[PATCH v2 0/1] iio:light: Add support for APDS9930 ALS and proximity

[PATCH v2 0/1] iio:light: Add support for APDS9930 ALS and proximity

[Cristina Ciocan]

Hello,

This patch adds support for APDS9930. I am not sure about integrating it with
APDS9300 which is similar, I am waiting for reviews and if that is the case, I
shall integrate it in the next patch set.

I kept the threshold changing in the driver because I also adapt the ALS gain,
which leads to different values on the CH0 channel under the same light
conditions, thus the thresholds need adapting as well. The userspace can only
read these thresholds from sysfs, not change them.

Changes since v1:
	- ALS code cleanup
	- added proximity support

Cristina Ciocan (1):
  iio:light: Avago APDS9930 ALS and proximity sensor

 drivers/iio/light/Kconfig    |   10 +
 drivers/iio/light/Makefile   |    1 +
 drivers/iio/light/apds9930.c | 1097 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1108 insertions(+)
 create mode 100644 drivers/iio/light/apds9930.c

--
1.8.1.2

[PATCH v2 1/1] iio:light: Avago APDS9930 ALS and proximity sensor

[Cristina Ciocan]

Added IIO driver for Avago's APDS9930 ALS and proximity sensor.

It offers ACPI/DT support, irq and event handling, raw readings for both ALS and
proximity.

Datasheet for this device can be found at:
	http://www.avagotech.com/docs/AV02-3190EN

Signed-off-by: Cristina Ciocan <cristina.ciocan@intel.com>
---
 drivers/iio/light/Kconfig    |   10 +
 drivers/iio/light/Makefile   |    1 +
 drivers/iio/light/apds9930.c | 1097 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1108 insertions(+)
 create mode 100644 drivers/iio/light/apds9930.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 01a1a16..f5fa235 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -37,6 +37,16 @@ config APDS9300
 	 To compile this driver as a module, choose M here: the
 	 module will be called apds9300.

