From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH 1/2 v2] hwmon: (ltc4151) Make shunt-resistor configurable Date: Sat, 30 Jul 2016 09:00:14 -0700 Message-ID: <579CCF0E.9050506@roeck-us.net> References: <5795A144.2020300@roeck-us.net> <20160725115558.GA18360@makrotopia.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160725115558.GA18360-g5gK2j5usbvCyp4qypjU+w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Daniel Golle , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Axel Lin , =?UTF-8?Q?Per_Dal=c3=a9n?= List-Id: devicetree@vger.kernel.org Daniel, On 07/25/2016 04:56 AM, 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 Please resend with the property name changed as asked for by Rob. Thanks, Guenter > --- > v2: removed unneeded things and throw -EINVAL for shunt==0 > > drivers/hwmon/ltc4151.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/ltc4151.c b/drivers/hwmon/ltc4151.c > index c86a184..419c6f7 100644 > --- a/drivers/hwmon/ltc4151.c > +++ b/drivers/hwmon/ltc4151.c > @@ -30,6 +30,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -52,6 +53,7 @@ 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 +113,9 @@ 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 +178,7 @@ 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 +187,14 @@ static int ltc4151_probe(struct i2c_client *client, > if (!data) > return -ENOMEM; > > + if (of_property_read_u32(client->dev.of_node, "shunt-resistor", &shunt)) > + shunt = 1000; /* 1 mOhm if not set via DT */ > + > + if (shunt == 0) > + return -EINVAL; > + > + data->shunt = shunt; > + > data->client = client; > mutex_init(&data->update_lock); > > @@ -199,10 +210,16 @@ static const struct i2c_device_id ltc4151_id[] = { > }; > MODULE_DEVICE_TABLE(i2c, ltc4151_id); > > +static const struct of_device_id ltc4151_match[] = { > + { .compatible = "lltc,ltc4151" }, > + {}, > +}; > + > /* This is the driver that will be inserted */ > static struct i2c_driver ltc4151_driver = { > .driver = { > .name = "ltc4151", > + .of_match_table = of_match_ptr(ltc4151_match), > }, > .probe = ltc4151_probe, > .id_table = ltc4151_id, > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html