iio: acpi: Add ACPI0008 ALS driver

PATCH In review Manuel Stahl 2 participants 2 messages Dec 23, 2014 – Dec 26, 2014 IIO

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Manuel Stahl

author

2014-12-23 15:39 UTC #0 lore raw

PATCH v7 1/1 iio: acpi: Add ACPI0008 ALS driver

Add basic implementation of the ACPI0008 Ambient Light Sensor driver. This driver currently supports only the ALI property, yet is ready to be easily extended to handle ALC, ALT, ALP ones as well.

V2: Fix the channel mask, so it's really reading RAW data.
V3: Put scan timestamp into the buffer only when enabled,
Set the light sensor ID to 0 instead of 1
V4: Select IIO_TRIGGERED_BUFFER as we need it here
V5: Use irq_work to trigger the buffer
Use module_acpi_driver()
V6: Align with 3.15-rc7
Use iio_push_to_buffers_with_timestamp()
Use iio_trigger_set_drvdata()
Use .info_mask_separate
Use devm_iio_device_alloc()
Stuff the event buffer into struct acpi_als so we don't alloc mem
twice
Compute the evt_buffer size automatically based on
acpi_als_channels[]
Implement .validate_device() and .validate_trigger() Tested on MacBook Air (Mid 2013) and Acer IconiaTab W510V2: Fix the
channel mask, so it's really reading RAW data.
V3: Put scan timestamp into the buffer only when enabled,
Set the light sensor ID to 0 instead of 1
V4: Select IIO_TRIGGERED_BUFFER as we need it here
V5: Use irq_work to trigger the buffer
Use module_acpi_driver()
V6: Align with 3.15-rc7
Use iio_push_to_buffers_with_timestamp()
Use iio_trigger_set_drvdata()
Use .info_mask_separate
Use devm_iio_device_alloc()
Stuff the event buffer into struct acpi_als so we don't alloc mem
twice
Compute the evt_buffer size automatically based on
acpi_als_channels[]
Implement .validate_device() and .validate_trigger() Tested on MacBook Air (Mid 2013) and Acer IconiaTab W510
V7: Remove IIO trigger support (As suggested by Jonathan)
Add enable function (needed on Zenbook)
Tested on Asus Zenbook UX301L

