[PATCH v4 17/17] staging: iio: resolver: ad2s1210: simplify code with guard(mutex)

From: David Lechner
Date: Thu Oct 05 2023 - 20:52:26 EST

We can simplify the code and get rid of most of the gotos by using
guard(mutex) from cleanup.h.

Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
---

v4 changes: New patch in v4.

drivers/staging/iio/resolver/ad2s1210.c | 157 ++++++++++----------------------
1 file changed, 50 insertions(+), 107 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index c4e1bc22e8b0..c4e0ffa92dc2 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -47,6 +47,7 @@

#include <linux/bitfield.h>
#include <linux/bits.h>
+#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
@@ -404,11 +405,13 @@ static int ad2s1210_single_conversion(struct iio_dev *indio_dev,
s64 timestamp;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
+
gpiod_set_value(st->sample_gpio, 1);
timestamp = iio_get_time_ns(indio_dev);
/* delay (6 * tck + 20) nano seconds */
udelay(1);
+ gpiod_set_value(st->sample_gpio, 0);

switch (chan->type) {
case IIO_ANGL:
@@ -418,14 +421,13 @@ static int ad2s1210_single_conversion(struct iio_dev *indio_dev,
ret = ad2s1210_set_mode(st, MOD_VEL);
break;
default:
- ret = -EINVAL;
- break;
+ return -EINVAL;
}
if (ret < 0)
- goto error_ret;
+ return ret;
ret = spi_read(st->sdev, &st->sample, 3);
if (ret < 0)
- goto error_ret;
+ return ret;

switch (chan->type) {
case IIO_ANGL:
@@ -437,17 +439,11 @@ static int ad2s1210_single_conversion(struct iio_dev *indio_dev,
ret = IIO_VAL_INT;
break;
default:
- ret = -EINVAL;
- break;
+ return -EINVAL;
}

ad2s1210_push_events(indio_dev, st->sample.fault, timestamp);

-error_ret:
- gpiod_set_value(st->sample_gpio, 0);
- /* delay (2 * tck + 20) nano seconds */
- udelay(1);
- mutex_unlock(&st->lock);
return ret;
}

@@ -455,11 +451,9 @@ static int ad2s1210_get_hysteresis(struct ad2s1210_state *st, int *val)
{
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
ret = regmap_test_bits(st->regmap, AD2S1210_REG_CONTROL,
AD2S1210_ENABLE_HYSTERESIS);
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -469,15 +463,10 @@ static int ad2s1210_get_hysteresis(struct ad2s1210_state *st, int *val)

static int ad2s1210_set_hysteresis(struct ad2s1210_state *st, int val)
{
- int ret;
-
- mutex_lock(&st->lock);
- ret = regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL,
- AD2S1210_ENABLE_HYSTERESIS,
- val ? AD2S1210_ENABLE_HYSTERESIS : 0);
- mutex_unlock(&st->lock);
-
- return ret;
+ guard(mutex)(&st->lock);
+ return regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL,
+ AD2S1210_ENABLE_HYSTERESIS,
+ val ? AD2S1210_ENABLE_HYSTERESIS : 0);
}

static int ad2s1210_get_phase_lock_range(struct ad2s1210_state *st,
@@ -485,11 +474,9 @@ static int ad2s1210_get_phase_lock_range(struct ad2s1210_state *st,
{
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
ret = regmap_test_bits(st->regmap, AD2S1210_REG_CONTROL,
AD2S1210_PHASE_LOCK_RANGE_44);
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -509,7 +496,7 @@ static int ad2s1210_get_phase_lock_range(struct ad2s1210_state *st,
static int ad2s1210_set_phase_lock_range(struct ad2s1210_state *st,
int val, int val2)
{
- int deg, ret;
+ int deg;

/* convert radians to degrees - only two allowable values */
if (val == PHASE_44_DEG_TO_RAD_INT && val2 == PHASE_44_DEG_TO_RAD_MICRO)
@@ -520,12 +507,10 @@ static int ad2s1210_set_phase_lock_range(struct ad2s1210_state *st,
else
return -EINVAL;

