iio: ltr501: Add support for ltr559 chip

This device is register compatible with LTR501, with a minor difference for
ALS control register as showed below:

ALS Control register for LTR501:

    7      6      5      4      3      2      1      0
+------+------+------+------+------+------+------+------+
|                           |      |      |             |
|        Reserved           | Gain |  SW  |    ALS Mode |
|                           |      | Reset|             |
+------+------+------+------+------+------+------+------+

ALS Control register for LTR559:

    7      6      5      4      3      2      1      0
+------+------+------+------+------+------+------+------+
|                    |                    |      |      |
|     Reserved       |        Gain        |  SW  | ALS  |
|                    |                    | Reset| Mode |
+------+------+------+------+------+------+------+------+

We handle this difference by introducing ltr501_chip_info.

Datasheet for LTR559 is at:
http://optoelectronics.liteon.com/upload/download/DS86-2013-0003/S_110_LTR-559ALS-01_DS_V1.pdf

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

2 files changed, 186 insertions, 35 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 01a1a16ab7be..16a0ba11ab6e 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -169,7 +169,8 @@ config LTR501
         select IIO_TRIGGERED_BUFFER
         help
          If you say yes here you get support for the Lite-On LTR-501ALS-01
-         ambient light and proximity sensor.
+         ambient light and proximity sensor. This driver also supports LTR-559
+         ALS/PS sensor.
 
          This driver can also be built as a module.  If so, the module
          will be called ltr501.
diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index 0162e8652118..92da5146bc1c 100644
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -88,9 +88,63 @@ struct ltr501_samp_table {
         int time_val; /* repetition rate in micro seconds */
 };
 
+#define LTR501_RESERVED_GAIN -1
+
+enum {
+        ltr501 = 0,
+        ltr559,
+};
+
+struct ltr501_gain {
+        int scale;
+        int uscale;
+};
+
+static struct ltr501_gain ltr501_als_gain_tbl[] = {
+        {1, 0},
+        {0, 5000},
+};
+
+static struct ltr501_gain ltr559_als_gain_tbl[] = {
+        {1, 0},
+        {0, 500000},
+        {0, 250000},
+        {0, 125000},
+        {LTR501_RESERVED_GAIN, LTR501_RESERVED_GAIN},
+        {LTR501_RESERVED_GAIN, LTR501_RESERVED_GAIN},
+        {0, 20000},
+        {0, 10000},
+};
+
+static struct ltr501_gain ltr501_ps_gain_tbl[] = {
+        {1, 0},
+        {0, 250000},
+        {0, 125000},
+        {0, 62500},
+};
+
+static struct ltr501_gain ltr559_ps_gain_tbl[] = {
+        {0, 62500}, /* x16 gain */
+        {0, 31250}, /* x32 gain */
+        {0, 15625}, /* bits X1 are for x64 gain */
+        {0, 15624},
+};
+
+struct ltr501_chip_info {
+        u8 partid;
+        struct ltr501_gain *als_gain;
+        int als_gain_tbl_size;
+        struct ltr501_gain *ps_gain;
+        int ps_gain_tbl_size;
+        u8 als_mode_active;
+        u8 als_gain_mask;
+        u8 als_gain_shift;
+};
+
 struct ltr501_data {
         struct i2c_client *client;
         struct mutex lock_als, lock_ps;
+        struct ltr501_chip_info *chip_info;
         u8 als_contr, ps_contr;
         int als_period, ps_period; /* period in micro seconds */
         struct regmap *regmap;
@@ -516,10 +570,6 @@ static const struct iio_chan_spec ltr501_channels[] = {
         IIO_CHAN_SOFT_TIMESTAMP(3),
 };
 
-static const int ltr501_ps_gain[4][2] = {
-        {1, 0}, {0, 250000}, {0, 125000}, {0, 62500}
-};
-
 static int ltr501_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
@@ -557,19 +607,16 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
         case IIO_CHAN_INFO_SCALE:
                 switch (chan->type) {
                 case IIO_INTENSITY:
-                        if (data->als_contr & LTR501_CONTR_ALS_GAIN_MASK) {
-                                *val = 0;
-                                *val2 = 5000;
-                                return IIO_VAL_INT_PLUS_MICRO;
-                        }
-                        *val = 1;
-                        *val2 = 0;
-                        return IIO_VAL_INT;
+                        i = (data->als_contr & data->chip_info->als_gain_mask)
+                             >> data->chip_info->als_gain_shift;
+                        *val = data->chip_info->als_gain[i].scale;
+                        *val2 = data->chip_info->als_gain[i].uscale;
+                        return IIO_VAL_INT_PLUS_MICRO;
                 case IIO_PROXIMITY:
                         i = (data->ps_contr & LTR501_CONTR_PS_GAIN_MASK) >>
                                 LTR501_CONTR_PS_GAIN_SHIFT;
-                        *val = ltr501_ps_gain[i][0];
-                        *val2 = ltr501_ps_gain[i][1];
+                        *val = data->chip_info->ps_gain[i].scale;
+                        *val2 = data->chip_info->ps_gain[i].uscale;
                         return IIO_VAL_INT_PLUS_MICRO;
                 default:
                         return -EINVAL;
@@ -594,12 +641,13 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
         return -EINVAL;
 }
 
