1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
new file mode 100644
index 0000000..5c39b4a
--- /dev/null
+++ b/drivers/hwmon/ads7828.c
@@ -0,0 +1,284 @@
+/*
+	ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC
+	(C) 2007 EADS Astrium
+
+	This driver is based on the lm75 and other lm_sensors/hwmon drivers
+
+	Written by Steve Hardy <steve@linuxrealtime.co.uk>
+
+	Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.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/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+
+/* The ADS7828 registers */
+#define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */
+#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
+#define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */
+#define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */
+#define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */
+#define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */
+#define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */
+#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
+	I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_1(ads7828);
+
+/* Other module parameters */
+static int se_input = 1; /* Default is SE, 0 == diff */
+static int int_vref = 1; /* Default is internal ref ON */
+static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */
+module_param(se_input, bool, S_IRUGO);
+module_param(int_vref, bool, S_IRUGO);
+module_param(vref_mv, int, S_IRUGO);
+
+/* Global Variables */
+static u8 ads7828_cmd_byte; /* cmd byte without channel bits */
+static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */
+
+/* Each client has this additional data */
+struct ads7828_data {
+	struct device *hwmon_dev;
+	struct mutex update_lock; /* mutex protect updates */
+	char valid; /* !=0 if following fields are valid */
+	unsigned long last_updated; /* In jiffies */
+	u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */
+};
+
+/* Function declaration - necessary due to function dependencies */
+static int ads7828_detect(struct i2c_client *client, int kind,
+			  struct i2c_board_info *info);
+static int ads7828_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id);
+
+/* The ADS7828 returns the 12-bit sample in two bytes,
+	these are read as a word then byte-swapped */
+static u16 ads7828_read_value(struct i2c_client *client, u8 reg)
+{
+	return swab16(i2c_smbus_read_word_data(client, reg));
+}
+
+static inline u8 channel_cmd_byte(int ch)
+{
+	/* cmd byte C2,C1,C0 - see datasheet */
+	u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4);
+	cmd |= ads7828_cmd_byte;
+	return cmd;
+}
+
+/* Update data for the device (all 8 channels) */
+static struct ads7828_data *ads7828_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ads7828_data *data = i2c_get_clientdata(client);
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
+			|| !data->valid) {
+		unsigned int ch;
+		dev_dbg(&client->dev, "Starting ads7828 update\n");
+
+		for (ch = 0; ch < ADS7828_NCH; ch++) {
+			u8 cmd = channel_cmd_byte(ch);
+			data->adc_input[ch] = ads7828_read_value(client, cmd);
+		}
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+/* 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 ads7828_data *data = ads7828_update_device(dev);
+	/* Print value (in mV as specified in sysfs-interface documentation) */
+	return sprintf(buf, "%d\n", (data->adc_input[attr->index] *
+		ads7828_lsb_resol)/1000);
+}
+
+#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 *ads7828_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,
+	NULL
+};
+
+static const struct attribute_group ads7828_group = {
+	.attrs = ads7828_attributes,
+};
+
+static int ads7828_remove(struct i2c_client *client)
+{
+	struct ads7828_data *data = i2c_get_clientdata(client);
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
+	kfree(i2c_get_clientdata(client));
+	return 0;
+}
+
+static const struct i2c_device_id ads7828_id[] = {
+	{ "ads7828", ads7828 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ads7828_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ads7828_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name = "ads7828",
+	},
+	.probe = ads7828_probe,
+	.remove = ads7828_remove,
+	.id_table = ads7828_id,
+	.detect = ads7828_detect,
+	.address_data = &addr_data,
+};
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int ads7828_detect(struct i2c_client *client, int kind,
+			  struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+
+	/* Check we have a valid client */
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
+		return -ENODEV;
+
+	/* Now, we do the remaining detection. There is no identification
+	dedicated register so attempt to sanity check using knowledge of
+	the chip
+	- Read from the 8 channel addresses
+	- Check the top 4 bits of each result are not set (12 data bits)
+	*/
+	if (kind < 0) {
+		int ch;
+		for (ch = 0; ch < ADS7828_NCH; ch++) {
+			u16 in_data;
+			u8 cmd = channel_cmd_byte(ch);
+			in_data = ads7828_read_value(client, cmd);
+			if (in_data & 0xF000) {
+				printk(KERN_DEBUG
+				"%s : Doesn't look like an ads7828 device\n",
+				__func__);
+				return -ENODEV;
+			}
+		}
+	}
+	strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int ads7828_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct ads7828_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL);
+	if (!data) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/* Register sysfs hooks */
+	err = sysfs_create_group(&client->dev.kobj, &ads7828_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, &ads7828_group);
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int __init sensors_ads7828_init(void)
+{
+	/* Initialize the command byte according to module parameters */
+	ads7828_cmd_byte = se_input ?
+		ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF;
+	ads7828_cmd_byte |= int_vref ?
+		ADS7828_CMD_PD3 : ADS7828_CMD_PD1;
+
+	/* Calculate the LSB resolution */
+	ads7828_lsb_resol = (vref_mv*1000)/4096;
+
+	return i2c_add_driver(&ads7828_driver);
+}
+
+static void __exit sensors_ads7828_exit(void)
+{
+	i2c_del_driver(&ads7828_driver);
+}
+
+MODULE_AUTHOR("Steve Hardy <steve@linuxrealtime.co.uk>");
+MODULE_DESCRIPTION("ADS7828 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_ads7828_init);
+module_exit(sensors_ads7828_exit);