iio: light: Add support for UPISEMI uS5182d als and proximity sensor

Add support for UPISEMI us5182d als and proximity sensor.
Supports raw readings.
Data sheet for this device can be found here:
http://www.upi-semi.com/temp/uS5182D-DS-P0103-temp.pdf

Signed-off-by: Adriana Reus <adriana.reus@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 518 insertions, 0 deletions

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 19b9a173fe61..cfd3df8416bb 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -300,6 +300,16 @@ config TSL4531
          To compile this driver as a module, choose M here: the
          module will be called tsl4531.
 
+config US5182D
+        tristate "UPISEMI light and proximity sensor"
+        depends on I2C
+        help
+         If you say yes here you get support for the UPISEMI US5182D
+         ambient light and proximity sensor.
+
+         This driver can also be built as a module.  If so, the module
+         will be called us5182d.
+
 config VCNL4000
         tristate "VCNL4000 combined ALS and proximity sensor"
         depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 7b2244550747..b2c31053db0c 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -28,4 +28,5 @@ obj-$(CONFIG_STK3310)          += stk3310.o
 obj-$(CONFIG_TCS3414)           += tcs3414.o
 obj-$(CONFIG_TCS3472)           += tcs3472.o
 obj-$(CONFIG_TSL4531)           += tsl4531.o
+obj-$(CONFIG_US5182D)           += us5182d.o
 obj-$(CONFIG_VCNL4000)          += vcnl4000.o
diff --git a/drivers/iio/light/us5182d.c b/drivers/iio/light/us5182d.c
new file mode 100644
index 000000000000..49dab3cb3e23
--- /dev/null
+++ b/drivers/iio/light/us5182d.c
@@ -0,0 +1,507 @@
+/*
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * Driver for UPISEMI us5182d Proximity and Ambient Light Sensor.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * To do: Interrupt support.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/mutex.h>
+
+#define US5182D_REG_CFG0                                0x00
+#define US5182D_CFG0_ONESHOT_EN                         BIT(6)
+#define US5182D_CFG0_SHUTDOWN_EN                        BIT(7)
+#define US5182D_CFG0_WORD_ENABLE                        BIT(0)
+
+#define US5182D_REG_CFG1                                0x01
+#define US5182D_CFG1_ALS_RES16                          BIT(4)
+#define US5182D_CFG1_AGAIN_DEFAULT                      0x00
+
+#define US5182D_REG_CFG2                                0x02
+#define US5182D_CFG2_PX_RES16                           BIT(4)
+#define US5182D_CFG2_PXGAIN_DEFAULT                     BIT(2)
+
+#define US5182D_REG_CFG3                                0x03
+#define US5182D_CFG3_LED_CURRENT100                     (BIT(4) | BIT(5))
+
+#define US5182D_REG_CFG4                                0x10
+
+/*
+ * Registers for tuning the auto dark current cancelling feature.
+ * DARK_TH(reg 0x27,0x28) - threshold (counts) for auto dark cancelling.
+ * when ALS  > DARK_TH --> ALS_Code = ALS - Upper(0x2A) * Dark
+ * when ALS < DARK_TH --> ALS_Code = ALS - Lower(0x29) * Dark
+ */
+#define US5182D_REG_UDARK_TH                    0x27
+#define US5182D_REG_DARK_AUTO_EN                0x2b
+#define US5182D_REG_AUTO_LDARK_GAIN             0x29
+#define US5182D_REG_AUTO_HDARK_GAIN             0x2a
+
+#define US5182D_OPMODE_ALS                      0x01
+#define US5182D_OPMODE_PX                       0x02
+#define US5182D_OPMODE_SHIFT                    4
+
+#define US5182D_REG_DARK_AUTO_EN_DEFAULT        0x80
+#define US5182D_REG_AUTO_LDARK_GAIN_DEFAULT     0x16
+#define US5182D_REG_AUTO_HDARK_GAIN_DEFAULT     0x00
+
+#define US5182D_REG_ADL                         0x0c
+#define US5182D_REG_PDL                         0x0e
+
+#define US5182D_REG_MODE_STORE                  0x21
+#define US5182D_STORE_MODE                      0x01
