This patch adds support for the Azoteq IQS621 ambient light sensor,
capable of reporting intensity directly in units of lux.

Signed-off-by: Jeff LaBundy <j...@labundy.com>
---
 drivers/iio/light/Kconfig      |  10 ++
 drivers/iio/light/Makefile     |   1 +
 drivers/iio/light/iqs621-als.c | 361 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 372 insertions(+)
 create mode 100644 drivers/iio/light/iqs621-als.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 4a1a883..aad26dc 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -162,6 +162,16 @@ config GP2AP020A00F
          To compile this driver as a module, choose M here: the
          module will be called gp2ap020a00f.
 
+config IQS621_ALS
+       tristate "Azoteq IQS621 ambient light sensor"
+       depends on MFD_IQS62X
+       help
+         Say Y here if you want to build support for the Azoteq IQS621
+         ambient light sensor.
+
+         To compile this driver as a module, choose M here: the module
+         will be called iqs621-als.
+
 config SENSORS_ISL29018
        tristate "Intersil 29018 light and proximity sensor"
        depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index 00d1f9b..aa34358 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_IIO_CROS_EC_LIGHT_PROX) += cros_ec_light_prox.o
 obj-$(CONFIG_GP2AP020A00F)     += gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)   += hid-sensor-als.o
 obj-$(CONFIG_HID_SENSOR_PROX)  += hid-sensor-prox.o
+obj-$(CONFIG_IQS621_ALS)       += iqs621-als.o
 obj-$(CONFIG_SENSORS_ISL29018) += isl29018.o
 obj-$(CONFIG_SENSORS_ISL29028) += isl29028.o
 obj-$(CONFIG_ISL29125)         += isl29125.o
diff --git a/drivers/iio/light/iqs621-als.c b/drivers/iio/light/iqs621-als.c
new file mode 100644
index 0000000..92a6173
--- /dev/null
+++ b/drivers/iio/light/iqs621-als.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Azoteq IQS621 Ambient Light Sensor
+ *
+ * Copyright (C) 2019
+ * Author: Jeff LaBundy <j...@labundy.com>
+ */
+
+#include <linux/device.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/iqs62x.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define IQS621_ALS_FLAGS                       0x16
+#define IQS621_ALS_FLAGS_LIGHT                 BIT(7)
+
+#define IQS621_ALS_UI_OUT                      0x17
+
+#define IQS621_ALS_THRESH_DARK                 0x80
+#define IQS621_ALS_THRESH_DARK_MAX             1020
+#define IQS621_ALS_THRESH_DARK_SHIFT           2
+
+#define IQS621_ALS_THRESH_LIGHT                        0x81
+#define IQS621_ALS_THRESH_LIGHT_MAX            4080
+#define IQS621_ALS_THRESH_LIGHT_SHIFT          4
+
+struct iqs621_als_private {
+       struct iqs62x_core *iqs62x;
+       struct notifier_block notifier;
+       struct mutex lock;
+       bool event_en;
+       u8 thresh_light;
+       u8 thresh_dark;
+       u8 flags;
+};
+
+static int iqs621_als_init(struct iqs621_als_private *iqs621_als)
+{
+       struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+       unsigned int val;
+       int error;
+
+       mutex_lock(&iqs621_als->lock);
+
+       error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_LIGHT,
+                            iqs621_als->thresh_light);
+       if (error)
+               goto err_mutex;
+
+       error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_DARK,
+                            iqs621_als->thresh_dark);
+       if (error)
+               goto err_mutex;
+
+       error = regmap_read(iqs62x->map, IQS621_ALS_FLAGS, &val);
+       if (error)
+               goto err_mutex;
+       iqs621_als->flags = val;
+
+       error = regmap_update_bits(iqs62x->map, IQS620_GLBL_EVENT_MASK,
+                                  iqs62x->dev_desc->als_mask,
+                                  iqs621_als->event_en ? 0 : 0xFF);
+
+err_mutex:
+       mutex_unlock(&iqs621_als->lock);
+
+       return error;
+}
+
+static int iqs621_als_notifier(struct notifier_block *notifier,
+                              unsigned long event_flags, void *context)
+{
+       struct iqs62x_event_data *event_data = context;
+       struct iqs621_als_private *iqs621_als;
+       struct iio_dev *indio_dev;
+       enum iio_event_direction dir;
+       int error;
+
+       iqs621_als = container_of(notifier, struct iqs621_als_private,
+                                 notifier);
+       indio_dev = iio_priv_to_dev(iqs621_als);
+
+       if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
+               error = iqs621_als_init(iqs621_als);
+               if (error) {
+                       dev_err(indio_dev->dev.parent,
+                               "Failed to re-initialize device: %d\n", error);
