* Remove module parameters, add a ads7828_platform_data;
* Move driver declaration to avoid adding function prototypes;
* Remove unused macros;
* Coding Style fixes.
Signed-off-by: Vivien Didelot <[email protected]>
---
Documentation/hwmon/ads7828 | 31 +++--
drivers/hwmon/ads7828.c | 206 ++++++++++++++++------------------
include/linux/platform_data/ads7828.h | 29 +++++
3 files changed, 147 insertions(+), 119 deletions(-)
create mode 100644 include/linux/platform_data/ads7828.h
diff --git a/Documentation/hwmon/ads7828 b/Documentation/hwmon/ads7828
index 2bbebe6..b35668c 100644
--- a/Documentation/hwmon/ads7828
+++ b/Documentation/hwmon/ads7828
@@ -5,21 +5,32 @@ 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 <[email protected]>
-Module Parameters
------------------
-
-* 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
+Platform data
+-------------
+
+The ads7828 driver accepts an optional ads7828_platform_data structure (defined
+in include/linux/platform_data/ads7828.h). If no structure is provided, the
+configuration defaults to single ended operation and internal vref (2.5V).
+
+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: 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.
Description
-----------
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
index 1f9e8af..756bd1b 100644
--- a/drivers/hwmon/ads7828.c
+++ b/drivers/hwmon/ads7828.c
@@ -6,7 +6,7 @@
*
* Written by Steve Hardy <[email protected]>
*
- * 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 +23,48 @@
* 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 */
+#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 */
/* Addresses to scan */
-static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
+static const unsigned short ads7828_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 */
+/* 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 +81,12 @@ 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 +95,25 @@ 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,
@@ -152,35 +134,19 @@ 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;
+ u8 default_cmd_byte = ADS7828_CMD_SD_SE | ADS7828_CMD_PD3;
int ch;
/* Check we have a valid client */
@@ -195,9 +161,12 @@ static int ads7828_detect(struct i2c_client *client,
* - 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);
+ u8 cmd = ads7828_cmd_byte(default_cmd_byte, ch);
+ u16 in_data = i2c_smbus_read_word_swapped(client, cmd);
+
+ if (in_data < 0)
+ return -ENODEV;
+
if (in_data & 0xF000) {
pr_debug("%s : Doesn't look like an ads7828 device\n",
__func__);
@@ -213,6 +182,7 @@ 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 +191,30 @@ 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 +222,36 @@ 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;
-
- /* Calculate the LSB resolution */
- ads7828_lsb_resol = (vref_mv*1000)/4096;
+static const struct i2c_device_id ads7828_device_ids[] = {
+ { "ads7828", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
- return i2c_add_driver(&ads7828_driver);
-}
+static struct i2c_driver ads7828_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "ads7828",
+ },
+ .address_list = ads7828_normal_i2c,
+ .detect = ads7828_detect,
+ .probe = ads7828_probe,
+ .remove = ads7828_remove,
+ .id_table = ads7828_device_ids,
+};
-static void __exit sensors_ads7828_exit(void)
-{
- i2c_del_driver(&ads7828_driver);
-}
+module_i2c_driver(ads7828_driver);
-MODULE_AUTHOR("Steve Hardy <[email protected]>");
-MODULE_DESCRIPTION("ADS7828 driver");
MODULE_LICENSE("GPL");
-
-module_init(sensors_ads7828_init);
-module_exit(sensors_ads7828_exit);
+MODULE_AUTHOR("Steve Hardy <[email protected]>");
+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 0000000..3245f45
--- /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 <[email protected]>
+ *
+ * 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 */
--
1.7.11.4
From: Guillaume Roguez <[email protected]>
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 <[email protected]>
Signed-off-by: Vivien Didelot <[email protected]>
---
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 <[email protected]>
+ Guillaume Roguez <[email protected]>
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 <[email protected]>
*
+ * ADS7830 support, by Guillaume Roguez <[email protected]>
+ *
* 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 <[email protected]>");
-MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter");
+MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
--
1.7.11.4
On Tue, Oct 02, 2012 at 11:33:26PM -0400, Vivien Didelot wrote:
> * Remove module parameters, add a ads7828_platform_data;
> * Move driver declaration to avoid adding function prototypes;
> * Remove unused macros;
> * Coding Style fixes.
