[PATCH v2] hwmon: (ads1015) Make gain and datarate configurable
Grant Likely
grant.likely at secretlab.ca
Thu Mar 17 07:46:44 EST 2011
On Wed, Mar 16, 2011 at 11:01:55AM +0100, Dirk Eibach wrote:
> Configuration for ads1015 gain and datarate is possible via
> devicetree or platform data.
>
> This is a followup patch to previous ads1015 patches on Jean Delvares
> tree.
>
> Changes since v1:
> - replaced exported_channels bitmask with an enable entry per channel
> - improved platform data example in Documentation
> - improved patch description
>
> Signed-off-by: Dirk Eibach <eibach at gdsys.de>
Acked-by: Grant Likely <grant.likely at secretlab.ca>
> ---
> .../devicetree/bindings/hwmon/ads1015.txt | 73 +++++++++++++
> Documentation/devicetree/bindings/i2c/ads1015.txt | 29 -----
> Documentation/hwmon/ads1015 | 44 ++++++---
> drivers/hwmon/ads1015.c | 113 +++++++++++++++----
> include/linux/i2c/ads1015.h | 10 ++-
> 5 files changed, 202 insertions(+), 67 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..18a8e00 100644
> --- a/Documentation/hwmon/ads1015
> +++ b/Documentation/hwmon/ads1015
> @@ -38,30 +38,48 @@ 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)
> + .channel_data = {
> + [2] = { .enabled = true, .pga = 1, .data_rate = 0 },
> + [4] = { .enabled = true, .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..a7c524d 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;
> @@ -166,29 +178,83 @@ static int ads1015_remove(struct i2c_client *client)
> return 0;
> }
>
> -static unsigned int ads1015_get_exported_channels(struct i2c_client *client)
> +static void 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;
> + struct device_node *node;
> #endif
>
> /* prefer platform data */
> - if (pdata)
> - return pdata->exported_channels;
> + if (pdata) {
> + memcpy(data->channel_data, pdata->channel_data,
> + sizeof(data->channel_data));
> + return;
> + }
>
> #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);
> + }
> +
> + data->channel_data[channel].enabled = true;
> + data->channel_data[channel].pga = pga;
> + data->channel_data[channel].data_rate = data_rate;
> + }
> +
> + return;
> #endif
>
> /* fallback on default configuration */
> - return ADS1015_DEFAULT_CHANNELS;
> +fallback_default:
> + for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
> + data->channel_data[k].enabled = true;
> + data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
> + data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
> + }
> }
>
> static int ads1015_probe(struct i2c_client *client,
> @@ -196,7 +262,6 @@ static int ads1015_probe(struct i2c_client *client,
> {
> struct ads1015_data *data;
> int err;
> - unsigned int exported_channels;
> unsigned int k;
>
> data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
> @@ -209,9 +274,9 @@ static int ads1015_probe(struct i2c_client *client,
> mutex_init(&data->update_lock);
>
> /* build sysfs attribute group */
> - exported_channels = ads1015_get_exported_channels(client);
> + ads1015_get_exported_channels(client);
> for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
> - if (!(exported_channels & (1<<k)))
> + if (!data->channel_data[k].enabled)
> continue;
> err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
> if (err)
> diff --git a/include/linux/i2c/ads1015.h b/include/linux/i2c/ads1015.h
> index 8541c6a..0d9e746 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 {
> + bool enabled;
> + 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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