[PATCH v8 2/5] iio: dac: mcp47feb02: protect EEPROM store sequence with mutex

[Ariana Lazar <ariana.lazar@microchip.com>]

Move the mutex lock into store_eeprom_store() to prevent race conditions
when reading volatile registers and writing them to the EEPROM.

Fixes: bf394cc80369 ("iio: dac: adding support for Microchip MCP47FEB02")
Closes: https://lore.kernel.org/all/20260819125128.970911F000E9@smtp.kernel.org/
Signed-off-by: Ariana Lazar <ariana.lazar@microchip.com>
---
 drivers/iio/dac/mcp47feb02.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/dac/mcp47feb02.c b/drivers/iio/dac/mcp47feb02.c
index 349574bc7489d9e5ac9722c3abbaaab0d2c3350e..8f8a67919cc2ecdb203ad350174bac2be1a307dc 100644
--- a/drivers/iio/dac/mcp47feb02.c
+++ b/drivers/iio/dac/mcp47feb02.c
@@ -440,8 +440,6 @@ static int mcp47feb02_write_to_eeprom(struct mcp47feb02_data *data, unsigned int
 	 * Wait until the currently occurring EEPROM Write Cycle is completed.
 	 * Only serial commands to the volatile memory are allowed.
 	 */
-	guard(mutex)(&data->lock);
-
 	ret = regmap_read_poll_timeout(data->regmap, MCP47FEB02_GAIN_CTRL_STATUS_REG_ADDR,
 				       eewa_val,
 				       !(eewa_val & MCP47FEB02_GAIN_BIT_STATUS_EEWA_MASK),
@@ -467,6 +465,8 @@ static ssize_t store_eeprom_store(struct device *dev, struct device_attribute *a
 	if (!state)
 		return len;
 
+	guard(mutex)(&data->lock);
+
 	/*
 	 * Verify DAC Wiper and DAC Configuration are unlocked. If both are disabled,
 	 * writing to EEPROM is available.

-- 
2.43.0