[PATCH] hwmon: (ads1015) Make gain and datarate configurable
Dirk Eibach
eibach at gdsys.de
Thu Mar 10 00:52:40 EST 2011
Signed-off-by: Dirk Eibach <eibach at gdsys.de>
---
.../devicetree/bindings/hwmon/ads1015.txt | 73 ++++++++++++++
Documentation/devicetree/bindings/i2c/ads1015.txt | 29 ------
Documentation/hwmon/ads1015 | 48 +++++++---
drivers/hwmon/ads1015.c | 104 ++++++++++++++++----
include/linux/i2c/ads1015.h | 8 ++
5 files changed, 202 insertions(+), 60 deletions(-)
create mode 100644 Documentation/devicetree/bindings/hwmon/ads1015.txt
delete mode 100644 Documentation/devicetree/bindings/i2c/ads1015.txt
diff --git a/Documentation/devicetree/bindings/hwmon/ads1015.txt b/Documentation/devicetree/bindings/hwmon/ads1015.txt
new file mode 100644
index 0000000..fb6e139
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/ads1015.txt
@@ -0,0 +1,73 @@
+ADS1015 (I2C)
+
+This device is a 12-bit A-D converter with 4 inputs.
+
+The inputs can be used single ended or in certain differential combinations.
+
+For configuration all possible combinations are mapped to 8 channels:
+ 0: Voltage over AIN0 and AIN1.
+ 1: Voltage over AIN0 and AIN3.
+ 2: Voltage over AIN1 and AIN3.
+ 3: Voltage over AIN2 and AIN3.
+ 4: Voltage over AIN0 and GND.
+ 5: Voltage over AIN1 and GND.
+ 6: Voltage over AIN2 and GND.
+ 7: Voltage over AIN3 and GND.
+
+Each channel can be configured indvidually:
+ - pga ist the programmable gain amplifier
+ 0: FS = +/- 6.144 V
+ 1: FS = +/- 4.096 V
+ 2: FS = +/- 2.048 V (default)
+ 3: FS = +/- 1.024 V
+ 4: FS = +/- 0.512 V
+ 5: FS = +/- 0.256 V
+ - data_rate in samples per second
+ 0: 128
+ 1: 250
+ 2: 490
+ 3: 920
+ 4: 1600
+ 5: 2400
+ 6: 3300
+
+1) The /ads1015 node
+
+ Required properties:
+
+ - compatible : must be "ti,ads1015"
+ - reg : I2C busaddress of the device
+ - #address-cells : must be <1>
+ - #size-cells : must be <0>
+
+ The node contains child nodes for each channel that the platform uses.
+
+ Example ADS1015 node:
+
+ ads1015 at 49 {
+ compatible = "ti,ads1015";
+ reg = <0x49>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ [ child node definitions... ]
+ }
+
+2) channel nodes
+
+ Required properties:
+
+ - reg : the channel number
+
+ Optional properties:
+
+ - ti,gain : the programmable gain amplifier setting
+ - ti,datarate : the converter datarate
+
+ Example ADS1015 node:
+
+ channel at 4 {
+ reg = <4>;
+ ti,gain = <3>;
+ ti,datarate = <5>;
+ };
diff --git a/Documentation/devicetree/bindings/i2c/ads1015.txt b/Documentation/devicetree/bindings/i2c/ads1015.txt
deleted file mode 100644
index 985e24d..0000000
--- a/Documentation/devicetree/bindings/i2c/ads1015.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-ADS1015 (I2C)
-
-This device is a 12-bit A-D converter with 4 inputs.
-
-The inputs can be used single ended or in certain differential combinations.
-
-For configuration all possible combinations are mapped to 8 channels:
-0: Voltage over AIN0 and AIN1.
-1: Voltage over AIN0 and AIN3.
-2: Voltage over AIN1 and AIN3.
-3: Voltage over AIN2 and AIN3.
-4: Voltage over AIN0 and GND.
-5: Voltage over AIN1 and GND.
-6: Voltage over AIN2 and GND.
-7: Voltage over AIN3 and GND.
-
-Optional properties:
-
- - exported-channels : exported_channels is a bitmask that specifies which
- channels should be accessible by the user.
