media: video-i2c: add hwmon support for amg88xx

AMG88xx has an on-board thermistor which is used for more accurate
processing of its temperature readings from the 8x8 thermopile array

Cc: linux-hwmon@vger.kernel.org
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 5ee7a09001a7decae5bae60d23e59c63f571df9d..439f6be08b956c81cda64a690e811169c3ab4c6a 100644 (file)
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -1033,6 +1033,7 @@ config VIDEO_I2C
        tristate "I2C transport video support"
        depends on VIDEO_V4L2 && I2C
        select VIDEOBUF2_VMALLOC
+       imply HWMON
        ---help---
          Enable the I2C transport video support which supports the
          following:

diff --git a/drivers/media/i2c/video-i2c.c b/drivers/media/i2c/video-i2c.c
index 0b347cc19aa538ae0ceb8dbd47fa318b271c0ea0..7dc9338502e5ccd308fbaa850853d1b99961176b 100644 (file)
--- a/drivers/media/i2c/video-i2c.c
+++ b/drivers/media/i2c/video-i2c.c
@@ -10,6 +10,7 @@
 
 #include <linux/delay.h>
 #include <linux/freezer.h>
+#include <linux/hwmon.h>
 #include <linux/kthread.h>
 #include <linux/i2c.h>
 #include <linux/list.h>
@@ -77,6 +78,9 @@ struct video_i2c_chip {
 
        /* xfer function */
        int (*xfer)(struct video_i2c_data *data, char *buf);
+
+       /* hwmon init function */
+       int (*hwmon_init)(struct video_i2c_data *data);
 };
 
 static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
@@ -101,6 +105,74 @@ static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
        return (ret == 2) ? 0 : -EIO;
 }
 
+#if IS_ENABLED(CONFIG_HWMON)
+
+static const u32 amg88xx_temp_config[] = {
+       HWMON_T_INPUT,
+       0
+};
+
+static const struct hwmon_channel_info amg88xx_temp = {
+       .type = hwmon_temp,
+       .config = amg88xx_temp_config,
+};
+
+static const struct hwmon_channel_info *amg88xx_info[] = {
+       &amg88xx_temp,
+       NULL
+};
+
+static umode_t amg88xx_is_visible(const void *drvdata,
+                                 enum hwmon_sensor_types type,
+                                 u32 attr, int channel)
+{
+       return 0444;
+}
+
+static int amg88xx_read(struct device *dev, enum hwmon_sensor_types type,
+                       u32 attr, int channel, long *val)
+{
+       struct video_i2c_data *data = dev_get_drvdata(dev);
+       struct i2c_client *client = data->client;
+       int tmp = i2c_smbus_read_word_data(client, 0x0e);
+
+       if (tmp < 0)
+               return tmp;
+
+       /*
+        * Check for sign bit, this isn't a two's complement value but an
+        * absolute temperature that needs to be inverted in the case of being
+        * negative.
+        */
+       if (tmp & BIT(11))
+               tmp = -(tmp & 0x7ff);
+
+       *val = (tmp * 625) / 10;
+
+       return 0;
+}
+
+static const struct hwmon_ops amg88xx_hwmon_ops = {
+       .is_visible = amg88xx_is_visible,
+       .read = amg88xx_read,
+};
+
+static const struct hwmon_chip_info amg88xx_chip_info = {
+       .ops = &amg88xx_hwmon_ops,
+       .info = amg88xx_info,
+};
+
+static int amg88xx_hwmon_init(struct video_i2c_data *data)
+{
+       void *hwmon = devm_hwmon_device_register_with_info(&data->client->dev,
+                               "amg88xx", data, &amg88xx_chip_info, NULL);
+
+       return PTR_ERR(hwmon);
+}
+#else
+#define        amg88xx_hwmon_init      NULL
+#endif
+
 #define AMG88XX                0
 
 static const struct video_i2c_chip video_i2c_chip[] = {
@@ -111,6 +183,7 @@ static const struct video_i2c_chip video_i2c_chip[] = {
                .buffer_size    = 128,
                .bpp            = 16,
                .xfer           = &amg88xx_xfer,
+               .hwmon_init     = amg88xx_hwmon_init,
        },
 };
 
@@ -505,6 +578,14 @@ static int video_i2c_probe(struct i2c_client *client,
        video_set_drvdata(&data->vdev, data);
        i2c_set_clientdata(client, data);
 
+       if (data->chip->hwmon_init) {
+               ret = data->chip->hwmon_init(data);
+               if (ret < 0) {
+                       dev_warn(&client->dev,
+                                "failed to register hwmon device\n");
+               }
+       }
+
        ret = video_register_device(&data->vdev, VFL_TYPE_GRABBER, -1);
        if (ret < 0)
                goto error_unregister_device;