+config APDS9930
+	tristate "APDS9930 ambient light and proximity sensor"
+	depends on I2C
+	help
+	 Say Y here if you want to build a driver for the Avago APDS9930
+	 ambient light and proximity sensor.
+
+	 To compile this driver as a module, choose M here: the
+	 module will be called apds9930.
+
 config CM32181
 	depends on I2C
 	tristate "CM32181 driver"
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index ad7c30f..535d289 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -6,6 +6,7 @@
 obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
 obj-$(CONFIG_AL3320A)		+= al3320a.o
 obj-$(CONFIG_APDS9300)		+= apds9300.o
+obj-$(CONFIG_APDS9930)		+= apds9930.o
 obj-$(CONFIG_CM32181)		+= cm32181.o
 obj-$(CONFIG_CM3232)		+= cm3232.o
 obj-$(CONFIG_CM3323)		+= cm3323.o
diff --git a/drivers/iio/light/apds9930.c b/drivers/iio/light/apds9930.c
new file mode 100644
index 0000000..fa5fb51
--- /dev/null
+++ b/drivers/iio/light/apds9930.c
@@ -0,0 +1,1097 @@
+/*
+ * This is a driver for Avago APDS9930 ALS and proxmity sensor chip. It
+ * is inspired from drivers/iio/misc/apds990x.c to use IIO.
+ *
+ * The I2C slave address for this device is 0x39.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * TODO: runtime pm support
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/pm.h>
+#include <linux/mutex.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/property.h>
+#include <linux/bitops.h>
+
+#include <linux/iio/types.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/events.h>
+
+#include <linux/gpio/consumer.h>
+
+#define APDS9930_DRIVER_NAME	"apds9930"
+#define APDS9930_IRQ_NAME	"apds9930_irq"
+#define APDS9930_GPIO_NAME	"apds9930_gpio"
+
+#define APDS9930_INIT_SLEEP	5 /* sleep for 5 ms before issuing commands */
+
+/* Register set (rw = read/write, r = read, w = write) */
+#define APDS9930_ENABLE_REG	0x00	/* rw-Enable of states and interrupts */
+#define APDS9930_ATIME_REG	0x01	/* rw-ALS ADC time*/
+#define APDS9930_PTIME_REG	0x02	/* rw-Proximity ADC time */
+#define APDS9930_WTIME_REG	0x03	/* rw-Wait time */
+#define APDS9930_AILTL_REG	0x04	/* rw-ALS interrupt low threshold low
+					 * byte
+					 */
+#define APDS9930_AIHTL_REG	0x06	/* rw-ALS interrupt high threshold low
+					 * byte
+					 */
+#define APDS9930_PILTL_REG	0x08	/* rw-Proximity interrupt low threshold
+					 * low byte
+					 */
+#define APDS9930_PIHTL_REG	0x0A	/* rw-Proximity interrupt high threshold
+					 * low byte
+					 */
+#define APDS9930_PERS_REG	0x0C	/* rw-Interrupt persistence filters */
+#define APDS9930_CONFIG_REG	0x0D	/* rw-Configuration */
+#define APDS9930_PPULSE_REG	0x0E	/* rw-Proximity pulse control */
+#define APDS9930_CONTROL_REG	0x0F	/* rw-Gain control register */
+#define APDS9930_ID_REG		0x12	/* r-Device ID */
+#define APDS9930_STATUS_REG	0x13	/* r-Device status */
+#define APDS9930_CDATAL_REG	0x14	/* r-Ch0 ADC low data register */
+#define APDS9930_CDATAH_REG	0x15	/* r-Ch0 ADC high data register */
+#define APDS9930_IRDATAL_REG	0x16	/* r-Ch1 ADC low data register */
+#define APDS9930_IRDATAH_REG	0x17	/* r-Ch1 ADC high data register */
+#define APDS9930_PDATAL_REG	0x18	/* r-Proximity ADC low data register */
+#define APDS9930_POFFSET_REG	0x1E	/* rw-Proximity offset register */
+
+/* Useful bits per register */
+
+/* Enable register */
+#define APDS9930_SAI	BIT(6)	/* Sleep after interrupt */
+#define APDS9930_PIEN	BIT(5)	/* Proximity interrupt enable */
+#define APDS9930_AIEN	BIT(4)	/* ALS interrupt enable */
+#define APDS9930_WEN	BIT(3)	/* Wait enable */
+#define APDS9930_PEN	BIT(2)	/* Proximity enable */
+#define APDS9930_AEN	BIT(1)	/* ALS enable */
+#define APDS9930_PON	BIT(0)	/* Power ON */
+
+/* Persistence register */
+#define APDS9930_PPERS_SHIFT	4	/* Proximity interrupt persistence */
+#define APDS9930_APERS_SHIFT	0	/* Interrupt persistence */
+
+/* Configuration register */
