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hwmon: (ads7828) add support for ADS7830

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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@savoirfairelinux.com>
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guillaume Roguez 2012-10-03 16:54:08 -04:00 • committed by Guenter Roeck
parent 46d7846292
commit 0962e0f1a5
3 changed files with 32 additions and 11 deletions
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11
Documentation/hwmon/ads7828
View file

@ -7,9 +7,15 @@ Supported chips:
Datasheet: Publicly available at the Texas Instruments website:
http://focus.ti.com/lit/ds/symlink/ads7828.pdf
* Texas Instruments ADS7830
Prefix: 'ads7830'
Datasheet: Publicly available at the Texas Instruments website:
http://focus.ti.com/lit/ds/symlink/ads7830.pdf
Authors:
Steve Hardy <shardy@redhat.com>
Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
Platform data
-------------
@ -35,9 +41,10 @@ in include/linux/platform_data/ads7828.h). 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.

7
drivers/hwmon/Kconfig
View file

@ -1106,11 +1106,12 @@ 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.

25
drivers/hwmon/ads7828.c
View file

@ -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@redhat.com>
*
* ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
*
* 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 };
/* Client specific data */
struct ads7828_data {
struct device *hwmon_dev;
@ -55,6 +60,7 @@ 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 */
@ -78,8 +84,7 @@ 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;
@ -164,7 +169,14 @@ 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)
@ -191,7 +203,8 @@ error:
}
static const struct i2c_device_id ads7828_device_ids[] = {
{ "ads7828", 0 },
{ "ads7828", ads7828 },
{ "ads7830", ads7830 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
@ -210,4 +223,4 @@ module_i2c_driver(ads7828_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter");
MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");