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iio: magnetometer: rm3100: Modernize locking and refactor control flow

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Replace mutex_lock() and mutex_unlock() calls in rm3100-core.c with
the more modern guard(mutex)() family. This will help modernize the
driver and bring it up-to-date with modern available macros/functions.

While replacing mutex_lock() and mutex_unlock(), the critical sections
of rm3100_read_mag() and rm3100_get_samp_freq() have been extended to
include negligible operations for cleaner logic.

Add new helper-wrapper function rm3100_regmap_bulk_read_locked() to
help keep rm3100_trigger_handler() switch-cases clean while maintaining
mutex locking and avoiding re-entrancy risks from potential callbacks.

While at it, remove redundant gotos where applicable, and use direct
returns instead. In addition, remove regmap variable in
rm3100_trigger_handler() as its references have been replaced with
variable data.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Maxwell Doose <m32285159@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Maxwell Doose 2026-04-30 07:41:47 -05:00 committed by Jonathan Cameron
parent d0b396cab2
commit 5a6249110e
1 changed files with 51 additions and 43 deletions
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94
drivers/iio/magnetometer/rm3100-core.c
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@ -204,27 +204,23 @@ static int rm3100_read_mag(struct rm3100_data *data, int idx, int *val)
u8 buffer[3];
int ret;
mutex_lock(&data->lock);
guard(mutex)(&data->lock);
ret = regmap_write(regmap, RM3100_REG_POLL, BIT(4 + idx));
if (ret < 0)
goto unlock_return;
return ret;
ret = rm3100_wait_measurement(data);
if (ret < 0)
goto unlock_return;
return ret;
ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * idx, buffer, 3);
if (ret < 0)
goto unlock_return;
mutex_unlock(&data->lock);
return ret;
*val = sign_extend32(get_unaligned_be24(&buffer[0]), 23);
return IIO_VAL_INT;
unlock_return:
mutex_unlock(&data->lock);
return ret;
}
#define RM3100_CHANNEL(axis, idx) \
@ -284,11 +280,12 @@ static int rm3100_get_samp_freq(struct rm3100_data *data, int *val, int *val2)
unsigned int tmp;
int ret;
mutex_lock(&data->lock);
guard(mutex)(&data->lock);
ret = regmap_read(data->regmap, RM3100_REG_TMRC, &tmp);
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
*val = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][0];
*val2 = rm3100_samp_rates[tmp - RM3100_TMRC_OFFSET][1];
@ -338,56 +335,50 @@ static int rm3100_set_samp_freq(struct iio_dev *indio_dev, int val, int val2)
int ret;
int i;
mutex_lock(&data->lock);
guard(mutex)(&data->lock);
/* All cycle count registers use the same value. */
ret = regmap_read(regmap, RM3100_REG_CC_X, &cycle_count);
if (ret < 0)
goto unlock_return;
return ret;
for (i = 0; i < RM3100_SAMP_NUM; i++) {
if (val == rm3100_samp_rates[i][0] &&
val2 == rm3100_samp_rates[i][1])
break;
}
if (i == RM3100_SAMP_NUM) {
ret = -EINVAL;
goto unlock_return;
}
if (i == RM3100_SAMP_NUM)
return -EINVAL;
ret = regmap_write(regmap, RM3100_REG_TMRC, i + RM3100_TMRC_OFFSET);
if (ret < 0)
goto unlock_return;
return ret;
/* Checking if cycle count registers need changing. */
if (val == 600 && cycle_count == 200) {
ret = rm3100_set_cycle_count(data, 100);
if (ret < 0)
goto unlock_return;
return ret;
} else if (val != 600 && cycle_count == 100) {
ret = rm3100_set_cycle_count(data, 200);
if (ret < 0)