+#define APDS9930_AGL_SHIFT	2	/* ALS gain level */
+#define APDS9930_WLONG_SHIFT	1	/* Wait long */
+#define APDS9930_PDL_SHIFT	0	/* Proximity drive level */
+
+/* Control register */
+#define APDS9930_PDRIVE_SHIFT	6	/* LED drive strength */
+#define APDS9930_PDIODE_SHIFT	4	/* Proximity diode select */
+#define APDS9930_PGAIN_SHIFT	2	/* Proximity gain control */
+#define APDS9930_AGAIN_SHIFT	0	/* ALS gain control */
+
+/* Device ID - possible values */
+#define APDS9930_ID	0x39
+
+/* Status register */
+#define APDS9930_PSAT	BIT(6)	/* Proximity saturation */
+#define APDS9930_PINT	BIT(5)	/* Proximity interrupt */
+#define APDS9930_AINT	BIT(4)	/* ALS interrupt */
+#define APDS9930_PVALID	BIT(1)	/* PS valid */
+#define APDS9930_AVALID	BIT(0)	/* ALS valid */
+
+/* I2C command register - fields and possible field values */
+#define APDS9930_CMD_TYPE_SHIFT		5
+#define APDS9930_CMD_ADDR_SHIFT		0
+/* CMD bit value must be set to 1 when addressing command register */
+#define APDS9930_CMD_SELECT		0x80
+/* TYPE possible values */
+#define APDS9930_CMD_TYPE_RB		0		/* Repeated byte */
+#define APDS9930_CMD_TYPE_AUTO_INC	BIT(5)		/* Auto-increment */
+#define APDS9930_CMD_TYPE_SPECIAL_FUNC	GENMASK(6, 5)	/* Special function */
+/* ADDR possible values */
+#define APDS9930_CMD_TYPE_NONE		0x0	/* Normal - no action */
+#define APDS9930_CMD_TYPE_PS		0x5	/* Proximity interrupt clear */
+#define APDS9930_CMD_TYPE_ALS		0x6	/* ALS interrupt clear */
+#define APDS9930_CMD_TYPE_BOTH		0x7	/* Both interrupt clear */
+/* Clear masks */
+#define APDS9930_CLEAR_CMD_TYPE_MASK	~(0x7 << APDS9930_CMD_TYPE_SHIFT)
+/* Shortcut to clear and set CMD and TYPE fields */
+#define APDS9930_CMD_REG_SETUP(reg, transaction_type) {		\
+	reg &= APDS9930_CLEAR_CMD_TYPE_MASK;		\
+	reg |= APDS9930_CMD_SELECT | transaction_type;	\
+}
+
+/* Default values for registers content */
+#define APDS9930_DISABLE_ALL	0	/* Disable and powerdown */
+#define APDS9930_ENABLE_ALL	0x37	/* Set all ALS & PS bits and power on */
+#define APDS9930_DEF_ATIME	0xdb	/* 50 ms - ALSIT value in order to
+					 * reject 50/60 Hz ripple; if higher
+					 * resolution is needed, increase ALSIT
+					 * with mutiples of 50
+					 */
+#define APDS9930_DEF_PTIME	0xff	/* 2.7 ms - min prox integration time */
+#define APDS9930_DEF_WTIME	0xff	/* 2.7 ms - min wait time */
+#define APDS9930_DEF_PPULSE	8	/* Min prox pulse count */
+#define APDS9930_DEF_PDRIVE	0	/* 100 mA of LED power */
+#define APDS9930_DEF_PDIODE	2	/* Ch1 diode (shifted value) */
+#define APDS9930_DEF_PGAIN	2	/* 4 x proximity gain */
+#define APDS9930_DEF_AGAIN	2	/* 16 x ALS gain */
+#define APDS9930_DEF_WEN	8	/* Enable wait */
+#define APDS9930_DEF_PEN	4	/* Enable proximity */
+#define APDS9930_DEF_AEN	2	/* Enable ALS */
+#define APDS9930_DEF_PON	1	/* Power ON */
+#define APDS9930_DEF_APERS	3	/* Consecutive exceeding threshold
+					 * cycles to trigger ALS interrupt
+					 */
+#define APDS9930_DEF_PPERS	3	/* Consecutive PS execeeding threshold
+					 * cycles to trigger PS interrupt
+					 */
+
+/* Interrupt threshold defaults - setting low to maximum will trigger a first
+ * interrupt to allow us to read the data registers status and properly set a
+ * threshold value to match the current environment.
+ *
+ * The default high threshold is set only for consistency, since the registers
+ * are checked against in order: first if the value of CDATA/PDATA is above LOW;
+ * if so, trigger interrupt and do not check the HIGH threshold.
+ */
+#define APDS9930_DEF_ALS_THRESH_LOW	0xffff
+#define APDS9930_DEF_ALS_THRESH_HIGH	0x0
+#define APDS9930_DEF_PS_THRESH_LOW	1023
+#define APDS9930_DEF_PS_THRESH_HIGH	0
+
+#define APDS9930_MIN_PS_THRESH		0	/* No object near the sensor */
+#define APDS9930_MAX_PS_THRESH		1023	/* Object in close proximity */
+#define APDS9930_DETECTION_PS_THRESH	600	/* Object detected near-by */
