[lm-sensors] [PATCH] hwmon: (ads1015) Make gain and datarate configurable
Guenter Roeck
guenter.roeck at ericsson.com
Fri Mar 11 06:04:10 EST 2011
Hi Dirk,
On Wed, 2011-03-09 at 08:52 -0500, Dirk Eibach wrote:
> 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
> +
Just a thought ... if you specify the data rate (and possibly pga) this
way, you'll have to redefine its meaning for ads1115. If you just define
it as "samples per second" and then calculate the index from it in the
code (eg as closest match), you'd be done.
> +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},
Should have a blank between 5 and } for consistency.
> + }
> };
>
> -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;
> + }
Can channel be < 0 ?
> +
> + 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);
> + }
> + }
Can pga be < 0 ? Also, no action if pga is bad ?
> +
> + 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);
> + }
No action if data_rate is bad ? And can it be < 0 ?
> +
> + 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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