+                       return NOTIFY_BAD;
+               }
+
+               return NOTIFY_OK;
+       }
+
+       if (!((event_data->als_flags ^ iqs621_als->flags) &
+           IQS621_ALS_FLAGS_LIGHT))
+               return NOTIFY_DONE;
+
+       iqs621_als->flags = event_data->als_flags;
+
+       if (!iqs621_als->event_en)
+               return NOTIFY_OK;
+
+       dir = iqs621_als->flags & IQS621_ALS_FLAGS_LIGHT ? IIO_EV_DIR_RISING :
+                                                          IIO_EV_DIR_FALLING;
+
+       iio_push_event(indio_dev,
+                      IIO_UNMOD_EVENT_CODE(IIO_LIGHT, 0,
+                                           IIO_EV_TYPE_THRESH, dir),
+                      iio_get_time_ns(indio_dev));
+
+       return NOTIFY_OK;
+}
+
+static void iqs621_als_notifier_unregister(void *context)
+{
+       struct iqs621_als_private *iqs621_als = context;
+       struct iio_dev *indio_dev = iio_priv_to_dev(iqs621_als);
+       int error;
+
+       error = blocking_notifier_chain_unregister(&iqs621_als->iqs62x->nh,
+                                                  &iqs621_als->notifier);
+       if (error)
+               dev_err(indio_dev->dev.parent,
+                       "Failed to unregister notifier: %d\n", error);
+}
+
+static int iqs621_als_read_raw(struct iio_dev *indio_dev,
+                              struct iio_chan_spec const *chan,
+                              int *val, int *val2, long mask)
+{
+       struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+       struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+       int error;
+       __le16 val_buf;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+               error = regmap_raw_read(iqs62x->map, IQS621_ALS_UI_OUT,
+                                       &val_buf, sizeof(val_buf));
+               if (error)
+                       return error;
+
+               *val = le16_to_cpu(val_buf);
+               return IIO_VAL_INT;
+
+       default:
+               return -EINVAL;
+       }
+}
+
+static int iqs621_als_read_event_config(struct iio_dev *indio_dev,
+                                       const struct iio_chan_spec *chan,
+                                       enum iio_event_type type,
+                                       enum iio_event_direction dir)
+{
+       struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+
+       return iqs621_als->event_en;
+}
+
+static int iqs621_als_write_event_config(struct iio_dev *indio_dev,
+                                        const struct iio_chan_spec *chan,
+                                        enum iio_event_type type,
+                                        enum iio_event_direction dir,
+                                        int state)
+{
+       struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+       struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+       int error;
+
+       mutex_lock(&iqs621_als->lock);
+
+       error = regmap_update_bits(iqs62x->map, IQS620_GLBL_EVENT_MASK,
+                                  iqs62x->dev_desc->als_mask,
+                                  state ? 0 : 0xFF);
+       if (!error)
+               iqs621_als->event_en = state;
+
+       mutex_unlock(&iqs621_als->lock);
+
+       return error;
+}
+
+static int iqs621_als_read_event_value(struct iio_dev *indio_dev,
+                                      const struct iio_chan_spec *chan,
+                                      enum iio_event_type type,
+                                      enum iio_event_direction dir,
+                                      enum iio_event_info info,
+                                      int *val, int *val2)
+{
+       struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+
+       switch (dir) {
+       case IIO_EV_DIR_RISING:
+               *val = iqs621_als->thresh_light;
+               *val <<= IQS621_ALS_THRESH_LIGHT_SHIFT;
+               return IIO_VAL_INT;
+
+       case IIO_EV_DIR_FALLING:
+               *val = iqs621_als->thresh_dark;
+               *val <<= IQS621_ALS_THRESH_DARK_SHIFT;
+               return IIO_VAL_INT;
+
+       default:
+               return -EINVAL;
+       }
+}
+
+static int iqs621_als_write_event_value(struct iio_dev *indio_dev,
+                                       const struct iio_chan_spec *chan,
+                                       enum iio_event_type type,
+                                       enum iio_event_direction dir,
+                                       enum iio_event_info info,
+                                       int val, int val2)
+{
+       struct iqs621_als_private *iqs621_als = iio_priv(indio_dev);
