3 files changed, 140 insertions, 152 deletions

diff --git a/Documentation/hwmon/ads7828 b/Documentation/hwmon/ads7828
index 2bbebe6f771f..a987c94a88e5 100644
--- a/Documentation/hwmon/ads7828
+++ b/Documentation/hwmon/ads7828
@@ -4,22 +4,33 @@ Kernel driver ads7828
 Supported chips:
   * Texas Instruments/Burr-Brown ADS7828
     Prefix: 'ads7828'
-    Addresses scanned: I2C 0x48, 0x49, 0x4a, 0x4b
-    Datasheet: Publicly available at the Texas Instruments website :
+    Datasheet: Publicly available at the Texas Instruments website:
                http://focus.ti.com/lit/ds/symlink/ads7828.pdf
 
 Authors:
         Steve Hardy <shardy@redhat.com>
+        Vivien Didelot <vivien.didelot@savoirfairelinux.com>
 
-Module Parameters
------------------
+Platform data
+-------------
 
-* se_input: bool (default Y)
-  Single ended operation - set to N for differential mode
-* int_vref: bool (default Y)
-  Operate with the internal 2.5V reference - set to N for external reference
-* vref_mv: int (default 2500)
-  If using an external reference, set this to the reference voltage in mV
+The ads7828 driver accepts an optional ads7828_platform_data structure (defined
+in include/linux/platform_data/ads7828.h). The structure fields are:
+
+* diff_input: (bool) Differential operation
+  set to true for differential mode, false for default single ended mode.
+
+* ext_vref: (bool) External reference
+  set to true if it operates with an external reference, false for default
+  internal reference.
+
+* vref_mv: (unsigned int) Voltage reference
+  if using an external reference, set this to the reference voltage in mV,
+  otherwise it will default to the internal value (2500mV). This value will be
+  bounded with limits accepted by the chip, described in the datasheet.
+
+ If no structure is provided, the configuration defaults to single ended
+ operation and internal voltage reference (2.5V).
 
 Description
 -----------
@@ -34,3 +45,7 @@ where 4 differential pairs can be measured.
 The chip also has the facility to use an external voltage reference.  This
 may be required if your hardware supplies the ADS7828 from a 5V supply, see
 the datasheet for more details.
+
+There is no reliable way to identify this chip, so the driver will not scan
+some addresses to try to auto-detect it. That means that you will have to
+statically declare the device in the platform support code.
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
index 1f9e8af0f322..42914fc1436d 100644
--- a/drivers/hwmon/ads7828.c
+++ b/drivers/hwmon/ads7828.c
@@ -6,7 +6,7 @@
  *
  * Written by Steve Hardy <shardy@redhat.com>
  *
- * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf
+ * 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
@@ -23,63 +23,44 @@
  * 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/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
-#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/platform_data/ads7828.h>
+#include <linux/slab.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 */
+#define ADS7828_NCH             8       /* 8 channels supported */
+#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 */
+
+/* Client specific 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 */
+        struct mutex update_lock;       /* Mutex protecting updates */
+        unsigned long last_updated;     /* Last updated time (in jiffies) */
+        u16 adc_input[ADS7828_NCH];     /* ADS7828_NCH samples */
+        bool valid;                     /* Validity flag */
+        bool diff_input;                /* Differential input */
+        bool ext_vref;                  /* External voltage reference */
+        unsigned int vref_mv;           /* voltage reference value */
+        u8 cmd_byte;                    /* Command byte without channel bits */
+        unsigned int lsb_resol;         /* Resolution of the ADC sample LSB */
 };
 
-/* 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)
+/* Command byte C2,C1,C0 - see datasheet */
+static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
 {
-        /* cmd byte C2,C1,C0 - see datasheet */
-        u8 cmd = (((ch>>1) | (ch&0x01)<<2)<<4);
-        cmd |= ads7828_cmd_byte;
-        return cmd;
+        return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
 }
 
 /* Update data for the device (all 8 channels) */
@@ -96,12 +77,12 @@ static struct ads7828_data *ads7828_update_device(struct device *dev)
                 dev_dbg(&client->dev, "Starting ads7828 update\n");
 
                 for (ch = 0; ch < ADS7828_NCH; ch++) {
-                        u8 cmd = channel_cmd_byte(ch);
+                        u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch);
                         data->adc_input[ch] =
                                 i2c_smbus_read_word_swapped(client, cmd);
                 }
                 data->last_updated = jiffies;
-                data->valid = 1;
+                data->valid = true;
         }
 
         mutex_unlock(&data->update_lock);
@@ -110,28 +91,25 @@ static struct ads7828_data *ads7828_update_device(struct device *dev)
 }
 