+
+/* Default, open air, coefficients (for Lux computation) */
+#define APDS9930_DEF_DF	52	/* Device factor */
+/* Material-depending coefficients (set to open air values). They are scaled for
+ * computation purposes by 100 (as stored in APDS9930_COEF_SCALE).
+ */
+#define APDS9930_DEF_LUX_DIVISION_SCALE	10000
+#define APDS9930_DEF_GA			49
+#define APDS9930_DEF_B			186
+#define APDS9930_DEF_C			74
+#define APDS9930_DEF_D			129
+#define APDS9930_COEF_SCALE		100
+
+/* Possible ALS gain values (with AGL cleared) */
+static const int apds9930_again_values[] = {1, 8, 16, 120};
+#define APDS9930_MAX_AGAIN_INDEX	3
+#define APDS9930_AGL_DIVISION_SCALE	6
+
+/* Percentages from the maximum CH0 value that indicate the recorded CH0 data is
+ * too low or too high - for AGAIN adapting purposes.
+ */
+#define APDS9930_CH0_HIGH_PERCENTAGE	90
+#define APDS9930_CH0_LOW_PERCENTAGE	10
+
+/* With how much (in percentages) must the CH0 value differ from one step to
+ * another in order to consider a significant change in light.
+ */
+#define APDS9930_ALS_HYSTERESIS		20
+
+/* DT or ACPI device properties names */
+#define APDS9930_GA_PROP	"intel,ga"
+#define APDS9930_COEF_B_PROP	"intel,coeff-B"
+#define APDS9930_COEF_C_PROP	"intel,coeff-C"
+#define APDS9930_COEF_D_PROP	"intel,coeff-D"
+#define APDS9930_DF_PROP	"intel,df"
+#define APDS9930_AGAIN_PROP	"intel,als-gain"
+#define APDS9930_ATIME_PROP	"intel,atime"
+#define APDS9930_PDRIVE_PROP	"intel,pdrive"
+#define APDS9930_PPULSE_PROP	"intel,ppcount"
+
+struct apds9930_coefficients {
+	/* GA, B, C and D coefficients are scaled by 100 for computational
+	 * purposes
+	 */
+	int ga;
+	/* This is 1, but needs to be set to a scaled value, thus if
+	 * we decide to change the scale, this coefficient must also
+	 * be changed.
+	 */
+	int coef_a;
+	int coef_b;
+	int coef_c;
+	int coef_d;
+	int df;
+};
+
+struct apds9930_platform_data {
+	/* Glass-influenced factors */
+	struct apds9930_coefficients coefs;
+
+	/* ALS platform data */
+	u8 again;	/* AGAIN value (index in apds9930_again_values[]) */
+	u8 atime;	/* ALS integration time */
+
+	/* Proximity platform data */
+	u8 pdrive;
+	u8 ppulse;
+};
+
+struct apds9930_threshold {
+	u16 low;
+	u16 high;
+};
+
+struct apds9930_data {
+	struct i2c_client	*client;
+
+	/* Protect access to device data */
+	struct mutex		mutex;
+
+	/* Platform specific data */
+	struct apds9930_platform_data	platform_data;
+
+#define __coefs		platform_data.coefs
+#define __again		platform_data.again
+#define __atime		platform_data.atime
+#define __pdrive	platform_data.pdrive
+#define __ppulse	platform_data.ppulse
+
+	u8	alsit;
+	u16	ch0_max;		/* Maximum possible Ch0 data value */
+	bool	agl_enabled;
+
+	bool	als_intr_state;
+	bool	ps_intr_state;
+	struct apds9930_threshold	als_thresh;
+	struct apds9930_threshold	ps_thresh;
+};
+
+/* Writes data to the register; the next i2c_write call will write to the same
+ * register
+ */
+static inline int apds9930_write_byte(struct i2c_client *client, u8 reg,
+				      u8 data)
+{
+	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_RB);
+
+	return i2c_smbus_write_byte_data(client, reg, data);
+}
+
+/* Reads data from a register; the next i2c_read call will read from the same
+ * address
+ */
+static inline int apds9930_read_byte(struct i2c_client *client, u8 reg,
+				     u8 *data)
+{
+	int ret;
+
+	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_RB);
+	ret	= i2c_smbus_read_byte_data(client, reg);
+	*data	= ret;
+
+	return ret;
+}
+
+/* Writes 2 bytes at the given address */
+static inline int apds9930_write_word(struct i2c_client *client, u8 reg,
+				      u16 data)
+{
+	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_AUTO_INC);
+
+	return i2c_smbus_write_word_data(client, reg, data);
+}
+
+/* Reads 2 bytes from the given address */
+static inline int apds9930_read_word(struct i2c_client *client, u8 reg,
