linux-kernel - [PATCH 2/5] max44000: Initial support for proximity reading

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Message-Id: <807fa69227e6745e73c207ca0b2af59255893bdb.1460045763.git.leonard.crestez@intel.com>
Date:	Thu,  7 Apr 2016 19:21:51 +0300
From:	Crestez Dan Leonard <leonard.crestez@...el.com>
To:	Jonathan Cameron <jic23@...nel.org>, linux-iio@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Hartmut Knaack <knaack.h@....de>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Peter Meerwald-Stadler <pmeerw@...erw.net>,
	Daniel Baluta <daniel.baluta@...el.com>,
	Crestez Dan Leonard <leonard.crestez@...el.com>
Subject: [PATCH 2/5] max44000: Initial support for proximity reading

The proximity sensor relies on sending pulses to an external IR led and
it is disabled by default on powerup. The driver will enable it with a
default power setting.

Signed-off-by: Crestez Dan Leonard <leonard.crestez@...el.com>
---
 drivers/iio/light/max44000.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
index 7c12153..10a0fe8 100644
--- a/drivers/iio/light/max44000.c
+++ b/drivers/iio/light/max44000.c
@@ -41,6 +41,23 @@
 #define MAX44000_REG_TRIM_GAIN_GREEN	0x0f
 #define MAX44000_REG_TRIM_GAIN_IR	0x10
 
+/* REG_CFG bits */
+#define MAX44000_CFG_ALSINTE		0x01
+#define MAX44000_CFG_PRXINTE		0x02
+#define MAX44000_CFG_MASK		0x1c
+#define MAX44000_CFG_MODE_SHUTDOWN	0x00
+#define MAX44000_CFG_MODE_ALS_GIR	0x04
+#define MAX44000_CFG_MODE_ALS_G		0x08
+#define MAX44000_CFG_MODE_ALS_IR	0x0c
+#define MAX44000_CFG_MODE_ALS_PRX	0x10
+#define MAX44000_CFG_MODE_PRX		0x14
+#define MAX44000_CFG_TRIM		0x20
+
+/* REG_TX bits */
+#define MAX44000_LED_CURRENT_MASK	0xf
+#define MAX44000_LED_CURRENT_MAX	11
+#define MAX44000_LED_CURRENT_DEFAULT	6
+
 #define MAX44000_ALSDATA_OVERFLOW	0x4000
 
 #define MAX44000_REGMASK_READABLE	0x419fff
@@ -60,6 +77,12 @@ static const struct iio_chan_spec max44000_channels[] = {
 	{
 		.type = IIO_LIGHT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
+					    BIT(IIO_CHAN_INFO_INT_TIME),
+	},
+	{
+		.type = IIO_PROXIMITY,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 	},
 };
@@ -90,11 +113,23 @@ static inline int max44000_read_alsval(struct max44000_data *data)
 	return regval;
 }
 
+static inline int max44000_write_led_current_raw(struct max44000_data *data, int val)
+{
+	/* Maybe we should clamp the value instead? */
+	if (val < 0 || val > MAX44000_LED_CURRENT_MAX)
+		return -ERANGE;
+	if (val >= 8)
+		val += 4;
+	return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX,
+				 MAX44000_LED_CURRENT_MASK, val);
+}
+
 static int max44000_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val, int *val2, long mask)
 {
 	struct max44000_data *data = iio_priv(indio_dev);
+	unsigned int regval;
 	int ret;
 
 	switch (mask) {
@@ -109,6 +144,15 @@ static int max44000_read_raw(struct iio_dev *indio_dev,
 			*val = ret;
 			return IIO_VAL_INT;
 
+		case IIO_PROXIMITY:
+			mutex_lock(&data->lock);
+			ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, &regval);
+			mutex_unlock(&data->lock);
+			if (ret < 0)
+				return ret;
+			*val = regval;
+			return IIO_VAL_INT;
+
 		default:
 			return -EINVAL;
 		}
@@ -244,6 +288,23 @@ static int max44000_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	/* By default the LED pulse used for the proximity sensor is disabled.
+	 * Set a middle value so that we get some sort of valid data by default.
+	 */
+	ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "failed to write init config: %d\n", ret);
+		return ret;
+	}
+
+	/* By default set in ALS_PRX mode which allows easy reading of both values. */
+	reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX;
+	ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "failed to write init config: %d\n", ret);
+		return ret;
+	}
+
 	return iio_device_register(indio_dev);
 }
 
-- 
2.8.0.rc3