drivers/iio/light/acpi-als.c +318 -0

diff -uprN a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
@@ -0,0 +1,318 @@
+/*
+ * ACPI Ambient Light Sensor Driver
+ *
+ * Based on ALS driver:
+ * Copyright (C) 2009 Zhang Rui <[email protected]>
+ *
+ * Rework for IIO subsystem:
+ * Copyright (C) 2012-2013 Martin Liska <[email protected]>
+ *
+ * Final cleanup and debugging:
+ * Copyright (C) 2013-2014 Marek Vasut <[email protected]>
+ * Copyright (C) 2014 Manuel Stahl <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
+
+#define ACPI_ALS_CLASS			"als"
+#define ACPI_ALS_DEVICE_NAME		"acpi-als"
+#define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
+
+ACPI_MODULE_NAME("acpi-als");
+
+/*
+ * 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		= 'u',
+			.realbits	= 10,
+			.storagebits	= 16,
+		},
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
+	},
+};
+
+/*
+ * The event buffer contains timestamp and all the data from
+ * the ACPI0008 block. There are multiple, but so far we only
+ * support _ALI (illuminance). Once someone adds new channels
+ * to acpi_als_channels[], the evt_buffer below will grow
+ * automatically.
+ */
+#define EVT_NR_SOURCES		ARRAY_SIZE(acpi_als_channels)
+#define EVT_BUFFER_SIZE		\
+	(sizeof(int64_t) + (EVT_NR_SOURCES * sizeof(uint16_t)))
+
+struct acpi_als {
+	struct acpi_device	*device;
+	struct mutex		lock;
+
+	uint16_t		evt_buffer[EVT_BUFFER_SIZE];
+};
+
+/*
+ * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
+ * and ALP can all be handled by 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 int32_t als_read_value(struct acpi_als *als, char *prop)
+{
+	unsigned long long illuminance;
+	acpi_status status;
+
+	status = acpi_evaluate_integer(als->device->handle,
+				prop, NULL, &illuminance);
+
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status,
+				"Error reading ALS illuminance"));
+		return -EIO;
+	}
+
+	return illuminance;
+}
+
+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);
+	uint16_t *buffer = als->evt_buffer;
+	int64_t time_ns = iio_get_time_ns();
+	int32_t val;
+
+	mutex_lock(&als->lock);
+
+	memset(buffer, 0, EVT_BUFFER_SIZE);
+
+	switch (event) {
+	case ACPI_ALS_NOTIFY_ILLUMINANCE:
+		val = als_read_value(als, ACPI_ALS_ILLUMINANCE);
+		if (val < 0)
+			goto err_ret;
+		*buffer++ = (uint16_t)val;
+		break;
+	default: /* Unhandled event */
+		dev_dbg(&device->dev, "Unhandled ACPI ALS event (%08x)!\n",
+			event);
+		goto err_ret;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev,
+					   (uint8_t *)als->evt_buffer,
+					   time_ns);
+
+err_ret:
+	mutex_unlock(&als->lock);
+}
+
+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);
+
+	if (mask != IIO_CHAN_INFO_RAW)
+		return -EINVAL;
+
+	/* we support only illumination (_ALI) so far. */
+	if (chan->type != IIO_LIGHT)
+		return -EINVAL;
+
+	*val = als_read_value(als, ACPI_ALS_ILLUMINANCE);
+	if (*val < 0)
+		return *val;
+
+	return IIO_VAL_INT;
+}
+
+static acpi_handle acpi_handle_from_string(const char *str)
+{
+	acpi_handle handle;
+	acpi_status handle_status;
+
+	handle_status = acpi_get_handle(NULL, (acpi_string)str, &handle);
+	return ACPI_FAILURE(handle_status) ? NULL : handle;
+}
+
+static int acpi_als_enable(struct acpi_device *device, int enable)
+{
+	acpi_handle handle;
+	acpi_status result;
+	struct acpi_object_list arg;
+	union acpi_object param;
+
+	arg.count = 1;
+	arg.pointer = &param;
+	param.type = ACPI_TYPE_INTEGER;
+
+	handle = acpi_handle_from_string("\\_SB.PCI0.LPCB.EC0.TALS");
+	if (handle == NULL) {
+		dev_err(&device->dev, "unable to get handle for \\_SB.PCI0.LPCB.EC0.TALS\n");
+		return -EIO;
+	}
+
+	param.integer.value = enable;
+	result = acpi_evaluate_object(handle, NULL, &arg, NULL);
+
+	if (enable) {
+		handle = acpi_handle_from_string("\\_SB.ATKD.ALSC");
+		if (handle == NULL) {
+			dev_err(&device->dev, "unable to get handle for \\_SB.PCI0.LPCB.EC0.TALS\n");
+			return -EIO;
+		}
+		result = acpi_evaluate_object(handle, NULL, &arg, NULL);
+	}
+
+	return 0;
+}
+
+static int acpi_als_buffer_register(struct iio_dev *indio_dev)
+{
+	struct iio_buffer *buffer;
+	int ret;
+
+	buffer = iio_kfifo_allocate(indio_dev);
+	if (!buffer)
+		return -ENOMEM;
+
+	iio_device_attach_buffer(indio_dev, buffer);
+	indio_dev->modes |= INDIO_BUFFER_HARDWARE;
+
+	ret = iio_buffer_register(indio_dev,
+				  indio_dev->channels,
+				  indio_dev->num_channels);
+	if (ret)
+		goto error_kfifo_free;
+
+	return 0;
+
+error_kfifo_free:
+	iio_kfifo_free(indio_dev->buffer);
+	return ret;
+}
+
+static void acpi_als_buffer_unregister(struct iio_dev *indio_dev)
+{
+	iio_kfifo_free(indio_dev->buffer);
+	iio_buffer_unregister(indio_dev);
+}
+
+static const struct iio_info acpi_als_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= acpi_als_read_raw,
+};
+
+static int acpi_als_add(struct acpi_device *device)
+{
+	struct acpi_als *als;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&device->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->dev.parent = &device->dev;
+	indio_dev->info = &acpi_als_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = acpi_als_channels;
+	indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
+
+	ret = acpi_als_enable(device, 1);
+	if (ret < 0)
+		return ret;
+
+	ret = acpi_als_buffer_register(indio_dev);
+	if (ret < 0)
+		return ret;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto err_ret;
+
+	return 0;
+
+err_ret:
+	acpi_als_buffer_unregister(indio_dev);
+	return ret;
+}
+
+static int acpi_als_remove(struct acpi_device *device)
+{
+	struct iio_dev *indio_dev = acpi_driver_data(device);
+
+	iio_device_unregister(indio_dev);
+	acpi_als_buffer_unregister(indio_dev);
+	acpi_als_enable(device, 0);
+	return 0;
+}
+
+static const struct acpi_device_id acpi_als_device_ids[] = {
+	{"ACPI0008", 0},
+	{"", 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,
+		.remove	= acpi_als_remove,
+		.notify	= acpi_als_notify,
+	},
+};
+
+module_acpi_driver(acpi_als_driver);
+
+MODULE_AUTHOR("Zhang Rui <[email protected]>");
+MODULE_AUTHOR("Martin Liska <[email protected]>");
+MODULE_AUTHOR("Marek Vasut <[email protected]>");
+MODULE_AUTHOR("Manuel Stahl <[email protected]>");
+MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");