- mutex_lock(&st->lock);
- ret = regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL,
- AD2S1210_PHASE_LOCK_RANGE_44,
- deg == 44 ? AD2S1210_PHASE_LOCK_RANGE_44 : 0);
- mutex_unlock(&st->lock);
- return ret;
+ guard(mutex)(&st->lock);
+ return regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL,
+ AD2S1210_PHASE_LOCK_RANGE_44,
+ deg == 44 ? AD2S1210_PHASE_LOCK_RANGE_44 : 0);
}

/* map resolution to microradians/LSB for LOT registers */
@@ -542,10 +527,8 @@ static int ad2s1210_get_voltage_threshold(struct ad2s1210_state *st,
unsigned int reg_val;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
ret = regmap_read(st->regmap, reg, &reg_val);
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -557,15 +540,11 @@ static int ad2s1210_set_voltage_threshold(struct ad2s1210_state *st,
unsigned int reg, int val)
{
unsigned int reg_val;
- int ret;

reg_val = val / THRESHOLD_MILLIVOLT_PER_LSB;

- mutex_lock(&st->lock);
- ret = regmap_write(st->regmap, reg, reg_val);
- mutex_unlock(&st->lock);
-
- return ret;
+ guard(mutex)(&st->lock);
+ return regmap_write(st->regmap, reg, reg_val);
}

static int ad2s1210_get_lot_high_threshold(struct ad2s1210_state *st,
@@ -574,10 +553,8 @@ static int ad2s1210_get_lot_high_threshold(struct ad2s1210_state *st,
unsigned int reg_val;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
ret = regmap_read(st->regmap, AD2S1210_REG_LOT_HIGH_THRD, &reg_val);
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -596,18 +573,18 @@ static int ad2s1210_set_lot_high_threshold(struct ad2s1210_state *st,
if (val != 0)
return -EINVAL;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
/*
* We need to read both high and low registers first so we can preserve
* the hysteresis.
*/
ret = regmap_read(st->regmap, AD2S1210_REG_LOT_HIGH_THRD, &high_reg_val);
if (ret < 0)
- goto error_ret;
+ return ret;

ret = regmap_read(st->regmap, AD2S1210_REG_LOT_LOW_THRD, &low_reg_val);
if (ret < 0)
- goto error_ret;
+ return ret;

hysteresis = high_reg_val - low_reg_val;
high_reg_val = val2 / ad2s1210_lot_threshold_urad_per_lsb[st->resolution];
@@ -615,14 +592,9 @@ static int ad2s1210_set_lot_high_threshold(struct ad2s1210_state *st,

ret = regmap_write(st->regmap, AD2S1210_REG_LOT_HIGH_THRD, high_reg_val);
if (ret < 0)
- goto error_ret;
-
- ret = regmap_write(st->regmap, AD2S1210_REG_LOT_LOW_THRD, low_reg_val);
-
-error_ret:
- mutex_unlock(&st->lock);
+ return ret;

- return ret;
+ return regmap_write(st->regmap, AD2S1210_REG_LOT_LOW_THRD, low_reg_val);
}

static int ad2s1210_get_lot_low_threshold(struct ad2s1210_state *st,
@@ -631,16 +603,13 @@ static int ad2s1210_get_lot_low_threshold(struct ad2s1210_state *st,
unsigned int high_reg_val, low_reg_val;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
+
ret = regmap_read(st->regmap, AD2S1210_REG_LOT_HIGH_THRD, &high_reg_val);
if (ret < 0)
- goto error_ret;
+ return ret;

ret = regmap_read(st->regmap, AD2S1210_REG_LOT_LOW_THRD, &low_reg_val);
-
-error_ret:
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -663,18 +632,14 @@ static int ad2s1210_set_lot_low_threshold(struct ad2s1210_state *st,

hysteresis = val2 / ad2s1210_lot_threshold_urad_per_lsb[st->resolution];

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
+
ret = regmap_read(st->regmap, AD2S1210_REG_LOT_HIGH_THRD, &reg_val);
if (ret < 0)
- goto error_ret;
+ return ret;

