hwmon: Add support for Texas Instruments ADS1015

Signed-off-by: Dirk Eibach <eibach@gdsys.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 282 insertions, 0 deletions

diff --git a/drivers/hwmon/ads1015.c b/drivers/hwmon/ads1015.c
new file mode 100644
index 0000000..9e1585c
--- /dev/null
+++ b/drivers/hwmon/ads1015.c
@@ -0,0 +1,282 @@
+/*
+ * ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
+ * (C) Copyright 2010
+ * Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
+ *
+ * Based on the ads7828 driver by Steve Hardy.
+ *
+ * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+
+#include <linux/i2c/ads1015.h>
+
+/* ADS1015 registers */
+enum {
+	ADS1015_CONVERSION = 0,
+	ADS1015_CONFIG = 1,
+};
+
+/* PGA fullscale voltages in mV */
+static const unsigned int fullscale_table[8] = {
+	6144, 4096, 2048, 1024, 512, 256, 256, 256 };
+
+#define ADS1015_CONFIG_CHANNELS 8
+#define ADS1015_DEFAULT_CHANNELS 0xff
+
+struct ads1015_data {
+	struct device *hwmon_dev;
+	struct mutex update_lock; /* mutex protect updates */
+	struct attribute *attr_table[ADS1015_CONFIG_CHANNELS + 1];
+	struct attribute_group attr_group;
+};
+
+static s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg)
+{
+	s32 data = i2c_smbus_read_word_data(client, reg);
+
+	return (data < 0) ? data : swab16(data);
+}
+
+static s32 ads1015_write_reg(struct i2c_client *client, unsigned int reg,
+			     u16 val)
+{
+	return i2c_smbus_write_word_data(client, reg, swab16(val));
+}
+
+static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
+			      int *value)
+{
+	u16 config;
+	s16 conversion;
+	unsigned int pga;
+	int fullscale;
+	unsigned int k;
+	struct ads1015_data *data = i2c_get_clientdata(client);
+	int res;
+
+	mutex_lock(&data->update_lock);
+
+	/* get fullscale voltage */
+	res = ads1015_read_reg(client, ADS1015_CONFIG);
+	if (res < 0)
+		goto err_unlock;
+	config = res;
+	pga = (config >> 9) & 0x0007;
+	fullscale = fullscale_table[pga];
+
+	/* set channel and start single conversion */
+	config &= ~(0x0007 << 12);
+	config |= (1 << 15) | (1 << 8) | (channel & 0x0007) << 12;
+
+	/* wait until conversion finished */
+	res = ads1015_write_reg(client, ADS1015_CONFIG, config);
+	if (res < 0)
+		goto err_unlock;
+	for (k = 0; k < 5; ++k) {
+		msleep(1);
+		res = ads1015_read_reg(client, ADS1015_CONFIG);
+		if (res < 0)
+			goto err_unlock;
+		config = res;
+		if (config & (1 << 15))
+			break;
+	}
+	if (k == 5) {
+		res = -EIO;
+		goto err_unlock;
+	}
+
+	res = ads1015_read_reg(client, ADS1015_CONVERSION);
+	if (res < 0)
+		goto err_unlock;
+	conversion = res;
+
+	mutex_unlock(&data->update_lock);
+
+	*value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);
+
+	return 0;
+
+err_unlock:
+	mutex_unlock(&data->update_lock);
+	return res;
+}
+
+/* sysfs callback function */
+static ssize_t show_in(struct device *dev, struct device_attribute *da,
+	char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct i2c_client *client = to_i2c_client(dev);
+	int in;
+	int res;
+
+	res = ads1015_read_value(client, attr->index, &in);
+
+	return (res < 0) ? res : sprintf(buf, "%d\n", in);
+}
+
+#define in_reg(offset)\
+static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
+	NULL, offset)
+
+in_reg(0);
+in_reg(1);
+in_reg(2);
+in_reg(3);
+in_reg(4);
+in_reg(5);
+in_reg(6);
+in_reg(7);
+
+static struct attribute *all_attributes[] = {
+	&sensor_dev_attr_in0_input.dev_attr.attr,
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+	&sensor_dev_attr_in7_input.dev_attr.attr,
+};
+
+/*
+ * Driver interface
+ */
+
+static int ads1015_remove(struct i2c_client *client)
+{
+	struct ads1015_data *data = i2c_get_clientdata(client);
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &data->attr_group);
+	kfree(data);
+	return 0;
+}
+
+static unsigned int ads1015_get_exported_channels(struct i2c_client *client)
+{
+	struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
+#ifdef CONFIG_OF
+	struct device_node *np = client->dev.of_node;
+	const __be32 *of_channels;
+	int of_channels_size;
+#endif
+
+	/* prefer platform data */
+	if (pdata)
+		return pdata->exported_channels;
+
+#ifdef CONFIG_OF
+	/* fallback on OF */
+	of_channels = of_get_property(np, "exported-channels",
+				      &of_channels_size);
+	if (of_channels && (of_channels_size == sizeof(*of_channels)))
+		return be32_to_cpup(of_channels);
+#endif
+
+	/* fallback on default configuration */
+	return ADS1015_DEFAULT_CHANNELS;
+}
+
+static int ads1015_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct ads1015_data *data;
+	int err;
+	unsigned int exported_channels;
+	unsigned int k;
+	unsigned int n = 0;
+
+	data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
+	if (!data) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/* build sysfs attribute group */
+	data->attr_group.attrs = data->attr_table;
+	exported_channels = ads1015_get_exported_channels(client);
+	for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
+		if (!(exported_channels & (1<<k)))
+			continue;
+		data->attr_table[n++] = all_attributes[k];
+	}
+	err = sysfs_create_group(&client->dev.kobj, &data->attr_group);
+	if (err)
+		goto exit_free;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		err = PTR_ERR(data->hwmon_dev);
+		goto exit_remove;
+	}
+
+	return 0;
+
+exit_remove:
+	sysfs_remove_group(&client->dev.kobj, &data->attr_group);
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static const struct i2c_device_id ads1015_id[] = {
+	{ "ads1015", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ads1015_id);
+
+static struct i2c_driver ads1015_driver = {
+	.driver = {
+		.name = "ads1015",
+	},
+	.probe = ads1015_probe,
+	.remove = ads1015_remove,
+	.id_table = ads1015_id,
+};
+
+static int __init sensors_ads1015_init(void)
+{
+	return i2c_add_driver(&ads1015_driver);
+}
+
+static void __exit sensors_ads1015_exit(void)
+{
+	i2c_del_driver(&ads1015_driver);
+}
+
+MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
+MODULE_DESCRIPTION("ADS1015 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_ads1015_init);
+module_exit(sensors_ads1015_exit);