drivers/iio/light/Kconfig +0 -0

diff -uprN a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
@@ -5,6 +5,17 @@

menu "Light sensors"

+config ACPI_ALS
+ tristate "ACPI Ambient Light Sensor"
+ depends on ACPI
+ select IIO_BUFFER
+ select IIO_KFIFO_BUF
+ help
+ Support for the ACPI0008 Ambient Light Sensor.
+
+ This driver can also be built as a module. If so, the module
+ will be called acpi-als.
+
config ADJD_S311
tristate "ADJD-S311-CR999 digital color sensor" select IIO_BUFFER

drivers/iio/light/Makefile +0 -0

diff -uprN a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
@@ -3,6 +3,7 @@

# When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_ACPI_ALS) += acpi-als.o
obj-$(CONFIG_ADJD_S311) += adjd_s311.o
obj-$(CONFIG_APDS9300) += apds9300.o
obj-$(CONFIG_CM32181) += cm32181.o

Jonathan Cameron

maintainer

2014-12-26 11:02 UTC #1 lore raw

Quoted 4 lines · Manuel Stahl

Add basic implementation of the ACPI0008 Ambient Light Sensor driver. This driver currently supports only the ALI property, yet is ready to be easily extended to handle ALC, ALT, ALP ones as well.

Quoted 15 lines

V2: Fix the channel mask, so it's really reading RAW data.
V3: Put scan timestamp into the buffer only when enabled,
Set the light sensor ID to 0 instead of 1
V4: Select IIO_TRIGGERED_BUFFER as we need it here
V5: Use irq_work to trigger the buffer
Use module_acpi_driver()
V6: Align with 3.15-rc7
Use iio_push_to_buffers_with_timestamp()
Use iio_trigger_set_drvdata()
Use .info_mask_separate
Use devm_iio_device_alloc()
Stuff the event buffer into struct acpi_als so we don't alloc mem twice
Compute the evt_buffer size automatically based on acpi_als_channels[]
Implement .validate_device() and .validate_trigger()
Tested on MacBook Air (Mid 2013) and Acer IconiaTab W510V2: Fix the channel mask, so it's really reading RAW data.

