From: Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
The ADS7830 device is almost the same as the ADS7828,
except that it does 8-bit sampling, instead of 12-bit.
This patch extends the ads7828 driver to support this chip.
Signed-off-by: Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/hwmon/ads7828 | 12 ++++++++++--
drivers/hwmon/Kconfig | 7 ++++---
drivers/hwmon/ads7828.c | 45 ++++++++++++++++++++++++++++++++++-----------
3 files changed, 48 insertions(+), 16 deletions(-)
diff --git a/Documentation/hwmon/ads7828 b/Documentation/hwmon/ads7828
index b35668c..51eab52 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>
Platform data
-------------
@@ -35,9 +42,10 @@ The structure fields are:
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 756bd1b..638c969 100644
--- a/drivers/hwmon/ads7828.c
+++ b/drivers/hwmon/ads7828.c
@@ -1,11 +1,13 @@
/*
- * ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC
+ * 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@xxxxxxxxxx>
*
+ * ADS7830 support, by Guillaume Roguez <guillaume.roguez@xxxxxxxxxxxxxxxxxxxx>
+ *
* For further information, see the Documentation/hwmon/ads7828 file.
*
* This program is free software; you can redistribute it and/or modify
@@ -43,6 +45,9 @@
#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 };
+
/* Addresses to scan */
static const unsigned short ads7828_normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
I2C_CLIENT_END };
@@ -59,6 +64,7 @@ struct ads7828_data {
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 */
+ s32 (*read_channel)(const struct i2c_client *client, u8 command);
};
/* Command byte C2,C1,C0 - see datasheet */
@@ -82,8 +88,7 @@ static struct ads7828_data *ads7828_update_device(struct device *dev)
for (ch = 0; ch < ADS7828_NCH; ch++) {
u8 cmd = ads7828_cmd_byte(data->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 = true;
@@ -147,6 +152,7 @@ static int ads7828_detect(struct i2c_client *client,
{
struct i2c_adapter *adapter = client->adapter;
u8 default_cmd_byte = ADS7828_CMD_SD_SE | ADS7828_CMD_PD3;
+ bool is_8bit = false;
int ch;
/* Check we have a valid client */
@@ -158,7 +164,9 @@ 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++) {
u8 cmd = ads7828_cmd_byte(default_cmd_byte, ch);
@@ -168,13 +176,20 @@ static int ads7828_detect(struct i2c_client *client,
return -ENODEV;
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;
}
@@ -206,7 +221,14 @@ static int ads7828_probe(struct i2c_client *client,
else
data->vref_mv = ADS7828_INT_VREF_MV;
- data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
+ /* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
+ if (id->driver_data == ads7828) {
+ data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
+ data->read_channel = i2c_smbus_read_word_swapped;
+ } else {
+ data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256);
+ data->read_channel = i2c_smbus_read_byte_data;
+ }
data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
if (!data->diff_input)
@@ -233,7 +255,8 @@ error:
}
static const struct i2c_device_id ads7828_device_ids[] = {
- { "ads7828", 0 },
+ { "ads7828", ads7828 },
+ { "ads7830", ads7830 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
@@ -254,4 +277,4 @@ module_i2c_driver(ads7828_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steve Hardy <shardy@xxxxxxxxxx>");
-MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter");
+MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
--
1.7.11.4
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