-
-Example:
-ads1015 at 49 {
- compatible = "ti,ads1015";
- reg = <0x49>;
- exported-channels = <0x14>;
-};
-
-In this example only channel 2 and 4 would be accessible by the user.
diff --git a/Documentation/hwmon/ads1015 b/Documentation/hwmon/ads1015
index 56ee797..30250ca 100644
--- a/Documentation/hwmon/ads1015
+++ b/Documentation/hwmon/ads1015
@@ -38,30 +38,52 @@ Platform Data
In linux/i2c/ads1015.h platform data is defined as:
+struct ads1015_channel_data {
+ unsigned int pga;
+ unsigned int data_rate;
+};
+
struct ads1015_platform_data {
unsigned int exported_channels;
+ struct ads1015_channel_data channel_data[ADS1015_CONFIG_CHANNELS];
};
exported_channels is a bitmask that specifies which inputs should be exported.
+channel_data contains configuration data for the exported inputs:
+- pga ist the programmable gain amplifier
+ 0: FS = +/- 6.144 V
+ 1: FS = +/- 4.096 V
+ 2: FS = +/- 2.048 V (default)
+ 3: FS = +/- 1.024 V
+ 4: FS = +/- 0.512 V
+ 5: FS = +/- 0.256 V
+- data_rate in samples per second
+ 0: 128
+ 1: 250
+ 2: 490
+ 3: 920
+ 4: 1600
+ 5: 2400
+ 6: 3300
+
Example:
struct ads1015_platform_data data = {
- .exported_channels = (1 << 2) | (1 << 4)
+ .exported_channels = (1 << 2) | (1 << 4),
+ .channel_data = {
+ {},
+ {},
+ { .pga = 1, .data_rate = 0 },
+ {},
+ { .pga = 4, .data_rate = 5},
+ }
};
-In this case only in2_input and in4_input would be created.
+In this case only in2_input(FS +/- 4.096 V, 128 SPS) and in4_input
+(FS +/- 0.512 V, 2400 SPS) would be created.
Devicetree
----------
-The ads1015 node may have an "exported-channels" property.
-exported_channels is a bitmask that specifies which inputs should be exported.
-
-Example:
-ads1015 at 49 {
- compatible = "ti,ads1015";
- reg = <0x49>;
- exported-channels = < 0x14 >;
-};
-
-In this case only in2_input and in4_input would be created.
+Configuration is also possible via devicetree:
+Documentation/devicetree/bindings/hwmon/ads1015.txt
diff --git a/drivers/hwmon/ads1015.c b/drivers/hwmon/ads1015.c
index 8ef2b60..8657863 100644
--- a/drivers/hwmon/ads1015.c
+++ b/drivers/hwmon/ads1015.c
@@ -25,7 +25,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
-#include <linux/jiffies.h>
+#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
@@ -45,12 +45,18 @@ enum {
static const unsigned int fullscale_table[8] = {
6144, 4096, 2048, 1024, 512, 256, 256, 256 };
-#define ADS1015_CONFIG_CHANNELS 8
+/* Data rates in samples per second */
+static const unsigned int data_rate_table[8] = {
+ 128, 250, 490, 920, 1600, 2400, 3300, 3300 };
+
#define ADS1015_DEFAULT_CHANNELS 0xff
+#define ADS1015_DEFAULT_PGA 2
+#define ADS1015_DEFAULT_DATA_RATE 4
struct ads1015_data {
struct device *hwmon_dev;
struct mutex update_lock; /* mutex protect updates */
+ struct ads1015_channel_data channel_data[ADS1015_CONFIG_CHANNELS];
};
static s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg)
@@ -71,32 +77,38 @@ static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
{
u16 config;
s16 conversion;
- unsigned int pga;
+ struct ads1015_data *data = i2c_get_clientdata(client);
+ unsigned int pga = data->channel_data[channel].pga;
int fullscale;
+ unsigned int data_rate = data->channel_data[channel].data_rate;
+ unsigned int conversion_time_ms;
unsigned int k;
- struct ads1015_data *data = i2c_get_clientdata(client);
int res;
mutex_lock(&data->update_lock);
- /* get fullscale voltage */
+ /* get channel parameters */
res = ads1015_read_reg(client, ADS1015_CONFIG);
if (res < 0)
goto err_unlock;
config = res;
- pga = (config >> 9) & 0x0007;
fullscale = fullscale_table[pga];
+ conversion_time_ms = 1 + 1000 / data_rate_table[data_rate];
/* set channel and start single conversion */