+
+#define US5182D_REG_CHIPID                      0xb2
+
+#define US5182D_OPMODE_MASK                     GENMASK(5, 4)
+#define US5182D_AGAIN_MASK                      0x07
+#define US5182D_RESET_CHIP                      0x01
+
+#define US5182D_CHIPID                          0x26
+#define US5182D_DRV_NAME                        "us5182d"
+
+#define US5182D_GA_RESOLUTION                   1000
+
+#define US5182D_READ_BYTE                       1
+#define US5182D_READ_WORD                       2
+#define US5182D_OPSTORE_SLEEP_TIME              20 /* ms */
+
+/* Available ranges: [12354, 7065, 3998, 2202, 1285, 498, 256, 138] lux */
+static const int us5182d_scales[] = {188500, 107800, 61000, 33600, 19600, 7600,
+                                     3900, 2100};
+
+/*
+ * Experimental thresholds that work with US5182D sensor on evaluation board
+ * roughly between 12-32 lux
+ */
+static u16 us5182d_dark_ths_vals[] = {170, 200, 512, 512, 800, 2000, 4000,
+                                      8000};
+
+enum mode {
+        US5182D_ALS_PX,
+        US5182D_ALS_ONLY,
+        US5182D_PX_ONLY
+};
+
+struct us5182d_data {
+        struct i2c_client *client;
+        struct mutex lock;
+
+        /* Glass attenuation factor */
+        u32 ga;
+
+        /* Dark gain tuning */
+        u8 lower_dark_gain;
+        u8 upper_dark_gain;
+        u16 *us5182d_dark_ths;
+
+        u8 opmode;
+};
+
+static IIO_CONST_ATTR(in_illuminance_scale_available,
+                      "0.0021 0.0039 0.0076 0.0196 0.0336 0.061 0.1078 0.1885");
+
+static struct attribute *us5182d_attrs[] = {
+        &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
+        NULL
+};
+
+static const struct attribute_group us5182d_attr_group = {
+        .attrs = us5182d_attrs,
+};
+
+static const struct {
+        u8 reg;
+        u8 val;
+} us5182d_regvals[] = {
+        {US5182D_REG_CFG0, (US5182D_CFG0_SHUTDOWN_EN |
+                            US5182D_CFG0_WORD_ENABLE)},
+        {US5182D_REG_CFG1, US5182D_CFG1_ALS_RES16},
+        {US5182D_REG_CFG2, (US5182D_CFG2_PX_RES16 |
+                            US5182D_CFG2_PXGAIN_DEFAULT)},
+        {US5182D_REG_CFG3, US5182D_CFG3_LED_CURRENT100},
+        {US5182D_REG_MODE_STORE, US5182D_STORE_MODE},
+        {US5182D_REG_CFG4, 0x00},
+};
+
+static const struct iio_chan_spec us5182d_channels[] = {
+        {
+                .type = IIO_LIGHT,
+                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+                                      BIT(IIO_CHAN_INFO_SCALE),
+        },
+        {
+                .type = IIO_PROXIMITY,
+                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+        }
+};
+
+static int us5182d_get_als(struct us5182d_data *data)
+{
+        int ret;
+        unsigned long result;
+
+        ret = i2c_smbus_read_word_data(data->client,
+                                       US5182D_REG_ADL);
+        if (ret < 0)
+                return ret;
+
+        result = ret * data->ga / US5182D_GA_RESOLUTION;
+        if (result > 0xffff)
+                result = 0xffff;
+
+        return result;
+}
+
+static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
+{
+        int ret;
+
+        ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CFG0);
+        if (ret < 0)
+                return ret;
+
+        /*
+         * In oneshot mode the chip will power itself down after taking the
+         * required measurement.
+         */
+        ret = ret | US5182D_CFG0_ONESHOT_EN;
+
+        /* update mode */
+        ret = ret & ~US5182D_OPMODE_MASK;
+        ret = ret | (mode << US5182D_OPMODE_SHIFT);
+
+        /*
+         * After updating the operating mode, the chip requires that
+         * the operation is stored, by writing 1 in the STORE_MODE
+         * register (auto-clearing).