-static int ltr501_get_ps_gain_index(int val, int val2)
+static int ltr501_get_gain_index(struct ltr501_gain *gain, int size,
+                                 int val, int val2)
 {
         int i;
 
-        for (i = 0; i < ARRAY_SIZE(ltr501_ps_gain); i++)
-                if (val == ltr501_ps_gain[i][0] && val2 == ltr501_ps_gain[i][1])
+        for (i = 0; i < size; i++)
+                if (val == gain[i].scale && val2 == gain[i].uscale)
                         return i;
 
         return -1;
@@ -611,6 +659,7 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
 {
         struct ltr501_data *data = iio_priv(indio_dev);
         int i, ret, freq_val, freq_val2;
+        struct ltr501_chip_info *info = data->chip_info;
 
         if (iio_buffer_enabled(indio_dev))
                 return -EBUSY;
@@ -619,17 +668,21 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
         case IIO_CHAN_INFO_SCALE:
                 switch (chan->type) {
                 case IIO_INTENSITY:
-                        if (val == 0 && val2 == 5000)
-                                data->als_contr |= LTR501_CONTR_ALS_GAIN_MASK;
-                        else if (val == 1 && val2 == 0)
-                                data->als_contr &= ~LTR501_CONTR_ALS_GAIN_MASK;
-                        else
+                        i = ltr501_get_gain_index(info->als_gain,
+                                                  info->als_gain_tbl_size,
+                                                  val, val2);
+                        if (i < 0)
                                 return -EINVAL;
 
+                        data->als_contr &= ~info->als_gain_mask;
+                        data->als_contr |= i << info->als_gain_shift;
+
                         return regmap_write(data->regmap, LTR501_ALS_CONTR,
                                             data->als_contr);
                 case IIO_PROXIMITY:
-                        i = ltr501_get_ps_gain_index(val, val2);
+                        i = ltr501_get_gain_index(info->ps_gain,
+                                                  info->ps_gain_tbl_size,
+                                                  val, val2);
                         if (i < 0)
                                 return -EINVAL;
                         data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
@@ -927,14 +980,61 @@ static int ltr501_write_event_config(struct iio_dev *indio_dev,
         return -EINVAL;
 }
 
-static IIO_CONST_ATTR(in_proximity_scale_available, "1 0.25 0.125 0.0625");
-static IIO_CONST_ATTR(in_intensity_scale_available, "1 0.005");
+static ssize_t ltr501_show_proximity_scale_avail(struct device *dev,
+                                                 struct device_attribute *attr,
+                                                 char *buf)
+{
+        struct ltr501_data *data = iio_priv(dev_to_iio_dev(dev));
+        struct ltr501_chip_info *info = data->chip_info;
+        ssize_t len = 0;
+        int i;
+
+        for (i = 0; i < info->ps_gain_tbl_size; i++) {
+                if (info->ps_gain[i].scale == LTR501_RESERVED_GAIN)
+                        continue;
+                len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ",
+                                 info->ps_gain[i].scale,
+                                 info->ps_gain[i].uscale);
+        }
+
+        buf[len - 1] = '\n';
+
+        return len;
+}
+
+static ssize_t ltr501_show_intensity_scale_avail(struct device *dev,
+                                                 struct device_attribute *attr,
+                                                 char *buf)
+{
+        struct ltr501_data *data = iio_priv(dev_to_iio_dev(dev));
+        struct ltr501_chip_info *info = data->chip_info;
+        ssize_t len = 0;
+        int i;
+
+        for (i = 0; i < info->als_gain_tbl_size; i++) {
+                if (info->als_gain[i].scale == LTR501_RESERVED_GAIN)
+                        continue;
+                len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06d ",
+                                 info->als_gain[i].scale,
+                                 info->als_gain[i].uscale);
+        }
+
+        buf[len - 1] = '\n';
+
+        return len;
+}
+
 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.05 0.1 0.2 0.4");
 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");
 
+static IIO_DEVICE_ATTR(in_proximity_scale_available, S_IRUGO,
+                       ltr501_show_proximity_scale_avail, NULL, 0);
+static IIO_DEVICE_ATTR(in_intensity_scale_available, S_IRUGO,
+                       ltr501_show_intensity_scale_avail, NULL, 0);
+
 static struct attribute *ltr501_attributes[] = {
-        &iio_const_attr_in_proximity_scale_available.dev_attr.attr,
-        &iio_const_attr_in_intensity_scale_available.dev_attr.attr,
+        &iio_dev_attr_in_proximity_scale_available.dev_attr.attr,
+        &iio_dev_attr_in_intensity_scale_available.dev_attr.attr,
         &iio_const_attr_integration_time_available.dev_attr.attr,
         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
         NULL
@@ -962,6 +1062,29 @@ static const struct iio_info ltr501_info = {
         .driver_module = THIS_MODULE,
 };
 
