Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751114AbaKYPrR (ORCPT ); Tue, 25 Nov 2014 10:47:17 -0500 Received: from mail-wi0-f181.google.com ([209.85.212.181]:44091 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750979AbaKYPrP (ORCPT ); Tue, 25 Nov 2014 10:47:15 -0500 From: Bartosz Golaszewski To: Guenter Roeck Cc: LKML , Benoit Cousson , Patrick Titiano , Bartosz Golaszewski Subject: [PATCH 2/5] hwmon: ina2xx: make shunt resistance configurable at run-time Date: Tue, 25 Nov 2014 16:47:00 +0100 Message-Id: <1416930423-12179-3-git-send-email-bgolaszewski@baylibre.com> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1416930423-12179-1-git-send-email-bgolaszewski@baylibre.com> References: <1416930423-12179-1-git-send-email-bgolaszewski@baylibre.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The shunt resistance can only be set via platform_data or device tree. This isn't suitable for devices in which the shunt resistance can change/isn't known at boot-time. Add a sysfs attribute that allows to read and set the shunt resistance. Signed-off-by: Bartosz Golaszewski --- drivers/hwmon/ina2xx.c | 58 ++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 51 insertions(+), 7 deletions(-) diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c index 660f8ca..eb66081 100644 --- a/drivers/hwmon/ina2xx.c +++ b/drivers/hwmon/ina2xx.c @@ -51,6 +51,8 @@ #define INA226_ALERT_LIMIT 0x07 #define INA226_DIE_ID 0xFF +/* shunt resistor sysfs attribute index */ +#define INA2XX_RSHUNT 0x8 /* register count */ #define INA219_REGISTERS 6 @@ -65,6 +67,9 @@ /* worst case is 68.10 ms (~14.6Hz, ina219) */ #define INA2XX_CONVERSION_RATE 15 +/* default shunt resistance */ +#define INA2XX_RSHUNT_DEFAULT 10000 + enum ina2xx_ids { ina219, ina226 }; struct ina2xx_config { @@ -87,6 +92,8 @@ struct ina2xx_data { int kind; u16 regs[INA2XX_MAX_REGISTERS]; + + long rshunt; }; static const struct ina2xx_config ina2xx_config[] = { @@ -110,6 +117,11 @@ static const struct ina2xx_config ina2xx_config[] = { }, }; +static u16 ina2xx_calibration_val(const struct ina2xx_data *data) +{ + return (u16)(data->config->calibration_factor / data->rshunt); +} + static int ina2xx_write_register(const struct i2c_client *client, u8 reg, u16 value) { @@ -198,6 +210,9 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg) /* signed register, LSB=1mA (selected), in mA */ val = (s16)data->regs[reg]; break; + case INA2XX_RSHUNT: + val = data->rshunt; + break; default: /* programmer goofed */ WARN_ON_ONCE(1); @@ -221,6 +236,30 @@ static ssize_t ina2xx_show_value(struct device *dev, ina2xx_get_value(data, attr->index)); } +static ssize_t ina2xx_set_shunt(struct device *dev, + struct device_attribute *da, + const char *buf, size_t count) +{ + struct ina2xx_data *data = ina2xx_update_device(dev); + long val; + s32 status; + + if (IS_ERR(data)) + return PTR_ERR(data); + + if ((kstrtol(buf, 10, &val) == -EINVAL) || (val <= 0)) + return -EINVAL; + + mutex_lock(&data->update_lock); + data->rshunt = val; + status = ina2xx_calibrate(data->client, ina2xx_calibration_val(data)); + mutex_unlock(&data->update_lock); + if (status < 0) + return -ENODEV; + + return count; +} + /* shunt voltage */ static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE); @@ -237,12 +276,17 @@ static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL, static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL, INA2XX_POWER); +/* shunt resistance */ +static SENSOR_DEVICE_ATTR(rshunt, S_IRUGO | S_IWUSR | S_IWGRP, + ina2xx_show_value, ina2xx_set_shunt, INA2XX_RSHUNT); + /* pointers to created device attributes */ static struct attribute *ina2xx_attrs[] = { &sensor_dev_attr_in0_input.dev_attr.attr, &sensor_dev_attr_in1_input.dev_attr.attr, &sensor_dev_attr_curr1_input.dev_attr.attr, &sensor_dev_attr_power1_input.dev_attr.attr, + &sensor_dev_attr_rshunt.dev_attr.attr, NULL, }; ATTRIBUTE_GROUPS(ina2xx); @@ -255,7 +299,6 @@ static int ina2xx_probe(struct i2c_client *client, struct device *dev = &client->dev; struct ina2xx_data *data; struct device *hwmon_dev; - long shunt = 10000; /* default shunt value 10mOhms */ u32 val; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) @@ -267,13 +310,15 @@ static int ina2xx_probe(struct i2c_client *client, if (dev_get_platdata(dev)) { pdata = dev_get_platdata(dev); - shunt = pdata->shunt_uohms; + data->rshunt = pdata->shunt_uohms; } else if (!of_property_read_u32(dev->of_node, "shunt-resistor", &val)) { - shunt = val; + data->rshunt = val; + } else { + data->rshunt = INA2XX_RSHUNT_DEFAULT; } - if (shunt <= 0) + if (data->rshunt <= 0) return -ENODEV; /* set the device type */ @@ -287,8 +332,7 @@ static int ina2xx_probe(struct i2c_client *client, /* Set current LSB to 1mA, shunt is in uOhms * (equation 13 in datasheet). */ - if (ina2xx_calibrate(client, - data->config->calibration_factor / shunt) < 0) + if (ina2xx_calibrate(client, ina2xx_calibration_val(data)) < 0) return -ENODEV; data->client = client; @@ -300,7 +344,7 @@ static int ina2xx_probe(struct i2c_client *client, return PTR_ERR(hwmon_dev); dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n", - id->name, shunt); + id->name, data->rshunt); return 0; } -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/