Change log doubled up for some reason!

Quoted 9 lines

V3: Put scan timestamp into the buffer only when enabled,
Set the light sensor ID to 0 instead of 1
V4: Select IIO_TRIGGERED_BUFFER as we need it here
V5: Use irq_work to trigger the buffer
Use module_acpi_driver()
V6: Align with 3.15-rc7
Use iio_push_to_buffers_with_timestamp()
Use iio_trigger_set_drvdata()
Use .info_mask_separate

Quoted 8 lines

Use devm_iio_device_alloc()
Stuff the event buffer into struct acpi_als so we don't alloc mem twice Compute the evt_buffer size automatically based on acpi_als_channels[] Implement .validate_device() and .validate_trigger()
Tested on MacBook Air (Mid 2013) and Acer IconiaTab W510
V7: Remove IIO trigger support (As suggested by Jonathan)
Add enable function (needed on Zenbook)
Tested on Asus Zenbook UX301L

Also - no signoffs etc

Few bits below...

In particular we are using the hardware buffer stuff here and it isn't a hardware buffer. Clearly that doesn't matter from the point of view of what the code does but for clarity I think we should add an additional buffering type for non triggered software buffers like this one. That is those that come off hardware that is already bundling the data up in a form that doesn't really fit the triggered model.

By coincidence most (perhaps all) the other drivers that have used a non triggered software buffer have also had hardware buffer backends so the lack of such a buffer type hasn't caused confusion before.

