[PATCH V4 1/1] iio: add Capella CM32181 ambient light sensor driver.

[PATCH V4 1/1] iio: add Capella CM32181 ambient light sensor driver.

[Kevin Tsai]

Add Capella Microsystem CM32181 Ambient Light Sensor IIO driver.
This driver will convert raw data to lux value under open-air
condition. Change the calibscale based on the cover material.

Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
---
 .../devicetree/bindings/i2c/trivial-devices.txt    |   1 +
 drivers/iio/light/Kconfig                          |  11 +
 drivers/iio/light/Makefile                         |   1 +
 drivers/iio/light/cm32181.c                        | 380 +++++++++++++++++++++
 4 files changed, 393 insertions(+)
 create mode 100644 drivers/iio/light/cm32181.c

diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index b1cb341..c65f71c 100644
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -16,6 +16,7 @@ adt7461			+/-1C TDM Extended Temp Range I.C
 at,24c08		i2c serial eeprom  (24cxx)
 atmel,24c02		i2c serial eeprom  (24cxx)
 atmel,at97sc3204t	i2c trusted platform module (TPM)
+capella,cm32181		CM32181: Ambient Light Sensor
 catalyst,24c32		i2c serial eeprom
 dallas,ds1307		64 x 8, Serial, I2C Real-Time Clock
 dallas,ds1338		I2C RTC with 56-Byte NV RAM
diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index a022f27..d12b2a0 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -27,6 +27,17 @@ config APDS9300
 	 To compile this driver as a module, choose M here: the
 	 module will be called apds9300.
 
