58c..5744f1673cbaf56b7046af71e3c930ef38249aaa 100644 (file)
--- 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)
+               goto error_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;