Date:	Fri, 14 Aug 2015 12:29:39 +0300
From:	Adriana Reus <adriana.reus@...el.com>
To:	jic23@...nel.org, pmeerw@...erw.net, daniel.baluta@...el.com
Cc:	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, Adriana Reus <adriana.reus@...el.com>
Subject: [PATCH v3 1/2] 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@...el.com>
---
Changes since v2:
 - Adressed Peter's comments (with the exception of setting
   the ths_vals array as const - if I do that the compiler will
   eventually whine because it gets passed as an argument to device_property_read).
 - Tried to break down the compound register values into more intuitive definitions.
 - Eliminated the read helper functions.

 drivers/iio/light/Kconfig   |  10 +
 drivers/iio/light/Makefile  |   1 +
 drivers/iio/light/us5182d.c | 484 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 495 insertions(+)
 create mode 100644 drivers/iio/light/us5182d.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 7ed859a..0442f01 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -287,6 +287,16 @@ 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 91c74c0..528cc8f 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -27,4 +27,5 @@ 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 0000000..9ba99f5
--- /dev/null
+++ b/drivers/iio/light/us5182d.c
@@ -0,0 +1,484 @@
+/*
+ * 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_REG_CFG1				0x01
+#define US5182D_REG_CFG2				0x02
+#define US5182D_REG_CFG3				0x03
+#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_ONESHOT_EN			BIT(6)
+#define US5182D_SHUTDOWN_EN			BIT(7)
+#define US5182D_OPMODE_ALS			0x01
+#define US5182D_OPMODE_PX			0x02
+#define US5182D_OPMODE_SHIFT			4
+#define US5182D_WORD_ENABLE			BIT(0)
+#define US5182D_ALS_RES16			BIT(4)
+#define US5182D_PX_RES16			BIT(4)
+#define US5182D_PXGAIN_DEFAULT			BIT(2)
+#define US5182D_LED_CURRENT100			(BIT(4) | BIT(5))
+
+#define US5182D_REG_CFG0_DEFAULT \
+	(US5182D_SHUTDOWN_EN | US5182D_WORD_ENABLE)
+#define US5182D_REG_CFG1_DEFAULT		US5182D_ALS_RES16
+#define US5182D_REG_CFG2_DEFAULT \
+	(US5182D_PX_RES16 | US5182D_PXGAIN_DEFAULT)
+#define US5182D_REG_CFG3_DEFAULT		US5182D_LED_CURRENT100
+#define US5182D_REG_CFG4_DEFAULT		0x00
+
+#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 th's 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;
+	/* protect opmode */
+	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_REG_CFG0_DEFAULT},
+	{US5182D_REG_CFG1, US5182D_REG_CFG1_DEFAULT},
+	{US5182D_REG_CFG2, US5182D_REG_CFG2_DEFAULT},
+	{US5182D_REG_CFG3, US5182D_REG_CFG3_DEFAULT},
+	{US5182D_REG_MODE_STORE, US5182D_STORE_MODE},
+	{US5182D_REG_CFG4, US5182D_REG_CFG4_DEFAULT},
+};
+
+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;
+
+	ret = ret | US5182D_ONESHOT_EN;
+
+	/* update mode */
+	ret = ret & ~US5182D_OPMODE_MASK;
+	ret = ret | (mode << US5182D_OPMODE_SHIFT);
+
+	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG0, ret);
+	if (ret < 0)
+		return ret;
+
+	if (mode == data->opmode)
+		return 0;
+
+	data->opmode = mode;
+	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_MODE_STORE,
+					US5182D_STORE_MODE);
+	if (ret < 0)
+		return ret;
+	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;
+		ret = (ret & US5182D_AGAIN_MASK);
+		*val2 = us5182d_scales[ret];
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+out_err:
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static int us5182d_update_dark_th(struct us5182d_data *data, int index)
+{
+	__be16 dark_th = cpu_to_be16(data->us5182d_dark_ths[index]);
+	u8 *bytes = (u8 *)&dark_th;
+	int ret;
+
+	/* Registers Dark_Th (0x27 0x28) don't work in word mode accessing */
+	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_UDARK_TH,
+					bytes[0]);
+	if (ret < 0)
+		return ret;
+
+	return i2c_smbus_write_byte_data(data->client, US5182D_REG_UDARK_TH + 1,
+					bytes[1]);
+}
+
+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);
+	u8 index = US5182D_REG_CFG1_DEFAULT & US5182D_AGAIN_MASK;
+	int ret;
+
+	ret = us5182d_update_dark_th(data, index);
+	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_REG_CFG0_DEFAULT);
+}
+
+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@...el.com>");
+MODULE_DESCRIPTION("Driver for us5182d Proximity and Light Sensor");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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