>
> Signed-off-by: Vivien Didelot <[email protected]>
Hi Vivien,
nice cleanup.
One more comment below. No need to re-send; I'll fix that and apply the patch to
-next.
Guenter
[ ... ]
> /* 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;
> + u8 default_cmd_byte = ADS7828_CMD_SD_SE | ADS7828_CMD_PD3;
> int ch;
>
> /* Check we have a valid client */
> @@ -195,9 +161,12 @@ static int ads7828_detect(struct i2c_client *client,
> * - 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);
> + u8 cmd = ads7828_cmd_byte(default_cmd_byte, ch);
> + u16 in_data = i2c_smbus_read_word_swapped(client, cmd);
s/u16/int/
Otherwise in_data can never be < 0.
Guenter
On Tue, Oct 02, 2012 at 11:33:27PM -0400, Vivien Didelot wrote:
> From: Guillaume Roguez <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Vivien Didelot <[email protected]>
Guillaume,
Vivien,
[ ... ]
> @@ -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;
> + }
> }
> }
I have been thinking about this. The detection function is already quite weak,
and this makes it even weaker. Reason is that you conly check for ADS7830 if the
check for ADS7828 failed, and you repeat the pattern for each channel.
Unfortunately, that means that you don't check for the ADS7830 condition if the
value returned for a channel happens to be a valid ADS7828 value, even if it is
not valid for ADS7830 (and even if you already know that the chip is not a
ADS7828).
Example:
ch=0: 0x1818 --> You know it is not ADS7828
ch=1: 0x0818 --> You know it is not ADS7830, but you don't check for it
I don't know an optimal solution right now, but maybe something like
maybe_7828 = true;
maybe_7830 = true;
for (ch = 0; ch < ADS7828_NCH && (maybe_7828 || maybe_7830); ch++) {
...
if (in_data & 0xF000)
maybe_7828 = false;
if ((in_data >> 8) != (in_data & 0xFF))
maybe_7830 = false;
}
if (!maybe_7828 && !maybe_7830)
return -ENODEV;
if (maybe_7828)
strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
else
strlcpy(info->type, "ads7830", I2C_NAME_SIZE);
Frankly I would prefer to get rid of the _detect function entirely, I just don't
know if that would negatively affect some users. To give you an example for a
bad result: The function will wrongly detect an ADS7830 as ADS7828 if all ADC
channels report a value between 0x00 and 0x0f.
How do you use the chip ? Do you need the detect function in your application ?
Thanks,
Guenter
Hi Guenter,
On Tue, 2012-10-02 at 22:07 -0700, Guenter Roeck wrote:
> On Tue, Oct 02, 2012 at 11:33:27PM -0400, Vivien Didelot wrote:
> > From: Guillaume Roguez <[email protected]>
> >
> > 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 <[email protected]>
> > Signed-off-by: Vivien Didelot <[email protected]>
>
> Guillaume,
> Vivien,
>
> [ ... ]
>
> > @@ -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;
> > + }
> > }
> > }
>
> I have been thinking about this. The detection function is already quite weak,
> and this makes it even weaker. Reason is that you conly check for ADS7830 if the
> check for ADS7828 failed, and you repeat the pattern for each channel.
> Unfortunately, that means that you don't check for the ADS7830 condition if the
> value returned for a channel happens to be a valid ADS7828 value, even if it is
> not valid for ADS7830 (and even if you already know that the chip is not a
> ADS7828).
>
> Example:
> ch=0: 0x1818 --> You know it is not ADS7828
> ch=1: 0x0818 --> You know it is not ADS7830, but you don't check for it
>
> I don't know an optimal solution right now, but maybe something like
>
> maybe_7828 = true;
> maybe_7830 = true;
> for (ch = 0; ch < ADS7828_NCH && (maybe_7828 || maybe_7830); ch++) {
> ...