+       struct iqs62x_core *iqs62x = iqs621_als->iqs62x;
+       int error = -EINVAL;
+
+       mutex_lock(&iqs621_als->lock);
+
+       switch (dir) {
+       case IIO_EV_DIR_RISING:
+               if (val > IQS621_ALS_THRESH_LIGHT_MAX)
+                       break;
+               val >>= IQS621_ALS_THRESH_LIGHT_SHIFT;
+
+               error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_LIGHT, val);
+               if (!error)
+                       iqs621_als->thresh_light = val;
+               break;
+
+       case IIO_EV_DIR_FALLING:
+               if (val > IQS621_ALS_THRESH_DARK)
+                       break;
+               val >>= IQS621_ALS_THRESH_DARK_SHIFT;
+
+               error = regmap_write(iqs62x->map, IQS621_ALS_THRESH_DARK, val);
+               if (!error)
+                       iqs621_als->thresh_dark = val;
+               break;
+
+       default:
+               break;
+       }
+
+       mutex_unlock(&iqs621_als->lock);
+
+       return error;
+}
+
+static const struct iio_info iqs621_als_info = {
+       .read_raw = &iqs621_als_read_raw,
+       .read_event_config = iqs621_als_read_event_config,
+       .write_event_config = iqs621_als_write_event_config,
+       .read_event_value = iqs621_als_read_event_value,
+       .write_event_value = iqs621_als_write_event_value,
+};
+
+static const struct iio_event_spec iqs621_als_events[] = {
+       {
+               .type = IIO_EV_TYPE_THRESH,
+               .dir = IIO_EV_DIR_EITHER,
+               .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+       },
+       {
+               .type = IIO_EV_TYPE_THRESH,
+               .dir = IIO_EV_DIR_RISING,
+               .mask_separate = BIT(IIO_EV_INFO_VALUE),
+       },
+       {
+               .type = IIO_EV_TYPE_THRESH,
+               .dir = IIO_EV_DIR_FALLING,
+               .mask_separate = BIT(IIO_EV_INFO_VALUE),
+       },
+};
+
+static const struct iio_chan_spec iqs621_als_channels[] = {
+       {
+               .type = IIO_LIGHT,
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+               .event_spec = iqs621_als_events,
+               .num_event_specs = ARRAY_SIZE(iqs621_als_events),
+       },
+};
+
+static int iqs621_als_probe(struct platform_device *pdev)
+{
+       struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
+       struct iqs621_als_private *iqs621_als;
+       struct iio_dev *indio_dev;
+       unsigned int val;
+       int error;
+
+       indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*iqs621_als));
+       if (!indio_dev)
+               return -ENOMEM;
+
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->dev.parent = &pdev->dev;
+       indio_dev->channels = iqs621_als_channels;
+       indio_dev->num_channels = ARRAY_SIZE(iqs621_als_channels);
+       indio_dev->name = iqs62x->dev_desc->dev_name;
+       indio_dev->info = &iqs621_als_info;
+
+       iqs621_als = iio_priv(indio_dev);
+       iqs621_als->iqs62x = iqs62x;
+
+       error = regmap_read(iqs62x->map, IQS621_ALS_THRESH_LIGHT, &val);
+       if (error)
+               return error;
+       iqs621_als->thresh_light = val;
+
+       error = regmap_read(iqs62x->map, IQS621_ALS_THRESH_DARK, &val);
+       if (error)
+               return error;
+       iqs621_als->thresh_dark = val;
+
+       mutex_init(&iqs621_als->lock);
+
+       error = iqs621_als_init(iqs621_als);
+       if (error)
+               return error;
+
+       iqs621_als->notifier.notifier_call = iqs621_als_notifier;
+       error = blocking_notifier_chain_register(&iqs621_als->iqs62x->nh,
+                                                &iqs621_als->notifier);
+       if (error) {
+               dev_err(&pdev->dev, "Failed to register notifier: %d\n", error);
+               return error;
+       }
+
+       error = devm_add_action_or_reset(&pdev->dev,
+                                        iqs621_als_notifier_unregister,
+                                        iqs621_als);
+       if (error) {
+               dev_err(&pdev->dev, "Failed to add action: %d\n", error);
+               return error;
+       }
+
+       return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static struct platform_driver iqs621_als_platform_driver = {
+       .driver = {
+               .name   = IQS621_DRV_NAME_ALS,
+       },
+       .probe          = iqs621_als_probe,
+};
+module_platform_driver(iqs621_als_platform_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <j...@labundy.com>");
+MODULE_DESCRIPTION("Azoteq IQS621 Ambient Light Sensor");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" IQS621_DRV_NAME_ALS);
-- 
2.7.4

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