Jonathan

Quoted 210 lines

diff -uprN a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +205 -0

@@ -0,0 +1,318 @@
+/*
+ * ACPI Ambient Light Sensor Driver
+ *
+ * Based on ALS driver:
+ * Copyright (C) 2009 Zhang Rui <[email protected]>
+ *
+ * Rework for IIO subsystem:
+ * Copyright (C) 2012-2013 Martin Liska <[email protected]>
+ *
+ * Final cleanup and debugging:
+ * Copyright (C) 2013-2014 Marek Vasut <[email protected]>
+ * Copyright (C) 2014 Manuel Stahl <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/kfifo_buf.h>
+
+#define ACPI_ALS_CLASS            "als"
+#define ACPI_ALS_DEVICE_NAME        "acpi-als"
+#define ACPI_ALS_NOTIFY_ILLUMINANCE    0x80
+
+ACPI_MODULE_NAME("acpi-als");
+
+/*
+ * 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        = 'u',
+            .realbits    = 10,
+            .storagebits    = 16,
+        },
+        .info_mask_separate    = BIT(IIO_CHAN_INFO_RAW),
+    },
+};
+
+/*
+ * The event buffer contains timestamp and all the data from
+ * the ACPI0008 block. There are multiple, but so far we only
+ * support _ALI (illuminance). Once someone adds new channels
+ * to acpi_als_channels[], the evt_buffer below will grow
+ * automatically.
+ */
+#define EVT_NR_SOURCES        ARRAY_SIZE(acpi_als_channels)
+#define EVT_BUFFER_SIZE        \
+    (sizeof(int64_t) + (EVT_NR_SOURCES * sizeof(uint16_t)))
+
+struct acpi_als {
+    struct acpi_device    *device;
+    struct mutex        lock;
+
+    uint16_t        evt_buffer[EVT_BUFFER_SIZE];
+};
+
+/*
+ * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
+ * and ALP can all be handled by 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 int32_t als_read_value(struct acpi_als *als, char *prop)
+{
+    unsigned long long illuminance;
+    acpi_status status;
+
+    status = acpi_evaluate_integer(als->device->handle,
+                prop, NULL, &illuminance);
+
+    if (ACPI_FAILURE(status)) {
+        ACPI_EXCEPTION((AE_INFO, status,
+                "Error reading ALS illuminance"));
+        return -EIO;
+    }
+
+    return illuminance;
+}
+
+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);
+    uint16_t *buffer = als->evt_buffer;
+    int64_t time_ns = iio_get_time_ns();
+    int32_t val;
+
+    mutex_lock(&als->lock);
+
+    memset(buffer, 0, EVT_BUFFER_SIZE);
+
+    switch (event) {
+    case ACPI_ALS_NOTIFY_ILLUMINANCE:
+        val = als_read_value(als, ACPI_ALS_ILLUMINANCE);
+        if (val < 0)
+            goto err_ret;
+        *buffer++ = (uint16_t)val;
+        break;
+    default: /* Unhandled event */
+        dev_dbg(&device->dev, "Unhandled ACPI ALS event (%08x)!\n",
+            event);
+        goto err_ret;
+    }
+
+    iio_push_to_buffers_with_timestamp(indio_dev,
+                       (uint8_t *)als->evt_buffer,
+                       time_ns);
+
+err_ret:
+    mutex_unlock(&als->lock);
+}
+
+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);
+
+    if (mask != IIO_CHAN_INFO_RAW)
+        return -EINVAL;
+
+    /* we support only illumination (_ALI) so far. */
+    if (chan->type != IIO_LIGHT)
+        return -EINVAL;
+
+    *val = als_read_value(als, ACPI_ALS_ILLUMINANCE);
+    if (*val < 0)
+        return *val;
+
+    return IIO_VAL_INT;
+}
+
+static acpi_handle acpi_handle_from_string(const char *str)
+{
+    acpi_handle handle;
+    acpi_status handle_status;
+
+    handle_status = acpi_get_handle(NULL, (acpi_string)str, &handle);
+    return ACPI_FAILURE(handle_status) ? NULL : handle;
+}
+
+static int acpi_als_enable(struct acpi_device *device, int enable)
+{
+    acpi_handle handle;
+    acpi_status result;
+    struct acpi_object_list arg;
+    union acpi_object param;
+
+    arg.count = 1;
+    arg.pointer = &param;
+    param.type = ACPI_TYPE_INTEGER;
+
+    handle = acpi_handle_from_string("\\_SB.PCI0.LPCB.EC0.TALS");
+    if (handle == NULL) {
+        dev_err(&device->dev, "unable to get handle for \\_SB.PCI0.LPCB.EC0.TALS\n");
+        return -EIO;
+    }
+
+    param.integer.value = enable;
+    result = acpi_evaluate_object(handle, NULL, &arg, NULL);
+
+    if (enable) {
+        handle = acpi_handle_from_string("\\_SB.ATKD.ALSC");
+        if (handle == NULL) {
+            dev_err(&device->dev, "unable to get handle for \\_SB.PCI0.LPCB.EC0.TALS\n");
+            return -EIO;
+        }
+        result = acpi_evaluate_object(handle, NULL, &arg, NULL);
+    }
+
+    return 0;
+}
+
+static int acpi_als_buffer_register(struct iio_dev *indio_dev)

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 line 215

Quoted 10 lines

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +10 -0
+{
+    struct iio_buffer *buffer;
+    int ret;
+
+    buffer = iio_kfifo_allocate(indio_dev);
+    if (!buffer)
+        return -ENOMEM;
+
+    iio_device_attach_buffer(indio_dev, buffer);
+    indio_dev->modes |= INDIO_BUFFER_HARDWARE;

Hmm. It's not actually a hardware buffer is it?
I think we need a new buffer type to indicate non triggered software buffers.

Quoted 8 lines

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +8 -0
+
+    ret = iio_buffer_register(indio_dev,
+                  indio_dev->channels,
+                  indio_dev->num_channels);
+    if (ret)
+        goto error_kfifo_free;
+
+    return 0;

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 line 233

Quoted 10 lines

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +10 -0
+
+error_kfifo_free:
+    iio_kfifo_free(indio_dev->buffer);
+    return ret;
+}
+
+static void acpi_als_buffer_unregister(struct iio_dev *indio_dev)
+{
+    iio_kfifo_free(indio_dev->buffer);
+    iio_buffer_unregister(indio_dev);

Unregister before free.