> if (in_data & 0xF000)
> maybe_7828 = false;
> if ((in_data >> 8) != (in_data & 0xFF))
> maybe_7830 = false;
> }
> if (!maybe_7828 && !maybe_7830)
> return -ENODEV;
>
> if (maybe_7828)
> strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
> else
> strlcpy(info->type, "ads7830", I2C_NAME_SIZE);
>
> Frankly I would prefer to get rid of the _detect function entirely, I just don't
> know if that would negatively affect some users. To give you an example for a
> bad result: The function will wrongly detect an ADS7830 as ADS7828 if all ADC
> channels report a value between 0x00 and 0x0f.
We totally agree with you here. There is no clean way to detect (i.e. to
be sure) that this *is* an ADS7828 compatible device.
> How do you use the chip ? Do you need the detect function in your application ?
In our application, this device is statically declared in the platform
support code, so we don't need to "detect" it.
I propose to re-send a v5 with the "s/u16 in_data/int in_data/" fix and
the ads7828_detect() removal in the first cleanup patch, then the
ADS7830 support. Does it sound good for you?
Thanks,
Vivien
On Wed, Oct 03, 2012 at 10:03:08AM -0400, Vivien Didelot wrote:
> Hi Guenter,
>
> On Tue, 2012-10-02 at 22:07 -0700, Guenter Roeck wrote:
> > On Tue, Oct 02, 2012 at 11:33:27PM -0400, Vivien Didelot wrote:
> > > From: Guillaume Roguez <[email protected]>
> > >
> > > 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 <[email protected]>
> > > Signed-off-by: Vivien Didelot <[email protected]>
> >
> > Guillaume,
> > Vivien,
> >
> > [ ... ]
> >
> > > @@ -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;
> > > + }
> > > }
> > > }
> >
> > I have been thinking about this. The detection function is already quite weak,
> > and this makes it even weaker. Reason is that you conly check for ADS7830 if the
> > check for ADS7828 failed, and you repeat the pattern for each channel.
> > Unfortunately, that means that you don't check for the ADS7830 condition if the
> > value returned for a channel happens to be a valid ADS7828 value, even if it is
> > not valid for ADS7830 (and even if you already know that the chip is not a
> > ADS7828).
> >
> > Example:
> > ch=0: 0x1818 --> You know it is not ADS7828
> > ch=1: 0x0818 --> You know it is not ADS7830, but you don't check for it
> >
> > I don't know an optimal solution right now, but maybe something like
> >
> > maybe_7828 = true;
> > maybe_7830 = true;
> > for (ch = 0; ch < ADS7828_NCH && (maybe_7828 || maybe_7830); ch++) {
> > ...
> > if (in_data & 0xF000)
> > maybe_7828 = false;
> > if ((in_data >> 8) != (in_data & 0xFF))
> > maybe_7830 = false;
> > }
> > if (!maybe_7828 && !maybe_7830)
> > return -ENODEV;
> >
> > if (maybe_7828)
> > strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
> > else
> > strlcpy(info->type, "ads7830", I2C_NAME_SIZE);
> >
> > Frankly I would prefer to get rid of the _detect function entirely, I just don't
> > know if that would negatively affect some users. To give you an example for a
> > bad result: The function will wrongly detect an ADS7830 as ADS7828 if all ADC
> > channels report a value between 0x00 and 0x0f.
>
> We totally agree with you here. There is no clean way to detect (i.e. to
> be sure) that this *is* an ADS7828 compatible device.
>
> > How do you use the chip ? Do you need the detect function in your application ?
>
> In our application, this device is statically declared in the platform
> support code, so we don't need to "detect" it.
>
> I propose to re-send a v5 with the "s/u16 in_data/int in_data/" fix and
> the ads7828_detect() removal in the first cleanup patch, then the
> ADS7830 support. Does it sound good for you?
>
Yes.
Thanks,
Guenter