+config CM32181
+	depends on I2C
+	tristate "CM32181 driver"
+	help
+	 Say Y here if you use cm32181.
+	 This option enables ambient light sensor using
+	 Capella cm32181 device driver.
+
+	 To compile this driver as a module, choose M here:
+	 the module will be called cm32181.
+
 config CM36651
 	depends on I2C
 	tristate "CM36651 driver"
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index daa327f..60e35ac 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -5,6 +5,7 @@
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_APDS9300)		+= apds9300.o
+obj-$(CONFIG_CM32181)		+= cm32181.o
 obj-$(CONFIG_CM36651)		+= cm36651.o
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c
new file mode 100644
index 0000000..40cc394
--- /dev/null
+++ b/drivers/iio/light/cm32181.c
@@ -0,0 +1,380 @@
+/*
+ * Copyright (C) 2013 Capella Microsystems Inc.
+ * Author: Kevin Tsai <ktsai@capellamicro.com>
+ *
+ * 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/regulator/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+#include <linux/init.h>
+
+/* Registers Address */
+#define CM32181_REG_ADDR_CMD		0x00
+#define CM32181_REG_ADDR_ALS		0x04
+#define CM32181_REG_ADDR_STATUS		0x06
+#define CM32181_REG_ADDR_ID		0x07
+
+/* Number of Configurable Registers */
+#define CM32181_CONF_REG_NUM		0x01
+
+/* CMD register */
+#define CM32181_CMD_ALS_ENABLE		0x00
+#define CM32181_CMD_ALS_DISABLE		0x01
+#define CM32181_CMD_ALS_INT_EN		0x02
+
+#define CM32181_CMD_ALS_IT_SHIFT	6
+#define CM32181_CMD_ALS_IT_MASK		(0x0F << CM32181_CMD_ALS_IT_SHIFT)
+#define CM32181_CMD_ALS_IT_DEFAULT	(0x00 << CM32181_CMD_ALS_IT_SHIFT)
+
+#define CM32181_CMD_ALS_SM_SHIFT	11
+#define CM32181_CMD_ALS_SM_MASK		(0x03 << CM32181_CMD_ALS_SM_SHIFT)
+#define CM32181_CMD_ALS_SM_DEFAULT	(0x01 << CM32181_CMD_ALS_SM_SHIFT)
+
+#define CM32181_MLUX_PER_BIT		5	/* ALS_SM=01 IT=800ms */
+#define CM32181_MLUX_PER_BIT_BASE_IT	800000	/* Based on IT=800ms */
+#define	CM32181_CALIBSCALE_DEFAULT	1000
+#define CM32181_CALIBSCALE_RESOLUTION	1000
+#define MLUX_PER_LUX			1000
+
+static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = {
+	CM32181_REG_ADDR_CMD,
+};
+
+static const int als_it_bits[] = {12, 8, 0, 1, 2, 3};
+static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000,
+	800000};
+
+struct cm32181_chip {
+	struct i2c_client *client;
+	struct mutex lock;
+	u16 conf_regs[CM32181_CONF_REG_NUM];
+	int calibscale;
+};
+
+/**
+ * cm32181_reg_init() - Initialize CM32181 registers
+ * @cm32181:	pointer of struct cm32181.
+ *
+ * Initialize CM32181 ambient light sensor register to default values.
+ *
+ * Return: 0 for success; otherwise for error code.
+ */
+static int cm32181_reg_init(struct cm32181_chip *cm32181)
+{
+	struct i2c_client *client = cm32181->client;
+	int i;
+	s32 ret;
+
+	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID);
+	if (ret < 0)
+		return ret;
+
+	/* check device ID */
+	if ((ret & 0xFF) != 0x81)
+		return -ENODEV;
+
+	/* Default Values */
+	cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE |
+			CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT;
+	cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT;
+
+	/* Initialize registers*/
+	for (i = 0; i < CM32181_CONF_REG_NUM; i++) {
+		ret = i2c_smbus_write_word_data(client, cm32181_reg[i],
+			cm32181->conf_regs[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ *  cm32181_read_als_it() - Get sensor integration time (ms)
+ *  @cm32181:	pointer of struct cm32181
+ *  @val:	pointer of int to load the als_it value.
+ *
+ *  Report the current integartion time by millisecond.
+ *
+ *  Return: IIO_VAL_INT for success, otherwise -EINVAL.
+ */
+static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val)
+{
+	u16 als_it;
+	int i;
+
+	als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD];
+	als_it &= CM32181_CMD_ALS_IT_MASK;
+	als_it >>= CM32181_CMD_ALS_IT_SHIFT;
+	for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) {
+		if (als_it == als_it_bits[i]) {
+			*val = als_it_value[i];
+			return IIO_VAL_INT;
+		}
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * cm32181_write_als_it() - Write sensor integration time
+ * @cm32181:	pointer of struct cm32181.
+ * @val:	integration time by millisecond.
+ *
+ * Convert integration time (ms) to sensor value.
+ *
+ * Return: i2c_smbus_write_word_data command return value.
+ */
+static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val)
+{
+	struct i2c_client *client = cm32181->client;
+	u16 als_it;
+	int ret, i, n;
+
+	n = ARRAY_SIZE(als_it_value);
+	for (i = 0; i < n; i++)
+		if (val <= als_it_value[i])
+			break;
+	if (i >= n)
+		i = n - 1;
+
+	als_it = als_it_bits[i];
+	als_it <<= CM32181_CMD_ALS_IT_SHIFT;
+
+	mutex_lock(&cm32181->lock);
+	cm32181->conf_regs[CM32181_REG_ADDR_CMD] &=
+		~CM32181_CMD_ALS_IT_MASK;
+	cm32181->conf_regs[CM32181_REG_ADDR_CMD] |=
+		als_it;
+	ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD,
+			cm32181->conf_regs[CM32181_REG_ADDR_CMD]);
+	mutex_unlock(&cm32181->lock);
+
+	return ret;
+}
+
+/**
+ * cm32181_get_lux() - report current lux value
+ * @cm32181:	pointer of struct cm32181.
+ *
+ * Convert sensor raw data to lux.  It depends on integration
+ * time and claibscale variable.
+ *
