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]>
---
v2: Rely on dummy regulators instead of explicitly handling missing
regulator
---
drivers/hwmon/lm75.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index ba0be48aeadd..e394df648c26 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 +542,7 @@ static void lm75_remove(void *data)
struct i2c_client *client = lm75->client;
i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
+ regulator_disable(lm75->vs);
}
static int
@@ -567,6 +570,10 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
data->client = client;
data->kind = kind;
+ data->vs = devm_regulator_get(dev, "vs");
+ if (IS_ERR(data->vs))
+ 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 +588,19 @@ 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 */
+ err = regulator_enable(data->vs);
+ if (err) {
+ dev_err(dev, "failed to enable regulator: %d\n", err);
+ return err;
+ }
+
/* 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 +608,7 @@ 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 +623,10 @@ 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:
+ regulator_disable(data->vs);
+ return err;
}
static const struct i2c_device_id lm75_ids[] = {
--
2.25.1
On Mon, Sep 28, 2020 at 05:39:23PM +0200, 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]>
> ---
> v2: Rely on dummy regulators instead of explicitly handling missing
> regulator
> ---
> drivers/hwmon/lm75.c | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> index ba0be48aeadd..e394df648c26 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 +542,7 @@ static void lm75_remove(void *data)
> struct i2c_client *client = lm75->client;
>
> i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
> + regulator_disable(lm75->vs);
> }
>
> static int
> @@ -567,6 +570,10 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
> data->client = client;
> data->kind = kind;
>
> + data->vs = devm_regulator_get(dev, "vs");
> + if (IS_ERR(data->vs))
> + 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 +588,19 @@ 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 */
> + err = regulator_enable(data->vs);
> + if (err) {
> + dev_err(dev, "failed to enable regulator: %d\n", err);
> + return err;
> + }
> +
> /* 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;
The point of using devm_add_action_or_reset() was specifically to avoid having
to have the cleanup gotos. On top of that, the lm75_remove() function was
specifically intended to clean up configuration data, not to do anything else.
While hijacking lm75_remove() to also disable the regulator is technically
correct, it makes the code more difficult to understand, and it creates a
potential source for subsequently introduced bugs. Right now I am not inclined
to accept this code as-is. Please provide arguments for handling the cleanup
this way instead of using devm_add_action_or_reset().
Thanks,
Guenter
On Mon, 2020-09-28 at 09:39 -0700, Guenter Roeck wrote:
> On Mon, Sep 28, 2020 at 05:39:23PM +0200, 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]>
> > ---
> > v2: Rely on dummy regulators instead of explicitly handling missing
> > regulator
> > ---
> > drivers/hwmon/lm75.c | 23 +++++++++++++++++++++--
> > 1 file changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> > index ba0be48aeadd..e394df648c26 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 +542,7 @@ static void lm75_remove(void *data)
> > struct i2c_client *client = lm75->client;
> >
> > i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75-
> > >orig_conf);
> > + regulator_disable(lm75->vs);
> > }
> >
> > static int
> > @@ -567,6 +570,10 @@ lm75_probe(struct i2c_client *client, const
> > struct i2c_device_id *id)
> > data->client = client;
> > data->kind = kind;
> >
> > + data->vs = devm_regulator_get(dev, "vs");
> > + if (IS_ERR(data->vs))
> > + 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 +588,19 @@ 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 */
> > + err = regulator_enable(data->vs);
> > + if (err) {
> > + dev_err(dev, "failed to enable regulator: %d\n", err);
> > + return err;
> > + }
> > +
> > /* 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;
>
> The point of using devm_add_action_or_reset() was specifically to avoid having
> to have the cleanup gotos. On top of that, the lm75_remove() function was
> specifically intended to clean up configuration data, not to do anything else.
> While hijacking lm75_remove() to also disable the regulator is technically
> correct, it makes the code more difficult to understand, and it creates a
> potential source for subsequently introduced bugs. Right now I am not inclined
> to accept this code as-is. Please provide arguments for handling the cleanup
> this way instead of using devm_add_action_or_reset().
I wrote it that way to keep the memory usage lower, but I see your
point and will update the patch accordingly.
Alban