On 9/17/20 3:18 AM, Alban Bedel wrote:
> Add regulator support for boards where the sensor first need to be
> powered up before it can be used.
>
> Signed-off-by: Alban Bedel <[email protected]>
> ---
> drivers/hwmon/lm75.c | 31 +++++++++++++++++++++++++++++--
> 1 file changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> index ba0be48aeadd..b673f8d2ef20 100644
> --- a/drivers/hwmon/lm75.c
> +++ b/drivers/hwmon/lm75.c
> @@ -17,6 +17,7 @@
> #include <linux/of.h>
> #include <linux/regmap.h>
> #include <linux/util_macros.h>
> +#include <linux/regulator/consumer.h>
> #include "lm75.h"
>
> /*
> @@ -101,6 +102,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49,
> 0x4a, 0x4b, 0x4c,
> struct lm75_data {
> struct i2c_client *client;
> struct regmap *regmap;
> + struct regulator *vs;
> u8 orig_conf;
> u8 current_conf;
> u8 resolution; /* In bits, 9 to 16 */
> @@ -540,6 +542,8 @@ static void lm75_remove(void *data)
> struct i2c_client *client = lm75->client;
>
> i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
> + if (lm75->vs)
> + regulator_disable(lm75->vs);
> }
>
> static int
> @@ -567,6 +571,14 @@ lm75_probe(struct i2c_client *client, const struct
> i2c_device_id *id)
> data->client = client;
> data->kind = kind;
>
> + data->vs = devm_regulator_get_optional(dev, "vs");
Looking into the regulator API, it may be better if you use
devm_regulator_get().
AFAICS it returns a dummy regulator if there is none, and NULL if the regulator
subsystem is disabled. So
data->vs = devm_regulator_get(dev, "vs");
if (IS_ERR(data->vs))
return PTR_ERR(data->vs);
should work and would be less messy.
> + if (IS_ERR(data->vs)) {
> + if (PTR_ERR(data->vs) == -ENODEV)
> + data->vs = NULL;
> + else
> + return PTR_ERR(data->vs);
> + }
> +
> data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
> if (IS_ERR(data->regmap))
> return PTR_ERR(data->regmap);
> @@ -581,11 +593,21 @@ lm75_probe(struct i2c_client *client, const struct
> i2c_device_id *id)
> data->sample_time = data->params->default_sample_time;
> data->resolution = data->params->default_resolution;
>
> + /* Enable the power */
> + if (data->vs) {
> + err = regulator_enable(data->vs);
> + if (err) {
> + dev_err(dev, "failed to enable regulator: %d\n", err);
> + return err;
> + }
> + }
> +
How about device removal ? Don't you have to call regulator_disable()
there as well ? If so, it might be best to use devm_add_action_or_reset()
to register a disable function.
Thanks,
Guenter
> /* Cache original configuration */
> status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
> if (status < 0) {
> dev_dbg(dev, "Can't read config? %d\n", status);
> - return status;
> + err = status;
> + goto disable_regulator;
> }
> data->orig_conf = status;
> data->current_conf = status;
> @@ -593,7 +615,7 @@ lm75_probe(struct i2c_client *client, const struct
> i2c_device_id *id)
> err = lm75_write_config(data, data->params->set_mask,
> data->params->clr_mask);
> if (err)
> - return err;
> + goto disable_regulator;
>
> err = devm_add_action_or_reset(dev, lm75_remove, data);
> if (err)
> @@ -608,6 +630,11 @@ lm75_probe(struct i2c_client *client, const struct
> i2c_device_id *id)
> dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
>
> return 0;
> +
> +disable_regulator:
> + if (data->vs)
> + regulator_disable(data->vs);
> + return err;
> }
>
> static const struct i2c_device_id lm75_ids[] = {
>
