[PATCH] hwmon: (ads7828) add support for ADS7830
From: Vivien Didelot
Date: Mon Oct 01 2012 - 16:58:17 EST
From: Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
The ADS7830 is almost the same chip, except that it does 8-bit sampling.
This patch extends the ads7828 driver to support this device.
Signed-off-by: Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
Also clean the driver a bit by removing unused macros, and moving
the driver declaration to avoid some function prototypes.
Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/hwmon/ads7828 | 12 +++-
drivers/hwmon/Kconfig | 7 ++-
drivers/hwmon/ads7828.c | 137 +++++++++++++++++++++++++-------------------
3 files changed, 93 insertions(+), 63 deletions(-)
diff --git a/Documentation/hwmon/ads7828 b/Documentation/hwmon/ads7828
index 2bbebe6..4366a87 100644
--- a/Documentation/hwmon/ads7828
+++ b/Documentation/hwmon/ads7828
@@ -8,8 +8,15 @@ Supported chips:
Datasheet: Publicly available at the Texas Instruments website :
http://focus.ti.com/lit/ds/symlink/ads7828.pdf
+ * Texas Instruments ADS7830
+ Prefix: 'ads7830'
+ Addresses scanned: I2C 0x48, 0x49, 0x4a, 0x4b
+ Datasheet: Publicly available at the Texas Instruments website:
+ http://focus.ti.com/lit/ds/symlink/ads7830.pdf
+
Authors:
Steve Hardy <shardy@xxxxxxxxxx>
+ Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
Module Parameters
-----------------
@@ -24,9 +31,10 @@ Module Parameters
Description
-----------
-This driver implements support for the Texas Instruments ADS7828.
+This driver implements support for the Texas Instruments ADS7828, and ADS7830.
-This device is a 12-bit 8-channel A-D converter.
+The ADS7828 device is a 12-bit 8-channel A/D converter, while the ADS7830 does
+8-bit sampling.
It can operate in single ended mode (8 +ve inputs) or in differential mode,
where 4 differential pairs can be measured.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 83e3e9d..960c8c5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1060,11 +1060,12 @@ config SENSORS_ADS1015
will be called ads1015.
config SENSORS_ADS7828
- tristate "Texas Instruments ADS7828"
+ tristate "Texas Instruments ADS7828 and compatibles"
depends on I2C
help
- If you say yes here you get support for Texas Instruments ADS7828
- 12-bit 8-channel ADC device.
+ If you say yes here you get support for Texas Instruments ADS7828 and
+ ADS7830 8-channel A/D converters. ADS7828 resolution is 12-bit, while
+ it is 8-bit on ADS7830.
This driver can also be built as a module. If so, the module
will be called ads7828.
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
index bf3fdf4..58f28ea 100644
--- a/drivers/hwmon/ads7828.c
+++ b/drivers/hwmon/ads7828.c
@@ -1,12 +1,12 @@
/*
- * ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC
- * (C) 2007 EADS Astrium
+ * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
*
- * This driver is based on the lm75 and other lm_sensors/hwmon drivers
+ * Copyright (C) 2007 EADS Astrium
+ * Copyright (C) Steve Hardy <shardy@xxxxxxxxxx>
+ * Copyright (C) 2012 Savoir-faire Linux Inc.
+ * Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
*
- * Written by Steve Hardy <shardy@xxxxxxxxxx>
- *
- * 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
@@ -34,14 +34,15 @@
#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 */
+#define ADS7828_NCH 8 /* 8 channels supported */
+#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
+#define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */
+#define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A/D ON */
+#define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A/D ON */
+#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
+
+/* List of supported devices */
+enum ads7828_chips { ads7828, ads7830 };
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
@@ -57,23 +58,27 @@ 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 - client specific data
+ * @hwmon_dev: The hwmon device.
+ * @update_lock: Mutex protecting updates.
+ * @valid: Validity flag.
+ * @last_updated: Last updated time (in jiffies).
+ * @adc_input: ADS7828_NCH samples.
+ * @lsb_resol: Resolution of the A/D converter sample LSB.
+ * @read_channel: Function used to read a channel.
+ */
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;
+ char valid;
+ unsigned long last_updated;
+ u16 adc_input[ADS7828_NCH];
+ unsigned int lsb_resol;
+ s32 (*read_channel)(const struct i2c_client *client, u8 command);
};
-/* 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 */
@@ -97,8 +102,7 @@ static struct ads7828_data *ads7828_update_device(struct device *dev)
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->adc_input[ch] = data->read_channel(client, cmd);
}
data->last_updated = jiffies;
data->valid = 1;
@@ -116,8 +120,8 @@ static ssize_t show_in(struct device *dev, struct device_attribute *da,
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);
+ return sprintf(buf, "%d\n",
+ (data->adc_input[attr->index] * data->lsb_resol) / 1000);
}
#define in_reg(offset)\
@@ -158,31 +162,13 @@ static int ads7828_remove(struct i2c_client *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;
+ bool is_8bit = false;
/* Check we have a valid client */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
@@ -193,20 +179,30 @@ static int ads7828_detect(struct i2c_client *client,
* 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)
+ * - Check the top 4 bits of each result:
+ * - They should not be set in case of 12-bit samples
+ * - The two bytes should be equal in case of 8-bit samples
*/
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;
+ if ((in_data >> 8) == (in_data & 0xFF)) {
+ /* Seems to be an ADS7830 (8-bit sample) */
+ is_8bit = true;
+ } else {
+ dev_dbg(&client->dev, "doesn't look like an "
+ "ADS7828 compatible device\n");
+ return -ENODEV;
+ }
}
}
- strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
+ if (is_8bit)
+ strlcpy(info->type, "ads7830", I2C_NAME_SIZE);
+ else
+ strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
return 0;
}
@@ -223,6 +219,15 @@ static int ads7828_probe(struct i2c_client *client,
goto exit;
}
+ /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
+ if (id->driver_data == ads7828) {
+ data->read_channel = i2c_smbus_read_word_swapped;
+ data->lsb_resol = (vref_mv * 1000) / 4096;
+ } else {
+ data->read_channel = i2c_smbus_read_byte_data;
+ data->lsb_resol = (vref_mv * 1000) / 256;
+ }
+
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
@@ -247,6 +252,25 @@ exit:
return err;
}
+static const struct i2c_device_id ads7828_ids[] = {
+ { "ads7828", ads7828 },
+ { "ads7830", ads7830 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ads7828_ids);
+
+static struct i2c_driver ads7828_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "ads7828",
+ },
+ .probe = ads7828_probe,
+ .remove = ads7828_remove,
+ .id_table = ads7828_ids,
+ .detect = ads7828_detect,
+ .address_list = normal_i2c,
+};
+
static int __init sensors_ads7828_init(void)
{
/* Initialize the command byte according to module parameters */
@@ -255,9 +279,6 @@ static int __init sensors_ads7828_init(void)
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);
}
@@ -267,7 +288,7 @@ static void __exit sensors_ads7828_exit(void)
}
MODULE_AUTHOR("Steve Hardy <shardy@xxxxxxxxxx>");
-MODULE_DESCRIPTION("ADS7828 driver");
+MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
MODULE_LICENSE("GPL");
module_init(sensors_ads7828_init);
--
1.7.11.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/