[v2 12/19] staging: iio: resolver: ad2s1210: rework gpios

David Lechner
2023-09-21T17:53:58Z

- 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>
---
drivers/staging/iio/resolver/ad2s1210.c | 162 ++++++++++++------------
1 file changed, 84 insertions(+), 78 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 223cc4702188..7a1069d948eb 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -60,39 +60,21 @@
#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. */
@@ -100,23 +82,19 @@ struct ad2s1210_state {
unsigned int fexcit;
bool hysteresis;
u8 resolution;
- enum ad2s1210_mode mode;
u8 rx[2] __aligned(IIO_DMA_MINALIGN);
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);
}

/*
@@ -141,6 +119,7 @@ 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)
@@ -149,7 +128,9 @@ 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));
}
@@ -178,7 +159,10 @@ 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.
* It doesn't matter which one.
@@ -215,16 +199,16 @@ 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)
@@ -301,10 +285,13 @@ 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;
@@ -335,15 +322,19 @@ 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);

@@ -404,16 +395,16 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
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;
@@ -440,7 +431,7 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
}

error_info_raw:
- 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);
@@ -542,7 +533,9 @@ 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;

data = AD2S1210_DEF_CONTROL & ~AD2S1210_SET_RES;
data |= (st->resolution - 10) >> 1;
@@ -604,20 +597,34 @@ 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;
}
@@ -683,7 +690,6 @@ 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;

--
2.34.1