Initial import

1 files changed, 183 insertions, 0 deletions

diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
new file mode 100644
index 000000000..6c99ee7ba
--- /dev/null
+++ b/drivers/hwmon/ads7828.c
@@ -0,0 +1,183 @@
+/*
+ * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
+ * (C) 2007 EADS Astrium
+ *
+ * This driver is based on the lm75 and other lm_sensors/hwmon drivers
+ *
+ * Written by Steve Hardy <shardy@redhat.com>
+ *
+ * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
+ *
+ * For further information, see the Documentation/hwmon/ads7828 file.
+ *
+ * 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/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_data/ads7828.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* The ADS7828 registers */
+#define ADS7828_CMD_SD_SE	0x80	/* Single ended inputs */
+#define ADS7828_CMD_PD1		0x04	/* Internal vref OFF && A/D ON */
+#define ADS7828_CMD_PD3		0x0C	/* Internal vref ON && A/D ON */
+#define ADS7828_INT_VREF_MV	2500	/* Internal vref is 2.5V, 2500mV */
+#define ADS7828_EXT_VREF_MV_MIN	50	/* External vref min value 0.05V */
+#define ADS7828_EXT_VREF_MV_MAX	5250	/* External vref max value 5.25V */
+
+/* List of supported devices */
+enum ads7828_chips { ads7828, ads7830 };
+
+/* Client specific data */
+struct ads7828_data {
+	struct regmap *regmap;
+	u8 cmd_byte;			/* Command byte without channel bits */
+	unsigned int lsb_resol;		/* Resolution of the ADC sample LSB */
+};
+
+/* Command byte C2,C1,C0 - see datasheet */
+static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
+{
+	return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
+}
+
+/* sysfs callback function */
+static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da,
+			       char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ads7828_data *data = dev_get_drvdata(dev);
+	u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
+	unsigned int regval;
+	int err;
+
+	err = regmap_read(data->regmap, cmd, &regval);
+	if (err < 0)
+		return err;
+
+	return sprintf(buf, "%d\n",
+		       DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
+}
+
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
+static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);
+
+static struct attribute *ads7828_attrs[] = {
+	&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,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(ads7828);
+
+static const struct regmap_config ads2828_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+};
+
+static const struct regmap_config ads2830_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int ads7828_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ads7828_platform_data *pdata = dev_get_platdata(dev);
+	struct ads7828_data *data;
+	struct device *hwmon_dev;
+	unsigned int vref_mv = ADS7828_INT_VREF_MV;
+	bool diff_input = false;
+	bool ext_vref = false;
+
+	data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	if (pdata) {
+		diff_input = pdata->diff_input;
+		ext_vref = pdata->ext_vref;
+		if (ext_vref && pdata->vref_mv)
+			vref_mv = pdata->vref_mv;
+	}
+
+	/* Bound Vref with min/max values */
+	vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
+			    ADS7828_EXT_VREF_MV_MAX);
+
+	/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
+	if (id->driver_data == ads7828) {
+		data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
+		data->regmap = devm_regmap_init_i2c(client,
+						    &ads2828_regmap_config);
+	} else {
+		data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
+		data->regmap = devm_regmap_init_i2c(client,
+						    &ads2830_regmap_config);
+	}
+
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
+	data->cmd_byte = ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
+	if (!diff_input)
+		data->cmd_byte |= ADS7828_CMD_SD_SE;
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+							   data,
+							   ads7828_groups);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ads7828_device_ids[] = {
+	{ "ads7828", ads7828 },
+	{ "ads7830", ads7830 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
+
+static struct i2c_driver ads7828_driver = {
+	.driver = {
+		.name = "ads7828",
+	},
+
+	.id_table = ads7828_device_ids,
+	.probe = ads7828_probe,
+};
+
+module_i2c_driver(ads7828_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
+MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");