1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
new file mode 100644
index 0000000000..2d91caf24d
--- /dev/null
+++ b/drivers/iio/light/acpi-als.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ACPI Ambient Light Sensor Driver
+ *
+ * Based on ALS driver:
+ * Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
+ *
+ * Rework for IIO subsystem:
+ * Copyright (C) 2012-2013 Martin Liska <marxin.liska@gmail.com>
+ *
+ * Final cleanup and debugging:
+ * Copyright (C) 2013-2014 Marek Vasut <marex@denx.de>
+ * Copyright (C) 2015 Gabriele Mazzotta <gabriele.mzt@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <linux/mutex.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#define ACPI_ALS_CLASS			"als"
+#define ACPI_ALS_DEVICE_NAME		"acpi-als"
+#define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
+
+/*
+ * So far, there's only one channel in here, but the specification for
+ * ACPI0008 says there can be more to what the block can report. Like
+ * chromaticity and such. We are ready for incoming additions!
+ */
+static const struct iio_chan_spec acpi_als_channels[] = {
+	{
+		.type		= IIO_LIGHT,
+		.scan_type	= {
+			.sign		= 's',
+			.realbits	= 32,
+			.storagebits	= 32,
+		},
+		/* _RAW is here for backward ABI compatibility */
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) |
+					  BIT(IIO_CHAN_INFO_PROCESSED),
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+/*
+ * The event buffer contains timestamp and all the data from
+ * the ACPI0008 block. There are multiple, but so far we only
+ * support _ALI (illuminance): One channel, padding and timestamp.
+ */
+#define ACPI_ALS_EVT_BUFFER_SIZE		\
+	(sizeof(s32) + sizeof(s32) + sizeof(s64))
+
+struct acpi_als {
+	struct acpi_device	*device;
+	struct mutex		lock;
+	struct iio_trigger	*trig;
+
+	s32 evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE / sizeof(s32)]  __aligned(8);
+};
+
+/*
+ * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
+ * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
+ * special.
+ *
+ * The _ALR property returns tables that can be used to fine-tune the values
+ * reported by the other props based on the particular hardware type and it's
+ * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
+ *
+ * So far, we support only ALI (illuminance).
+ */
+#define ACPI_ALS_ILLUMINANCE	"_ALI"
+#define ACPI_ALS_CHROMATICITY	"_ALC"
+#define ACPI_ALS_COLOR_TEMP	"_ALT"
+#define ACPI_ALS_POLLING	"_ALP"
+#define ACPI_ALS_TABLES		"_ALR"
+
+static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
+{
+	unsigned long long temp_val;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(als->device->handle, prop, NULL,
+				       &temp_val);
+
+	if (ACPI_FAILURE(status)) {
+		acpi_evaluation_failure_warn(als->device->handle, prop, status);
+		return -EIO;
+	}
+
+	*val = temp_val;
+
+	return 0;
+}
+
+static void acpi_als_notify(struct acpi_device *device, u32 event)
+{
+	struct iio_dev *indio_dev = acpi_driver_data(device);
+	struct acpi_als *als = iio_priv(indio_dev);
+
+	if (iio_buffer_enabled(indio_dev) && iio_trigger_using_own(indio_dev)) {
+		switch (event) {
+		case ACPI_ALS_NOTIFY_ILLUMINANCE:
+			iio_trigger_poll_nested(als->trig);
+			break;
+		default:
+			/* Unhandled event */
+			dev_dbg(&device->dev,
+				"Unhandled ACPI ALS event (%08x)!\n",
+				event);
+		}
+	}
+}
+
+static int acpi_als_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int *val,
+			     int *val2, long mask)
+{
+	struct acpi_als *als = iio_priv(indio_dev);
+	s32 temp_val;
+	int ret;
+
+	if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
+		return -EINVAL;
+
+	/* we support only illumination (_ALI) so far. */
+	if (chan->type != IIO_LIGHT)
+		return -EINVAL;
+
+	ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
+	if (ret < 0)
+		return ret;
+
+	*val = temp_val;
+
+	return IIO_VAL_INT;
+}
+
+static const struct iio_info acpi_als_info = {
+	.read_raw		= acpi_als_read_raw,
+};
+
+static irqreturn_t acpi_als_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct acpi_als *als = iio_priv(indio_dev);
+	s32 *buffer = als->evt_buffer;
+	s32 val;
+	int ret;
+
+	mutex_lock(&als->lock);
+
+	ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
+	if (ret < 0)
+		goto out;
+	*buffer = val;
+
+	/*
+	 * When coming from own trigger via polls, set polling function
+	 * timestamp here. Given ACPI notifier is already in a thread and call
+	 * function directly, there is no need to set the timestamp in the
+	 * notify function.
+	 *
+	 * If the timestamp was actually 0, the timestamp is set one more time.
+	 */
+	if (!pf->timestamp)
+		pf->timestamp = iio_get_time_ns(indio_dev);
+
+	iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp);
+out:
+	mutex_unlock(&als->lock);
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int acpi_als_add(struct acpi_device *device)
+{
+	struct device *dev = &device->dev;
+	struct iio_dev *indio_dev;
+	struct acpi_als *als;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*als));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	als = iio_priv(indio_dev);
+
+	device->driver_data = indio_dev;
+	als->device = device;
+	mutex_init(&als->lock);
+
+	indio_dev->name = ACPI_ALS_DEVICE_NAME;
+	indio_dev->info = &acpi_als_info;
+	indio_dev->channels = acpi_als_channels;
+	indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
+
+	als->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
+					   iio_device_id(indio_dev));
+	if (!als->trig)
+		return -ENOMEM;
+
+	ret = devm_iio_trigger_register(dev, als->trig);
+	if (ret)
+		return ret;
+	/*
+	 * Set hardware trigger by default to let events flow when
+	 * BIOS support notification.
+	 */
+	indio_dev->trig = iio_trigger_get(als->trig);
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+					      iio_pollfunc_store_time,
+					      acpi_als_trigger_handler,
+					      NULL);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct acpi_device_id acpi_als_device_ids[] = {
+	{"ACPI0008", 0},
+	{},
+};
+
+MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
+
+static struct acpi_driver acpi_als_driver = {
+	.name	= "acpi_als",
+	.class	= ACPI_ALS_CLASS,
+	.ids	= acpi_als_device_ids,
+	.ops = {
+		.add	= acpi_als_add,
+		.notify	= acpi_als_notify,
+	},
+};
+
+module_acpi_driver(acpi_als_driver);
+
+MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
+MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
+MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
+MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");