iio: light: ltrf216a: Add LTR-308 support

Add LiteOn LTR-308 support into LTR-F216A kernel driver.

The two devices seem to have almost identical register map, except that
the LTR-308 does not have three CLEAR_DATA registers, which are unused
by this driver. Furthermore, LTR-308 and LTR-F216A use different lux
calculation constants, 0.6 and 0.45 respectively. Both differences are
handled using chip info data.

https://optoelectronics.liteon.com/upload/download/DS86-2016-0027/LTR-308ALS_Final_%20DS_V1%201.pdf
https://optoelectronics.liteon.com/upload/download/DS86-2019-0016/LTR-F216A_Final_DS_V1.4.PDF

Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patch.msgid.link/20240708114227.18283-2-marex@denx.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/light/ltrf216a.c b/drivers/iio/light/ltrf216a.c
index 68dc48420a886aab5088f04f7a67b2a470867e8f..bc8444516689e03a90af5b274469319807994da0 100644 (file)
--- a/drivers/iio/light/ltrf216a.c
+++ b/drivers/iio/light/ltrf216a.c
@@ -68,6 +68,13 @@ static const int ltrf216a_int_time_reg[][2] = {
        {  25, 0x40 },
 };
 
+struct ltr_chip_info {
+       /* Chip contains CLEAR_DATA_0/1/2 registers at offset 0xa..0xc */
+       bool            has_clear_data;
+       /* Lux calculation multiplier for ALS data */
+       int             lux_multiplier;
+};
+
 /*
  * Window Factor is needed when the device is under Window glass
  * with coated tinted ink. This is to compensate for the light loss
@@ -79,6 +86,7 @@ static const int ltrf216a_int_time_reg[][2] = {
 struct ltrf216a_data {
        struct regmap *regmap;
        struct i2c_client *client;
+       const struct ltr_chip_info *info;
        u32 int_time;
        u16 int_time_fac;
        u8 als_gain_fac;
@@ -246,7 +254,7 @@ static int ltrf216a_get_lux(struct ltrf216a_data *data)
 
        ltrf216a_set_power_state(data, false);
 
-       lux = greendata * 45 * LTRF216A_WIN_FAC;
+       lux = greendata * data->info->lux_multiplier * LTRF216A_WIN_FAC;
 
        return lux;
 }
@@ -334,15 +342,15 @@ static const struct iio_info ltrf216a_info = {
 
 static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
 {
+       struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+       struct ltrf216a_data *data = iio_priv(indio_dev);
+
        switch (reg) {
        case LTRF216A_MAIN_CTRL:
        case LTRF216A_ALS_MEAS_RES:
        case LTRF216A_ALS_GAIN:
        case LTRF216A_PART_ID:
        case LTRF216A_MAIN_STATUS:
-       case LTRF216A_ALS_CLEAR_DATA_0:
-       case LTRF216A_ALS_CLEAR_DATA_1:
-       case LTRF216A_ALS_CLEAR_DATA_2:
        case LTRF216A_ALS_DATA_0:
        case LTRF216A_ALS_DATA_1:
        case LTRF216A_ALS_DATA_2:
@@ -355,6 +363,10 @@ static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
        case LTRF216A_ALS_THRES_LOW_1:
        case LTRF216A_ALS_THRES_LOW_2:
                return true;
+       case LTRF216A_ALS_CLEAR_DATA_0:
+       case LTRF216A_ALS_CLEAR_DATA_1:
+       case LTRF216A_ALS_CLEAR_DATA_2:
+               return data->info->has_clear_data;
        default:
                return false;
        }
@@ -382,15 +394,23 @@ static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
 
 static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
 {
+       struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+       struct ltrf216a_data *data = iio_priv(indio_dev);
+
        switch (reg) {
        case LTRF216A_MAIN_STATUS:
-       case LTRF216A_ALS_CLEAR_DATA_0:
-       case LTRF216A_ALS_CLEAR_DATA_1:
-       case LTRF216A_ALS_CLEAR_DATA_2:
        case LTRF216A_ALS_DATA_0:
        case LTRF216A_ALS_DATA_1:
        case LTRF216A_ALS_DATA_2:
                return true;
+       /*
+        * If these registers are not present on a chip (like LTR-308),
+        * the missing registers are not considered volatile.
+        */
+       case LTRF216A_ALS_CLEAR_DATA_0:
+       case LTRF216A_ALS_CLEAR_DATA_1:
+       case LTRF216A_ALS_CLEAR_DATA_2:
+               return data->info->has_clear_data;
        default:
                return false;
        }
@@ -433,6 +453,7 @@ static int ltrf216a_probe(struct i2c_client *client)
 
        i2c_set_clientdata(client, indio_dev);
        data->client = client;
+       data->info = i2c_get_match_data(client);
 
        mutex_init(&data->lock);
 
@@ -520,15 +541,27 @@ cache_only:
 static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
                                 ltrf216a_runtime_resume, NULL);
 
+static const struct ltr_chip_info ltr308_chip_info = {
+       .has_clear_data         = false,
+       .lux_multiplier         = 60,
+};
+
+static const struct ltr_chip_info ltrf216a_chip_info = {
+       .has_clear_data         = true,
+       .lux_multiplier         = 45,
+};
+
 static const struct i2c_device_id ltrf216a_id[] = {
-       { "ltrf216a" },
+       { "ltr308", .driver_data = (kernel_ulong_t)&ltr308_chip_info },
+       { "ltrf216a", .driver_data = (kernel_ulong_t)&ltrf216a_chip_info },
        {}
 };
 MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
 
 static const struct of_device_id ltrf216a_of_match[] = {
-       { .compatible = "liteon,ltrf216a" },
-       { .compatible = "ltr,ltrf216a" },
+       { .compatible = "liteon,ltr308", .data = &ltr308_chip_info },
+       { .compatible = "liteon,ltrf216a", .data = &ltrf216a_chip_info },
+       { .compatible = "ltr,ltrf216a", .data = &ltrf216a_chip_info },
        {}
 };
 MODULE_DEVICE_TABLE(of, ltrf216a_of_match);