- config &= ~(0x0007 << 12);
- config |= (1 << 15) | (1 << 8) | (channel & 0x0007) << 12;
+ config &= 0x001f;
+ config |= (1 << 15) | (1 << 8);
+ config |= (channel & 0x0007) << 12;
+ config |= (pga & 0x0007) << 9;
+ config |= (data_rate & 0x0007) << 5;
- /* wait until conversion finished */
res = ads1015_write_reg(client, ADS1015_CONFIG, config);
if (res < 0)
goto err_unlock;
+
+ /* wait until conversion finished */
for (k = 0; k < 5; ++k) {
- schedule_timeout(msecs_to_jiffies(1));
+ msleep(k ? 1 : conversion_time_ms);
res = ads1015_read_reg(client, ADS1015_CONFIG);
if (res < 0)
goto err_unlock;
@@ -168,26 +180,82 @@ static int ads1015_remove(struct i2c_client *client)
static unsigned int ads1015_get_exported_channels(struct i2c_client *client)
{
+ unsigned int k;
+ struct ads1015_data *data = i2c_get_clientdata(client);
struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
#ifdef CONFIG_OF
- struct device_node *np = client->dev.of_node;
- const __be32 *of_channels;
- int of_channels_size;
+ unsigned int of_exported_channels = 0;
+ struct device_node *node;
#endif
/* prefer platform data */
- if (pdata)
+ if (pdata) {
+ memcpy(data->channel_data, pdata->channel_data,
+ sizeof(data->channel_data));
return pdata->exported_channels;
+ }
#ifdef CONFIG_OF
/* fallback on OF */
- of_channels = of_get_property(np, "exported-channels",
- &of_channels_size);
- if (of_channels && (of_channels_size == sizeof(*of_channels)))
- return be32_to_cpup(of_channels);
+ if (!client->dev.of_node
+ || !of_get_next_child(client->dev.of_node, NULL))
+ goto fallback_default;
+
+ for_each_child_of_node(client->dev.of_node, node) {
+ const __be32 *property;
+ int len;
+ unsigned int channel;
+ unsigned int pga = ADS1015_DEFAULT_PGA;
+ unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
+
+ property = of_get_property(node, "reg", &len);
+ if (!property || (len < sizeof(int))) {
+ dev_err(&client->dev, "ads1015: invalid reg on %s\n",
+ node->full_name);
+ continue;
+ }
+
+ channel = be32_to_cpup(property);
+ if (channel > ADS1015_CONFIG_CHANNELS) {
+ dev_err(&client->dev, "ads1015: invalid addr=%x on %s\n",
+ channel, node->full_name);
+ continue;
+ }
+
+ property = of_get_property(node, "ti,gain", &len);
+ if (property && (len == sizeof(int))) {
+ pga = be32_to_cpup(property);
+ if (pga > 7) {
+ dev_err(&client->dev,
+ "ads1015: invalid gain on %s\n",
+ node->full_name);
+ }
+ }
+
+ property = of_get_property(node, "ti,datarate", &len);
+ if (property && (len == sizeof(int))) {
+ data_rate = be32_to_cpup(property);
+ if (data_rate > 7)
+ dev_err(&client->dev,
+ "ads1015: invalid data_rate on %s\n",
+ node->full_name);
+ }
+
+ of_exported_channels |= (1 << channel);
+ data->channel_data[channel].pga = pga;
+ data->channel_data[channel].data_rate = data_rate;
+ }
+
+ return of_exported_channels;
#endif
/* fallback on default configuration */
+fallback_default:
+ for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
+ data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
+ data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
+ }
+
return ADS1015_DEFAULT_CHANNELS;
}
diff --git a/include/linux/i2c/ads1015.h b/include/linux/i2c/ads1015.h
index 8541c6a..8f32040 100644
--- a/include/linux/i2c/ads1015.h
+++ b/include/linux/i2c/ads1015.h
@@ -21,8 +21,16 @@
#ifndef LINUX_ADS1015_H
#define LINUX_ADS1015_H
+#define ADS1015_CONFIG_CHANNELS 8
+
+struct ads1015_channel_data {
+ unsigned int pga;
+ unsigned int data_rate;
+};
+
struct ads1015_platform_data {
unsigned int exported_channels;
+ struct ads1015_channel_data channel_data[ADS1015_CONFIG_CHANNELS];
};
#endif /* LINUX_ADS1015_H */
--
1.5.6.5
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