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authorSrikant Patnaik2015-01-11 12:28:04 +0530
committerSrikant Patnaik2015-01-11 12:28:04 +0530
commit871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch)
tree8718f573808810c2a1e8cb8fb6ac469093ca2784 /drivers/hwmon/ads7828.c
parent9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff)
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized. Changes are basically to make it look like kernel structure.
Diffstat (limited to 'drivers/hwmon/ads7828.c')
-rw-r--r--drivers/hwmon/ads7828.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
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+/*
+ * 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 <shardy@redhat.com>
+ *
+ * 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 };
+
+/* Module parameters */
+static bool se_input = 1; /* Default is SE, 0 == diff */
+static bool 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,
+ struct i2c_board_info *info);
+static int ads7828_probe(struct i2c_client *client,
+ const struct i2c_device_id *id);
+
+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] =
+ i2c_smbus_read_word_swapped(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", 0 },
+ { }
+};
+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_list = normal_i2c,
+};
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int ads7828_detect(struct i2c_client *client,
+ struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ int ch;
+
+ /* 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)
+ */
+ for (ch = 0; ch < ADS7828_NCH; ch++) {
+ u16 in_data;
+ u8 cmd = channel_cmd_byte(ch);
+ in_data = i2c_smbus_read_word_swapped(client, cmd);
+ if (in_data & 0xF000) {
+ pr_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 <shardy@redhat.com>");
+MODULE_DESCRIPTION("ADS7828 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_ads7828_init);
+module_exit(sensors_ads7828_exit);