+static struct ltr501_chip_info ltr501_chip_info_tbl[] = {
+        [ltr501] = {
+                .partid = 0x08,
+                .als_gain = ltr501_als_gain_tbl,
+                .als_gain_tbl_size = ARRAY_SIZE(ltr501_als_gain_tbl),
+                .ps_gain = ltr501_ps_gain_tbl,
+                .ps_gain_tbl_size = ARRAY_SIZE(ltr501_ps_gain_tbl),
+                .als_mode_active = BIT(0) | BIT(1),
+                .als_gain_mask = BIT(3),
+                .als_gain_shift = 3,
+        },
+        [ltr559] = {
+                .partid = 0x09,
+                .als_gain = ltr559_als_gain_tbl,
+                .als_gain_tbl_size = ARRAY_SIZE(ltr559_als_gain_tbl),
+                .ps_gain = ltr559_ps_gain_tbl,
+                .ps_gain_tbl_size = ARRAY_SIZE(ltr559_ps_gain_tbl),
+                .als_mode_active = BIT(1),
+                .als_gain_mask = BIT(2) | BIT(3) | BIT(4),
+                .als_gain_shift = 2,
+        },
+};
+
 static int ltr501_write_contr(struct ltr501_data *data, u8 als_val, u8 ps_val)
 {
         int ret;
@@ -1062,7 +1185,7 @@ static int ltr501_init(struct ltr501_data *data)
         if (ret < 0)
                 return ret;
 
-        data->als_contr = status | LTR501_CONTR_ACTIVE;
+        data->als_contr = ret | data->chip_info->als_mode_active;
 
         ret = regmap_read(data->regmap, LTR501_PS_CONTR, &status);
         if (ret < 0)
@@ -1105,17 +1228,30 @@ static struct regmap_config ltr501_regmap_config = {
 
 static int ltr501_powerdown(struct ltr501_data *data)
 {
-        return ltr501_write_contr(data, data->als_contr & ~LTR501_CONTR_ACTIVE,
+        return ltr501_write_contr(data, data->als_contr &
+                                  ~data->chip_info->als_mode_active,
                                   data->ps_contr & ~LTR501_CONTR_ACTIVE);
 }
 
+static const char *ltr501_match_acpi_device(struct device *dev, int *chip_idx)
+{
+        const struct acpi_device_id *id;
+
+        id = acpi_match_device(dev->driver->acpi_match_table, dev);
+        if (!id)
+                return NULL;
+        *chip_idx = id->driver_data;
+        return dev_name(dev);
+}
+
 static int ltr501_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
         struct ltr501_data *data;
         struct iio_dev *indio_dev;
         struct regmap *regmap;
-        int ret, partid;
+        int ret, partid, chip_idx = 0;
+        const char *name = NULL;
 
         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
         if (!indio_dev)
@@ -1186,13 +1322,25 @@ static int ltr501_probe(struct i2c_client *client,
         ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
         if (ret < 0)
                 return ret;
-        if ((partid >> 4) != 0x8)
+
+        if (id) {
+                name = id->name;
+                chip_idx = id->driver_data;
+        } else  if (ACPI_HANDLE(&client->dev)) {
+                name = ltr501_match_acpi_device(&client->dev, &chip_idx);
+        } else {
+                return -ENODEV;
+        }
+
+        data->chip_info = &ltr501_chip_info_tbl[chip_idx];
+
+        if ((partid >> 4) != data->chip_info->partid)
                 return -ENODEV;
 
         indio_dev->dev.parent = &client->dev;
         indio_dev->channels = ltr501_channels;
         indio_dev->num_channels = ARRAY_SIZE(ltr501_channels);
-        indio_dev->name = LTR501_DRV_NAME;
+        indio_dev->name = name;
         indio_dev->modes = INDIO_DIRECT_MODE;
 
         ret = ltr501_init(data);
@@ -1266,13 +1414,15 @@ static int ltr501_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(ltr501_pm_ops, ltr501_suspend, ltr501_resume);
 
 static const struct acpi_device_id ltr_acpi_match[] = {
-        {"LTER0501", 0},
+        {"LTER0501", ltr501},
+        {"LTER0559", ltr559},
         { },
 };
 MODULE_DEVICE_TABLE(acpi, ltr_acpi_match);
 
 static const struct i2c_device_id ltr501_id[] = {
-        { "ltr501", 0 },
+        { "ltr501", ltr501},
+        { "ltr559", ltr559},
         { }
 };
 MODULE_DEVICE_TABLE(i2c, ltr501_id);