 /* sysfs callback function */
-static ssize_t show_in(struct device *dev, struct device_attribute *da,
-        char *buf)
+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 = 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);
-}
+        unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] *
+                                               data->lsb_resol, 1000);
 
-#define in_reg(offset)\
-static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
-        NULL, offset)
+        return sprintf(buf, "%d\n", value);
+}
 
-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 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_attributes[] = {
         &sensor_dev_attr_in0_input.dev_attr.attr,
@@ -152,60 +130,9 @@ static const struct attribute_group ads7828_group = {
 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);
-        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;
 }
@@ -213,6 +140,7 @@ static int ads7828_detect(struct i2c_client *client,
 static int ads7828_probe(struct i2c_client *client,
                          const struct i2c_device_id *id)
 {
+        struct ads7828_platform_data *pdata = client->dev.platform_data;
         struct ads7828_data *data;
         int err;
 
@@ -221,10 +149,30 @@ static int ads7828_probe(struct i2c_client *client,
         if (!data)
                 return -ENOMEM;
 
+        if (pdata) {
+                data->diff_input = pdata->diff_input;
+                data->ext_vref = pdata->ext_vref;
+                if (data->ext_vref)
+                        data->vref_mv = pdata->vref_mv;
+        }
+
+        /* Bound Vref with min/max values if it was provided */
+        if (data->vref_mv)
+                data->vref_mv = SENSORS_LIMIT(data->vref_mv,
+                                              ADS7828_EXT_VREF_MV_MIN,
+                                              ADS7828_EXT_VREF_MV_MAX);
+        else
+                data->vref_mv = ADS7828_INT_VREF_MV;
+
+        data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
+
+        data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
+        if (!data->diff_input)
+                data->cmd_byte |= ADS7828_CMD_SD_SE;
+
         i2c_set_clientdata(client, data);
         mutex_init(&data->update_lock);
 
-        /* Register sysfs hooks */
         err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
         if (err)
                 return err;
@@ -232,38 +180,34 @@ static int ads7828_probe(struct i2c_client *client,
         data->hwmon_dev = hwmon_device_register(&client->dev);
         if (IS_ERR(data->hwmon_dev)) {
                 err = PTR_ERR(data->hwmon_dev);
-                goto exit_remove;
+                goto error;
         }
 
         return 0;
 
-exit_remove:
+error:
         sysfs_remove_group(&client->dev.kobj, &ads7828_group);
         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;
+static const struct i2c_device_id ads7828_device_ids[] = {
+        { "ads7828", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
 
-        /* Calculate the LSB resolution */
-        ads7828_lsb_resol = (vref_mv*1000)/4096;
+static struct i2c_driver ads7828_driver = {
+        .driver = {
+                .name = "ads7828",
+        },
 
-        return i2c_add_driver(&ads7828_driver);
-}
+        .id_table = ads7828_device_ids,
+        .probe = ads7828_probe,
+        .remove = ads7828_remove,
+};
 
-static void __exit sensors_ads7828_exit(void)
-{
-        i2c_del_driver(&ads7828_driver);
-}
+module_i2c_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);
+MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
+MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter");
diff --git a/include/linux/platform_data/ads7828.h b/include/linux/platform_data/ads7828.h
new file mode 100644
index 000000000000..3245f45f9d77
--- /dev/null
+++ b/include/linux/platform_data/ads7828.h
@@ -0,0 +1,29 @@
+/*
+ * TI ADS7828 A/D Converter platform data definition
+ *
+ * Copyright (c) 2012 Savoir-faire Linux Inc.
+ *          Vivien Didelot <vivien.didelot@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 version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _PDATA_ADS7828_H
+#define _PDATA_ADS7828_H
+
+/**
+ * struct ads7828_platform_data - optional ADS7828 connectivity info
+ * @diff_input:         Differential input mode.
+ * @ext_vref:           Use an external voltage reference.
+ * @vref_mv:            Voltage reference value, if external.
+ */
+struct ads7828_platform_data {
+        bool diff_input;
+        bool ext_vref;
+        unsigned int vref_mv;
+};
+
+#endif /* _PDATA_ADS7828_H */