| Message ID | 20160724202620.GA30245@makrotopia.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 07/24/2016 01:26 PM, Daniel Golle wrote: > Allow to specify the resistance of the attached shunt via DT by > adding the shunt-resistor property. Fall-back to the previous > default (1 mOhm) if unset. > > Signed-off-by: Daniel Golle <daniel@makrotopia.org> > --- > drivers/hwmon/ltc4151.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/ltc4151.c b/drivers/hwmon/ltc4151.c > index c86a184..f856e44 100644 > --- a/drivers/hwmon/ltc4151.c > +++ b/drivers/hwmon/ltc4151.c > @@ -30,6 +30,8 @@ > > #include <linux/kernel.h> > #include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> I don't immediately see why this include file would be necessary. > #include <linux/init.h> > #include <linux/err.h> > #include <linux/slab.h> > @@ -52,6 +54,7 @@ struct ltc4151_data { > struct mutex update_lock; > bool valid; > unsigned long last_updated; /* in jiffies */ > + unsigned int shunt; /* in micro ohms */ > > /* Registers */ > u8 regs[6]; > @@ -111,9 +114,9 @@ static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) > case LTC4151_SENSE_H: > /* > * 20uV resolution. Convert to current as measured with > - * an 1 mOhm sense resistor, in mA. > + * a given sense resistor, in mA. > */ > - val = val * 20; > + val = val * 20 * 1000 / data->shunt; > break; > case LTC4151_VIN_H: > /* 25 mV per increment */ > @@ -176,6 +179,7 @@ static int ltc4151_probe(struct i2c_client *client, > struct device *dev = &client->dev; > struct ltc4151_data *data; > struct device *hwmon_dev; > + u32 shunt; > > if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) > return -ENODEV; > @@ -184,6 +188,14 @@ static int ltc4151_probe(struct i2c_client *client, > if (!data) > return -ENOMEM; > > +#ifdef CONFIG_OF #ifdef is unnecessary. Worse, it results in drivers/hwmon/ltc4151.c: In function ‘ltc4151_probe’: drivers/hwmon/ltc4151.c:182:6: warning: unused variable ‘shunt’ if CONFIG_OF is not defined. > + if (!of_property_read_u32(client->dev.of_node, "shunt-resistor", &shunt) > + && shunt > 0 ) checkpatch error > + data->shunt = shunt; shunt == 0 is silently accepted and replaced with 1000. This is quite unusual. Any reason ? If not, return -EINVAL might be more appropriate for shunt == 0. > + else > +#endif > + data->shunt = 1000; /* 1 mOhm if not set */ > + > data->client = client; > mutex_init(&data->update_lock); > > @@ -199,10 +211,20 @@ static const struct i2c_device_id ltc4151_id[] = { > }; > MODULE_DEVICE_TABLE(i2c, ltc4151_id); > > +#ifdef CONFIG_OF #ifdef is unnecessary. > +static const struct of_device_id ltc4151_match[] = { > + { .compatible = "lltc,ltc4151" }, This as well as the property need to be documented. > + {}, > +}; > +#endif > + > /* This is the driver that will be inserted */ > static struct i2c_driver ltc4151_driver = { > + .class = I2C_CLASS_HWMON, This is an unrelated change, and appears to be quite pointless, since the driver does not have a detect function. Any reason for adding it ? If so, please explain, and submit as separate patch. > .driver = { > .name = "ltc4151", > + .owner = THIS_MODULE, Is this now necessary again ? If so, please explain, and submit as separate patch. > + .of_match_table = of_match_ptr(ltc4151_match), > }, > .probe = ltc4151_probe, > .id_table = ltc4151_id, > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hwmon/ltc4151.c b/drivers/hwmon/ltc4151.c index c86a184..f856e44 100644 --- a/drivers/hwmon/ltc4151.c +++ b/drivers/hwmon/ltc4151.c @@ -30,6 +30,8 @@ #include <linux/kernel.h> #include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> #include <linux/init.h> #include <linux/err.h> #include <linux/slab.h> @@ -52,6 +54,7 @@ struct ltc4151_data { struct mutex update_lock; bool valid; unsigned long last_updated; /* in jiffies */ + unsigned int shunt; /* in micro ohms */ /* Registers */ u8 regs[6]; @@ -111,9 +114,9 @@ static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) case LTC4151_SENSE_H: /* * 20uV resolution. Convert to current as measured with - * an 1 mOhm sense resistor, in mA. + * a given sense resistor, in mA. */ - val = val * 20; + val = val * 20 * 1000 / data->shunt; break; case LTC4151_VIN_H: /* 25 mV per increment */ @@ -176,6 +179,7 @@ static int ltc4151_probe(struct i2c_client *client, struct device *dev = &client->dev; struct ltc4151_data *data; struct device *hwmon_dev; + u32 shunt; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) return -ENODEV; @@ -184,6 +188,14 @@ static int ltc4151_probe(struct i2c_client *client, if (!data) return -ENOMEM; +#ifdef CONFIG_OF + if (!of_property_read_u32(client->dev.of_node, "shunt-resistor", &shunt) + && shunt > 0 ) + data->shunt = shunt; + else +#endif + data->shunt = 1000; /* 1 mOhm if not set */ + data->client = client; mutex_init(&data->update_lock); @@ -199,10 +211,20 @@ static const struct i2c_device_id ltc4151_id[] = { }; MODULE_DEVICE_TABLE(i2c, ltc4151_id); +#ifdef CONFIG_OF +static const struct of_device_id ltc4151_match[] = { + { .compatible = "lltc,ltc4151" }, + {}, +}; +#endif + /* This is the driver that will be inserted */ static struct i2c_driver ltc4151_driver = { + .class = I2C_CLASS_HWMON, .driver = { .name = "ltc4151", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(ltc4151_match), }, .probe = ltc4151_probe, .id_table = ltc4151_id,
Allow to specify the resistance of the attached shunt via DT by adding the shunt-resistor property. Fall-back to the previous default (1 mOhm) if unset. Signed-off-by: Daniel Golle <daniel@makrotopia.org> --- drivers/hwmon/ltc4151.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-)