+ * Return: Positive value is lux, otherwise is error code.
+ */
+static int cm32181_get_lux(struct cm32181_chip *cm32181)
+{
+	struct i2c_client *client = cm32181->client;
+	int ret;
+	int als_it;
+	unsigned long lux;
+
+	ret = cm32181_read_als_it(cm32181, &als_it);
+	if (ret < 0)
+		return -EINVAL;
+
+	lux = CM32181_MLUX_PER_BIT;
+	lux *= CM32181_MLUX_PER_BIT_BASE_IT;
+	lux /= als_it;
+
+	ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS);
+	if (ret < 0)
+		return ret;
+
+	lux *= ret;
+	lux *= cm32181->calibscale;
+	lux /= CM32181_CALIBSCALE_RESOLUTION;
+	lux /= MLUX_PER_LUX;
+
+	if (lux > 0xFFFF)
+		lux = 0xFFFF;
+
+	return lux;
+}
+
+static int cm32181_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		ret = cm32181_get_lux(cm32181);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*val = cm32181->calibscale;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_INT_TIME:
+		ret = cm32181_read_als_it(cm32181, val);
+		return ret;
+	}
+
+	return -EINVAL;
+}
+
+static int cm32181_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct cm32181_chip *cm32181 = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBSCALE:
+		cm32181->calibscale = val;
+		return val;
+	case IIO_CHAN_INFO_INT_TIME:
+		ret = cm32181_write_als_it(cm32181, val);
+		return ret;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * cm32181_get_it_available() - Get available ALS IT value
+ * @dev:	pointer of struct device.
+ * @attr:	pointer of struct device_attribute.
+ * @buf:	pointer of return string buffer.
+ *
+ * Display the available integration time values by millisecond.
+ *
+ * Return: string length.
+ */
+static ssize_t cm32181_get_it_available(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int i, n, len;
+
+	n = ARRAY_SIZE(als_it_value);
+	for (i = 0, len = 0; i < n; i++)
+		len += sprintf(buf + len, "%d ", als_it_value[i]);
+	return len + sprintf(buf + len, "\n");
+}
+
+static const struct iio_chan_spec cm32181_channels[] = {
+	{
+		.type = IIO_LIGHT,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_PROCESSED) |
+			BIT(IIO_CHAN_INFO_CALIBSCALE) |
+			BIT(IIO_CHAN_INFO_INT_TIME),
+	}
+};
+
+
+static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
+			S_IRUGO, cm32181_get_it_available, NULL, 0);
+
+static struct attribute *cm32181_attributes[] = {
+	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group cm32181_attribute_group = {
+	.attrs = cm32181_attributes
+};
+
+static const struct iio_info cm32181_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= &cm32181_read_raw,
+	.write_raw		= &cm32181_write_raw,
+	.attrs			= &cm32181_attribute_group,
+};
+
+static int cm32181_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct cm32181_chip *cm32181;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181));
+	if (!indio_dev) {
+		dev_err(&client->dev, "devm_iio_device_alloc failed\n");
+		return -ENOMEM;
+	}
+
+	cm32181 = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	cm32181->client = client;
+
+	mutex_init(&cm32181->lock);
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->channels = cm32181_channels;
+	indio_dev->num_channels = ARRAY_SIZE(cm32181_channels);
+	indio_dev->info = &cm32181_info;
+	indio_dev->name = id->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = cm32181_reg_init(cm32181);
+	if (ret) {
+		dev_err(&client->dev,
+			"%s: register init failed\n",
+			__func__);
+		return ret;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&client->dev,
+			"%s: regist device failed\n",
+			__func__);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int cm32181_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+	return 0;
+}
+
+static const struct i2c_device_id cm32181_id[] = {
+	{ "cm32181", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, cm32181_id);
+
+static const struct of_device_id cm32181_of_match[] = {
+	{ .compatible = "capella,cm32181" },
+	{ }
+};
+
+static struct i2c_driver cm32181_driver = {
+	.driver = {
+		.name	= "cm32181",
+		.of_match_table = of_match_ptr(cm32181_of_match),
+		.owner	= THIS_MODULE,
+	},
+	.id_table       = cm32181_id,
+	.probe		= cm32181_probe,
+	.remove		= cm32181_remove,
+};
+
+module_i2c_driver(cm32181_driver);
+
+MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>");
+MODULE_DESCRIPTION("CM32181 ambient light sensor driver");
+MODULE_LICENSE("GPL");
-- 
1.8.3.1

Re: [PATCH V4 1/1] iio: add Capella CM32181 ambient light sensor driver.

[Jonathan]

On 24/12/13 01:53, Kevin Tsai wrote:
> Add Capella Microsystem CM32181 Ambient Light Sensor IIO driver.
> This driver will convert raw data to lux value under open-air
> condition. Change the calibscale based on the cover material.
>
> Signed-off-by: Kevin Tsai <ktsai@capellamicro.com>
> ---
Hi Kevin,

It is good practice to list here (nothing from here goes in final commit
message) any changes since the previous version.  This just makes it clear
whether you have responded to all review comments, particularly when there
are multiple people reviewing the patch.


Other than that, I'm happy with this and have applied it to the togreg 
branch of iio.git - initially pushed out as testing for build tests.

Note I made one tiny white space change (dropped a blank line where 
there were two...