diff mbox series

[v2,04/14] hwmon: (ina2xx) Mark regmap_config as const

Message ID 20240830010554.1462861-5-linux@roeck-us.net (mailing list archive)
State Accepted
Headers show
Series hwmon: (ina2xx) Cleanup and convert to use with_info API | expand

Commit Message

Guenter Roeck Aug. 30, 2024, 1:05 a.m. UTC 
Recent versions of checkpatch complain that struct regmap_config
should be declared as const.

WARNING: struct regmap_config should normally be const

Doing so reveals a potential problem in the driver: If both supported
chips are present in a single system, the maximum number of registers
may race when devices are instantiated since max_registers is updated
in the probe function. Solve the problem by setting .max_registers to the
maximum register address of all supported chips. This does not make a
practical difference while fixing the potential race condition and reducing
code complexity.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Fixed typo in patch description (devic es -> devices)

 drivers/hwmon/ina2xx.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

Comments

Tzung-Bi Shih Aug. 30, 2024, 12:28 p.m. UTC | #1 
On Thu, Aug 29, 2024 at 06:05:44PM -0700, Guenter Roeck wrote:
> Recent versions of checkpatch complain that struct regmap_config
> should be declared as const.
> 
> WARNING: struct regmap_config should normally be const
> 
> Doing so reveals a potential problem in the driver: If both supported
> chips are present in a single system, the maximum number of registers
> may race when devices are instantiated since max_registers is updated
> in the probe function. Solve the problem by setting .max_registers to the
> maximum register address of all supported chips. This does not make a
> practical difference while fixing the potential race condition and reducing
> code complexity.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
diff mbox series

Patch

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index 1b4170d02c94..9d93190874d7 100644
--- a/drivers/hwmon/ina2xx.c
+++ b/drivers/hwmon/ina2xx.c
@@ -50,10 +50,6 @@ 
 #define INA226_ALERT_LIMIT		0x07
 #define INA226_DIE_ID			0xFF
 
-/* register count */
-#define INA219_REGISTERS		6
-#define INA226_REGISTERS		8
-
 #define INA2XX_MAX_REGISTERS		8
 
 /* settings - depend on use case */
@@ -95,9 +91,10 @@ 
  */
 #define INA226_TOTAL_CONV_TIME_DEFAULT	2200
 
-static struct regmap_config ina2xx_regmap_config = {
+static const struct regmap_config ina2xx_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 16,
+	.max_register = INA2XX_MAX_REGISTERS,
 };
 
 enum ina2xx_ids { ina219, ina226 };
@@ -105,7 +102,6 @@  enum ina2xx_ids { ina219, ina226 };
 struct ina2xx_config {
 	u16 config_default;
 	int calibration_value;
-	int registers;
 	int shunt_div;
 	int bus_voltage_shift;
 	int bus_voltage_lsb;	/* uV */
@@ -128,7 +124,6 @@  static const struct ina2xx_config ina2xx_config[] = {
 	[ina219] = {
 		.config_default = INA219_CONFIG_DEFAULT,
 		.calibration_value = 4096,
-		.registers = INA219_REGISTERS,
 		.shunt_div = 100,
 		.bus_voltage_shift = 3,
 		.bus_voltage_lsb = 4000,
@@ -137,7 +132,6 @@  static const struct ina2xx_config ina2xx_config[] = {
 	[ina226] = {
 		.config_default = INA226_CONFIG_DEFAULT,
 		.calibration_value = 2048,
-		.registers = INA226_REGISTERS,
 		.shunt_div = 400,
 		.bus_voltage_shift = 0,
 		.bus_voltage_lsb = 1250,
@@ -646,8 +640,6 @@  static int ina2xx_probe(struct i2c_client *client)
 
 	ina2xx_set_shunt(data, val);
 
-	ina2xx_regmap_config.max_register = data->config->registers;
-
 	data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
 	if (IS_ERR(data->regmap)) {
 		dev_err(dev, "failed to allocate register map\n");