Quoted 46 lines

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +46 -0

+}
+
+static const struct iio_info acpi_als_info = {
+    .driver_module        = THIS_MODULE,
+    .read_raw        = acpi_als_read_raw,
+};
+
+static int acpi_als_add(struct acpi_device *device)
+{
+    struct acpi_als *als;
+    struct iio_dev *indio_dev;
+    int ret;
+
+    indio_dev = devm_iio_device_alloc(&device->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->dev.parent = &device->dev;
+    indio_dev->info = &acpi_als_info;
+    indio_dev->modes = INDIO_DIRECT_MODE;
+    indio_dev->channels = acpi_als_channels;
+    indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
+
+    ret = acpi_als_enable(device, 1);
+    if (ret < 0)
+        return ret;
+
+    ret = acpi_als_buffer_register(indio_dev);
+    if (ret < 0)
+        return ret;
+
+    ret = iio_device_register(indio_dev);
+    if (ret < 0)
+        goto err_ret;
+
+    return 0;
+
+err_ret:
+    acpi_als_buffer_unregister(indio_dev);

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 line 289

Quoted 10 lines

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +10 -0
+    return ret;
+}
+
+static int acpi_als_remove(struct acpi_device *device)
+{
+    struct iio_dev *indio_dev = acpi_driver_data(device);
+
+    iio_device_unregister(indio_dev);
+    acpi_als_buffer_unregister(indio_dev);
+    acpi_als_enable(device, 0);

Blank line here would be nice.

Quoted 68 lines

drivers/iio/light/acpi-als.c 2014-12-23 16:21:24.763821632 +0100 renamed from drivers/iio/light/acpi-als.c 1970-01-01 01:00:00.000000000 +0100 +29 -0
+    return 0;
+}
+
+static const struct acpi_device_id acpi_als_device_ids[] = {
+    {"ACPI0008", 0},
+    {"", 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,
+        .remove    = acpi_als_remove,
+        .notify    = acpi_als_notify,
+    },
+};
+
+module_acpi_driver(acpi_als_driver);
+
+MODULE_AUTHOR("Zhang Rui <[email protected]>");
+MODULE_AUTHOR("Martin Liska <[email protected]>");
+MODULE_AUTHOR("Marek Vasut <[email protected]>");
+MODULE_AUTHOR("Manuel Stahl <[email protected]>");
+MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");
diff -uprN a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
drivers/iio/light/Kconfig 2014-12-23 16:23:34.275823164 +0100 renamed from drivers/iio/light/Kconfig 2014-12-23 16:13:28.219815997 +0100 +0 -0
@@ -5,6 +5,17 @@
 
menu "Light sensors"
drivers/iio/light/Kconfig 2014-12-23 16:23:34.275823164 +0100 renamed from drivers/iio/light/Kconfig 2014-12-23 16:13:28.219815997 +0100 +11 -0
+config ACPI_ALS
+    tristate "ACPI Ambient Light Sensor"
+    depends on ACPI
+    select IIO_BUFFER
+    select IIO_KFIFO_BUF
+    help
+     Support for the ACPI0008 Ambient Light Sensor.
+
+     This driver can also be built as a module.  If so, the module
+     will be called acpi-als.
+
config ADJD_S311
tristate "ADJD-S311-CR999 digital color sensor" select IIO_BUFFER
diff -uprN a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
drivers/iio/light/Makefile 2014-12-23 15:11:18.923771897 +0100 renamed from drivers/iio/light/Makefile 2014-12-23 16:13:03.575815706 +0100 +1 -0
@@ -3,6 +3,7 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_ACPI_ALS)        += acpi-als.o
obj-$(CONFIG_ADJD_S311) += adjd_s311.o
obj-$(CONFIG_APDS9300) += apds9300.o
obj-$(CONFIG_CM32181) += cm32181.o
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