- ret = regmap_write(st->regmap, AD2S1210_REG_LOT_LOW_THRD,
+ return regmap_write(st->regmap, AD2S1210_REG_LOT_LOW_THRD,
reg_val - hysteresis);
-
-error_ret:
- mutex_unlock(&st->lock);
-
- return ret;
}

static int ad2s1210_get_excitation_frequency(struct ad2s1210_state *st, int *val)
@@ -682,31 +647,23 @@ static int ad2s1210_get_excitation_frequency(struct ad2s1210_state *st, int *val
unsigned int reg_val;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
+
ret = regmap_read(st->regmap, AD2S1210_REG_EXCIT_FREQ, &reg_val);
if (ret < 0)
- goto error_ret;
+ return ret;

*val = reg_val * st->clkin_hz / (1 << 15);
- ret = IIO_VAL_INT;
-
-error_ret:
- mutex_unlock(&st->lock);
- return ret;
+ return IIO_VAL_INT;
}

static int ad2s1210_set_excitation_frequency(struct ad2s1210_state *st, int val)
{
- int ret;
-
if (val < AD2S1210_MIN_EXCIT || val > AD2S1210_MAX_EXCIT)
return -EINVAL;

- mutex_lock(&st->lock);
- ret = ad2s1210_reinit_excitation_frequency(st, val);
- mutex_unlock(&st->lock);
-
- return ret;
+ guard(mutex)(&st->lock);
+ return ad2s1210_reinit_excitation_frequency(st, val);
}

static const int ad2s1210_velocity_scale[] = {
@@ -982,10 +939,8 @@ static ssize_t event_attr_voltage_reg_show(struct device *dev,
unsigned int value;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
ret = regmap_read(st->regmap, iattr->address, &value);
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -1005,11 +960,9 @@ static ssize_t event_attr_voltage_reg_store(struct device *dev,
if (ret)
return -EINVAL;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
ret = regmap_write(st->regmap, iattr->address,
data / THRESHOLD_MILLIVOLT_PER_LSB);
- mutex_unlock(&st->lock);
-
if (ret < 0)
return ret;

@@ -1083,7 +1036,7 @@ static int ad2s1210_initial(struct ad2s1210_state *st)
unsigned int data;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);

/* Use default config register value plus resolution from devicetree. */
data = FIELD_PREP(AD2S1210_PHASE_LOCK_RANGE_44, 1);
@@ -1093,13 +1046,9 @@ static int ad2s1210_initial(struct ad2s1210_state *st)

ret = regmap_write(st->regmap, AD2S1210_REG_CONTROL, data);
if (ret < 0)
- goto error_ret;
-
- ret = ad2s1210_reinit_excitation_frequency(st, AD2S1210_DEF_EXCIT);
+ return ret;

-error_ret:
- mutex_unlock(&st->lock);
- return ret;
+ return ad2s1210_reinit_excitation_frequency(st, AD2S1210_DEF_EXCIT);
}

static int ad2s1210_read_label(struct iio_dev *indio_dev,
@@ -1243,18 +1192,13 @@ static int ad2s1210_debugfs_reg_access(struct iio_dev *indio_dev,
unsigned int *readval)
{
struct ad2s1210_state *st = iio_priv(indio_dev);
- int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);

if (readval)
- ret = regmap_read(st->regmap, reg, readval);
- else
- ret = regmap_write(st->regmap, reg, writeval);
-
- mutex_unlock(&st->lock);
+ return regmap_read(st->regmap, reg, readval);

- return ret;
+ return regmap_write(st->regmap, reg, writeval);
}

static irqreturn_t ad2s1210_trigger_handler(int irq, void *p)
@@ -1265,7 +1209,7 @@ static irqreturn_t ad2s1210_trigger_handler(int irq, void *p)
size_t chan = 0;
int ret;

- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);

memset(&st->scan, 0, sizeof(st->scan));
gpiod_set_value(st->sample_gpio, 1);
@@ -1299,7 +1243,6 @@ static irqreturn_t ad2s1210_trigger_handler(int irq, void *p)

error_ret:
gpiod_set_value(st->sample_gpio, 0);
- mutex_unlock(&st->lock);
iio_trigger_notify_done(indio_dev->trig);

return IRQ_HANDLED;

--
2.42.0