goto unlock_return;
return ret;
}
if (iio_buffer_enabled(indio_dev)) {
/* Writing TMRC registers requires CMM reset. */
ret = regmap_write(regmap, RM3100_REG_CMM, 0);
if (ret < 0)
goto unlock_return;
return ret;
ret = regmap_write(data->regmap, RM3100_REG_CMM,
(*indio_dev->active_scan_mask & 0x7) <<
RM3100_CMM_AXIS_SHIFT | RM3100_CMM_START);
if (ret < 0)
goto unlock_return;
return ret;
}
mutex_unlock(&data->lock);
data->conversion_time = rm3100_samp_rates[i][2] * 2;
return 0;
unlock_return:
mutex_unlock(&data->lock);
return ret;
}
static int rm3100_read_raw(struct iio_dev *indio_dev,
@ -458,6 +449,27 @@ static const struct iio_buffer_setup_ops rm3100_buffer_ops = {
.postdisable = rm3100_buffer_postdisable,
};
/**
* rm3100_regmap_bulk_read_locked() - Wrapper around regmap_bulk_read() with a mutex
*
* @data: Data structure containing regmap and mutex
* @reg: First register to be read from, passed to regmap_bulk_read()
* @val: Pointer to store read value, in native register size for device,
* passed to regmap_bulk_read()
* @val_count: Number of registers to read, passed to regmap_bulk_read()
*
* Intended for use only in rm3100_trigger_handler().
*
* Return:
* A value of zero on success, a negative errno in error cases.
*/
static int rm3100_regmap_bulk_read_locked(struct rm3100_data *data, unsigned int reg,
void *val, size_t val_count)
{
guard(mutex)(&data->lock);
return regmap_bulk_read(data->regmap, reg, val, val_count);
}
static irqreturn_t rm3100_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
@ -465,14 +477,12 @@ static irqreturn_t rm3100_trigger_handler(int irq, void *p)
unsigned long scan_mask = *indio_dev->active_scan_mask;
unsigned int mask_len = iio_get_masklength(indio_dev);
struct rm3100_data *data = iio_priv(indio_dev);
struct regmap *regmap = data->regmap;
int ret, i, bit;
mutex_lock(&data->lock);
switch (scan_mask) {
case BIT(0) | BIT(1) | BIT(2):
ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
mutex_unlock(&data->lock);
ret = rm3100_regmap_bulk_read_locked(data, RM3100_REG_MX2,
data->buffer, 9);
if (ret < 0)
goto done;
/* Convert XXXYYYZZZxxx to XXXxYYYxZZZx. x for paddings. */
@ -480,36 +490,34 @@ static irqreturn_t rm3100_trigger_handler(int irq, void *p)
memmove(data->buffer + i * 4, data->buffer + i * 3, 3);
break;
case BIT(0) | BIT(1):
ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 6);
mutex_unlock(&data->lock);
ret = rm3100_regmap_bulk_read_locked(data, RM3100_REG_MX2,
data->buffer, 6);
if (ret < 0)
goto done;
memmove(data->buffer + 4, data->buffer + 3, 3);
break;
case BIT(1) | BIT(2):
ret = regmap_bulk_read(regmap, RM3100_REG_MY2, data->buffer, 6);
mutex_unlock(&data->lock);
ret = rm3100_regmap_bulk_read_locked(data, RM3100_REG_MY2,
data->buffer, 6);
if (ret < 0)
goto done;
memmove(data->buffer + 4, data->buffer + 3, 3);
break;
case BIT(0) | BIT(2):
ret = regmap_bulk_read(regmap, RM3100_REG_MX2, data->buffer, 9);
mutex_unlock(&data->lock);
ret = rm3100_regmap_bulk_read_locked(data, RM3100_REG_MX2,
data->buffer, 9);
if (ret < 0)
goto done;
memmove(data->buffer + 4, data->buffer + 6, 3);
break;
default:
for_each_set_bit(bit, &scan_mask, mask_len) {
ret = regmap_bulk_read(regmap, RM3100_REG_MX2 + 3 * bit,
data->buffer, 3);
if (ret < 0) {
mutex_unlock(&data->lock);
ret = rm3100_regmap_bulk_read_locked(data,
RM3100_REG_MX2 + 3 * bit,
data->buffer, 3);
if (ret < 0)
goto done;
}
}
mutex_unlock(&data->lock);
}
/*
* Always using the same buffer so that we wouldn't need to set the