+         */
+        ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG0, ret);
+        if (ret < 0)
+                return ret;
+
+        if (mode == data->opmode)
+                return 0;
+
+        ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_MODE_STORE,
+                                        US5182D_STORE_MODE);
+        if (ret < 0)
+                return ret;
+
+        data->opmode = mode;
+        msleep(US5182D_OPSTORE_SLEEP_TIME);
+
+        return 0;
+}
+
+static int us5182d_read_raw(struct iio_dev *indio_dev,
+                            struct iio_chan_spec const *chan, int *val,
+                            int *val2, long mask)
+{
+        struct us5182d_data *data = iio_priv(indio_dev);
+        int ret;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                switch (chan->type) {
+                case IIO_LIGHT:
+                        mutex_lock(&data->lock);
+                        ret = us5182d_set_opmode(data, US5182D_OPMODE_ALS);
+                        if (ret < 0)
+                                goto out_err;
+
+                        ret = us5182d_get_als(data);
+                        if (ret < 0)
+                                goto out_err;
+                        mutex_unlock(&data->lock);
+                        *val = ret;
+                        return IIO_VAL_INT;
+                case IIO_PROXIMITY:
+                        mutex_lock(&data->lock);
+                        ret = us5182d_set_opmode(data, US5182D_OPMODE_PX);
+                        if (ret < 0)
+                                goto out_err;
+
+                        ret = i2c_smbus_read_word_data(data->client,
+                                                       US5182D_REG_PDL);
+                        if (ret < 0)
+                                goto out_err;
+                        mutex_unlock(&data->lock);
+                        *val = ret;
+                        return  IIO_VAL_INT;
+                default:
+                        return -EINVAL;
+                }
+
+        case IIO_CHAN_INFO_SCALE:
+                ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CFG1);
+                if (ret < 0)
+                        return ret;
+
+                *val = 0;
+                *val2 = us5182d_scales[ret & US5182D_AGAIN_MASK];
+
+                return IIO_VAL_INT_PLUS_MICRO;
+        default:
+                return -EINVAL;
+        }
+
+        return -EINVAL;
+out_err:
+        mutex_unlock(&data->lock);
+        return ret;
+}
+
+/**
+ * us5182d_update_dark_th - update Darh_Th registers
+ * @data        us5182d_data structure
+ * @index       index in us5182d_dark_ths array to use for the updated value
+ *
+ * Function needs to be called with a lock held because it needs two i2c write
+ * byte operations as these registers (0x27 0x28) don't work in word mode
+ * accessing.
+ */
+static int us5182d_update_dark_th(struct us5182d_data *data, int index)
+{
+        __be16 dark_th = cpu_to_be16(data->us5182d_dark_ths[index]);
+        int ret;
+
+        ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_UDARK_TH,
+                                        ((u8 *)&dark_th)[0]);
+        if (ret < 0)
+                return ret;
+
+        return i2c_smbus_write_byte_data(data->client, US5182D_REG_UDARK_TH + 1,
+                                        ((u8 *)&dark_th)[1]);
+}
+
+/**
+ * us5182d_apply_scale - update the ALS scale
+ * @data        us5182d_data structure
+ * @index       index in us5182d_scales array to use for the updated value
+ *
+ * Function needs to be called with a lock held as we're having more than one
+ * i2c operation.
+ */
+static int us5182d_apply_scale(struct us5182d_data *data, int index)
+{
+        int ret;
+
+        ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CFG1);
+        if (ret < 0)
+                return ret;
+
+        ret = ret & (~US5182D_AGAIN_MASK);
+        ret |= index;
+
+        ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG1, ret);
+        if (ret < 0)
+                return ret;
+
+        return us5182d_update_dark_th(data, index);
+}
+
+static int us5182d_write_raw(struct iio_dev *indio_dev,
+                             struct iio_chan_spec const *chan, int val,
+                             int val2, long mask)
+{
+        struct us5182d_data *data = iio_priv(indio_dev);
+        int ret, i;
+
+        switch (mask) {
+        case IIO_CHAN_INFO_SCALE:
+                if (val != 0)
+                        return -EINVAL;
+                for (i = 0; i < ARRAY_SIZE(us5182d_scales); i++)
+                        if (val2 == us5182d_scales[i]) {
+                                mutex_lock(&data->lock);
+                                ret = us5182d_apply_scale(data, i);
+                                mutex_unlock(&data->lock);
+                                return ret;
+                        }
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return -EINVAL;
+}
+
+static const struct iio_info us5182d_info = {
+        .driver_module  = THIS_MODULE,
+        .read_raw = us5182d_read_raw,
+        .write_raw = us5182d_write_raw,
+        .attrs = &us5182d_attr_group,
+};
+
+static int us5182d_reset(struct iio_dev *indio_dev)
+{
