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Commit 509416a8 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Guenter Roeck
Browse files

hwmon: (ina2xx) reinitialize the chip in case it's been reset 



Chips from the ina family don't like to be uninitialized. In case the power
is cut-off and restored again the calibration register will be reset
to 0 and both the power and current registers will remain at 0.

Check the calibration register in ina2xx_update_device() and reinitialize
the chip if needed.

Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 3c535bca

drivers/hwmon/ina2xx.c

+91 −37
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <linux/hwmon-sysfs.h>

#include <linux/jiffies.h>

#include <linux/of.h>

#include <linux/delay.h>



#include <linux/platform_data/ina2xx.h>
@@ -64,6 +65,9 @@ 


/* worst case is 68.10 ms (~14.6Hz, ina219) */

#define INA2XX_CONVERSION_RATE		15

#define INA2XX_MAX_DELAY		69 /* worst case delay in ms */



#define INA2XX_RSHUNT_DEFAULT		10000



enum ina2xx_ids { ina219, ina226 };
@@ -81,6 +85,8 @@ struct ina2xx_data { 
	struct i2c_client *client;

	const struct ina2xx_config *config;



	long rshunt;



	struct mutex update_lock;

	bool valid;

	unsigned long last_updated;
@@ -110,34 +116,96 @@ static const struct ina2xx_config ina2xx_config[] = { 
	},

};



static struct ina2xx_data *ina2xx_update_device(struct device *dev)

/*

 * Initialize the configuration and calibration registers.

 */

static int ina2xx_init(struct ina2xx_data *data)

{

	struct ina2xx_data *data = dev_get_drvdata(dev);

	struct i2c_client *client = data->client;

	struct ina2xx_data *ret = data;

	int ret;



	mutex_lock(&data->update_lock);

	/* device configuration */

	ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,

					   data->config->config_default);

	if (ret < 0)

		return ret;



	if (time_after(jiffies, data->last_updated +

		       HZ / INA2XX_CONVERSION_RATE) || !data->valid) {

	/*

	 * Set current LSB to 1mA, shunt is in uOhms

	 * (equation 13 in datasheet).

	 */

	return i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,

			data->config->calibration_factor / data->rshunt);

}



		int i;

static int ina2xx_do_update(struct device *dev)

{

	struct ina2xx_data *data = dev_get_drvdata(dev);

	struct i2c_client *client = data->client;

	int i, rv, retry;



	dev_dbg(&client->dev, "Starting ina2xx update\n");



	for (retry = 5; retry; retry--) {

		/* Read all registers */

		for (i = 0; i < data->config->registers; i++) {

			int rv = i2c_smbus_read_word_swapped(client, i);

			if (rv < 0) {

				ret = ERR_PTR(rv);

				goto abort;

			}

			rv = i2c_smbus_read_word_swapped(client, i);

			if (rv < 0)

				return rv;

			data->regs[i] = rv;

		}



		/*

		 * If the current value in the calibration register is 0, the

		 * power and current registers will also remain at 0. In case

		 * the chip has been reset let's check the calibration

		 * register and reinitialize if needed.

		 */

		if (data->regs[INA2XX_CALIBRATION] == 0) {

			dev_warn(dev, "chip not calibrated, reinitializing\n");



			rv = ina2xx_init(data);

			if (rv < 0)

				return rv;



			/*

			 * Let's make sure the power and current registers

			 * have been updated before trying again.

			 */

			msleep(INA2XX_MAX_DELAY);

			continue;

		}



		data->last_updated = jiffies;

		data->valid = 1;



		return 0;

	}

abort:



	/*

	 * If we're here then although all write operations succeeded, the

	 * chip still returns 0 in the calibration register. Nothing more we

	 * can do here.

	 */

	dev_err(dev, "unable to reinitialize the chip\n");

	return -ENODEV;

}



static struct ina2xx_data *ina2xx_update_device(struct device *dev)

{

	struct ina2xx_data *data = dev_get_drvdata(dev);

	struct ina2xx_data *ret = data;

	int rv;



	mutex_lock(&data->update_lock);



	if (time_after(jiffies, data->last_updated +

		       HZ / INA2XX_CONVERSION_RATE) || !data->valid) {

		rv = ina2xx_do_update(dev);

		if (rv < 0)

			ret = ERR_PTR(rv);

	}



	mutex_unlock(&data->update_lock);

	return ret;

}
@@ -221,7 +289,6 @@ 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;

	int ret;
@@ -234,41 +301,28 @@ 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)

		return -ENODEV;



	/* set the device type */

	data->kind = id->driver_data;

	data->config = &ina2xx_config[data->kind];

	data->client = client;



	/* device configuration */

	ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,

					   data->config->config_default);

	if (ret < 0) {

		dev_err(dev,

			"error writing to the config register: %d", ret);

	if (data->rshunt <= 0)

		return -ENODEV;

	}



	/*

	 * Set current LSB to 1mA, shunt is in uOhms

	 * (equation 13 in datasheet).

	 */

	ret = i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,

				data->config->calibration_factor / shunt);

	ret = ina2xx_init(data);

	if (ret < 0) {

		dev_err(dev,

			"error writing to the calibration register: %d", ret);

		dev_err(dev, "error configuring the device: %d\n", ret);

		return -ENODEV;

	}



	data->client = client;

	mutex_init(&data->update_lock);



	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
@@ -277,7 +331,7 @@ 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;

}