+        struct us5182d_data *data = iio_priv(indio_dev);
+
+        return i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG3,
+                                         US5182D_RESET_CHIP);
+}
+
+static int us5182d_init(struct iio_dev *indio_dev)
+{
+        struct us5182d_data *data = iio_priv(indio_dev);
+        int i, ret;
+
+        ret = us5182d_reset(indio_dev);
+        if (ret < 0)
+                return ret;
+
+        data->opmode = 0;
+        for (i = 0; i < ARRAY_SIZE(us5182d_regvals); i++) {
+                ret = i2c_smbus_write_byte_data(data->client,
+                                                us5182d_regvals[i].reg,
+                                                us5182d_regvals[i].val);
+                if (ret < 0)
+                        return ret;
+        }
+
+        return 0;
+}
+
+static void us5182d_get_platform_data(struct iio_dev *indio_dev)
+{
+        struct us5182d_data *data = iio_priv(indio_dev);
+
+        if (device_property_read_u32(&data->client->dev, "upisemi,glass-coef",
+                                     &data->ga))
+                data->ga = US5182D_GA_RESOLUTION;
+        if (device_property_read_u16_array(&data->client->dev,
+                                           "upisemi,dark-ths",
+                                           data->us5182d_dark_ths,
+                                           ARRAY_SIZE(us5182d_dark_ths_vals)))
+                data->us5182d_dark_ths = us5182d_dark_ths_vals;
+        if (device_property_read_u8(&data->client->dev,
+                                    "upisemi,upper-dark-gain",
+                                    &data->upper_dark_gain))
+                data->upper_dark_gain = US5182D_REG_AUTO_HDARK_GAIN_DEFAULT;
+        if (device_property_read_u8(&data->client->dev,
+                                    "upisemi,lower-dark-gain",
+                                    &data->lower_dark_gain))
+                data->lower_dark_gain = US5182D_REG_AUTO_LDARK_GAIN_DEFAULT;
+}
+
+static int  us5182d_dark_gain_config(struct iio_dev *indio_dev)
+{
+        struct us5182d_data *data = iio_priv(indio_dev);
+        int ret;
+
+        ret = us5182d_update_dark_th(data, US5182D_CFG1_AGAIN_DEFAULT);
+        if (ret < 0)
+                return ret;
+
+        ret = i2c_smbus_write_byte_data(data->client,
+                                        US5182D_REG_AUTO_LDARK_GAIN,
+                                        data->lower_dark_gain);
+        if (ret < 0)
+                return ret;
+
+        ret = i2c_smbus_write_byte_data(data->client,
+                                        US5182D_REG_AUTO_HDARK_GAIN,
+                                        data->upper_dark_gain);
+        if (ret < 0)
+                return ret;
+
+        return i2c_smbus_write_byte_data(data->client, US5182D_REG_DARK_AUTO_EN,
+                                         US5182D_REG_DARK_AUTO_EN_DEFAULT);
+}
+
+static int us5182d_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct us5182d_data *data;
+        struct iio_dev *indio_dev;
+        int ret;
+
+        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+        if (!indio_dev)
+                return -ENOMEM;
+
+        data = iio_priv(indio_dev);
+        i2c_set_clientdata(client, indio_dev);
+        data->client = client;
+
+        mutex_init(&data->lock);
+
+        indio_dev->dev.parent = &client->dev;
+        indio_dev->info = &us5182d_info;
+        indio_dev->name = US5182D_DRV_NAME;
+        indio_dev->channels = us5182d_channels;
+        indio_dev->num_channels = ARRAY_SIZE(us5182d_channels);
+        indio_dev->modes = INDIO_DIRECT_MODE;
+
+        ret = i2c_smbus_read_byte_data(data->client, US5182D_REG_CHIPID);
+        if (ret != US5182D_CHIPID) {
+                dev_err(&data->client->dev,
+                        "Failed to detect US5182 light chip\n");
+                return (ret < 0) ? ret : -ENODEV;
+        }
+
+        us5182d_get_platform_data(indio_dev);
+        ret = us5182d_init(indio_dev);
+        if (ret < 0)
+                return ret;
+
+        ret = us5182d_dark_gain_config(indio_dev);
+        if (ret < 0)
+                return ret;
+
+        return iio_device_register(indio_dev);
+}
+
+static int us5182d_remove(struct i2c_client *client)
+{
+        iio_device_unregister(i2c_get_clientdata(client));
+        return i2c_smbus_write_byte_data(client, US5182D_REG_CFG0,
+                                         US5182D_CFG0_SHUTDOWN_EN);
+}
+
+static const struct acpi_device_id us5182d_acpi_match[] = {
+        { "USD5182", 0},
+        {}
+};
+
+MODULE_DEVICE_TABLE(acpi, us5182d_acpi_match);
+
+static const struct i2c_device_id us5182d_id[] = {
+                {"usd5182", 0},
+                {}
+};
+
+MODULE_DEVICE_TABLE(i2c, us5182d_id);
+
+static struct i2c_driver us5182d_driver = {
+        .driver = {
+                .name = US5182D_DRV_NAME,
+                .acpi_match_table = ACPI_PTR(us5182d_acpi_match),
+        },
+        .probe = us5182d_probe,
+        .remove = us5182d_remove,
+        .id_table = us5182d_id,
+
+};
+module_i2c_driver(us5182d_driver);
+
+MODULE_AUTHOR("Adriana Reus <adriana.reus@intel.com>");
+MODULE_DESCRIPTION("Driver for us5182d Proximity and Light Sensor");
+MODULE_LICENSE("GPL v2");