+				     u16 *data)
+{
+	int ret;
+
+	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_AUTO_INC);
+	ret	= i2c_smbus_read_word_data(client, reg);
+	*data	= ret;
+
+	return ret;
+}
+
+/* ALSIT = 2.73ms * (256 - ATIME), 2.73 = 5591/(2^11) */
+static inline u8 apds9930_atime_to_alsit(u8 atime_val)
+{
+	return (u8)(((256 - (u32)atime_val) * 5591) >> 11);
+}
+
+/* ATIME = 256 - ALSIT/2.73ms, 1/2.73 = 375/(2^10) */
+static inline u8 apds9930_alsit_to_atime(u8 alsit_val)
+{
+	return (u8)(256 - (((u32)alsit_val * 375) >> 10));
+}
+
+/* Computes maximum Ch0 data when atime is the given one. */
+static inline u16 apds9930_compute_max_ch0(u8 atime_val)
+{
+	return 1024 * (256 - (u32)atime_val) - 1;
+}
+
+/* Computes the ALS gain value for the next step and updates the current one */
+static void apds9930_update_again(struct apds9930_data *data, u16 ch0)
+{
+	int current_index, next_index, err;
+
+	/* Compute the value for the next measurement */
+	current_index	= data->__again;
+	next_index	= data->__again;
+
+	/* CH0 data too high, try to lower the ALS gain if possible */
+	if (ch0 >= (data->ch0_max * APDS9930_CH0_HIGH_PERCENTAGE) / 100) {
+		if (next_index == 0 && !(data->agl_enabled)) {
+			err = apds9930_write_byte(
+						  data->client,
+						  APDS9930_CONFIG_REG,
+						  1 << APDS9930_AGL_SHIFT);
+			if (!err)
+				data->agl_enabled = true;
+		} else if (next_index > 0) {
+			next_index--;
+		}
+	}
+
+	/* CH0 data too low, try to increase the ALS gain if possible */
+	else if (ch0 <= (data->ch0_max * APDS9930_CH0_LOW_PERCENTAGE) / 100) {
+		if (data->agl_enabled) {
+			err = apds9930_write_byte(data->client,
+						  APDS9930_CONFIG_REG,
+						  0);
+			if (!err)
+				data->agl_enabled = false;
+		} else if (next_index < APDS9930_MAX_AGAIN_INDEX) {
+			next_index++;
+		}
+	}
+
+	if (next_index != current_index) {
+		/* Update data's index value */
+		data->__again = next_index;
+
+		/* Update AGAIN for the next reading */
+		apds9930_write_byte(
+				data->client,
+				APDS9930_CONTROL_REG,
+				data->__again << APDS9930_AGAIN_SHIFT |
+				APDS9930_DEF_PGAIN << APDS9930_PGAIN_SHIFT |
+				APDS9930_DEF_PDIODE << APDS9930_PDIODE_SHIFT |
+				data->__pdrive << APDS9930_PDRIVE_SHIFT);
+	}
+}
+
+/* Update thresholds so as to generate interrupts when the CH0 data changes
+ * significantly since the last update; significantly is quantified by the
+ * hysteresis factor: if the ALS state changes with more than hysteresis %,
+ * update the thresholds.
+ */
+static void apds9930_update_als_thresholds(struct apds9930_data *data, u16 ch0)
+{
+	data->als_thresh.low	= (ch0 * (100 - APDS9930_ALS_HYSTERESIS)) / 100;
+	data->als_thresh.high	= min((ch0 *
+				       (100 + APDS9930_ALS_HYSTERESIS)) / 100,
+				      data->ch0_max);
+
+	apds9930_write_word(data->client, APDS9930_AILTL_REG,
+			    data->als_thresh.low);
+	apds9930_write_word(data->client, APDS9930_AIHTL_REG,
+			    data->als_thresh.high);
+}
+
+static void apds9930_update_ps_thresholds(struct apds9930_data *data, u16 ps)
+{
+	if (ps <= data->ps_thresh.low) {
+		/* Near to far => set limits to detect when it comes close */
+		data->ps_thresh.low	= APDS9930_MIN_PS_THRESH;
+		data->ps_thresh.high	= APDS9930_DETECTION_PS_THRESH;
+	} else if (ps >= data->ps_thresh.high) {
+		/* Far to near => set limits to detect when it goes further */
+		data->ps_thresh.low	= APDS9930_DETECTION_PS_THRESH;
+		data->ps_thresh.high	= APDS9930_MAX_PS_THRESH;
+	}
+
+	/* Update thresholds */
+	apds9930_write_word(data->client, APDS9930_PILTL_REG,
+			    data->ps_thresh.low);
+	apds9930_write_word(data->client, APDS9930_PIHTL_REG,
+			    data->ps_thresh.high);
+}
+
+/* Having the channel 0 and channels 1's data, compute the Lux value */
+static int apds9930_compute_lux(struct apds9930_data *data, u16 ch0, u16 ch1)
+{
+	long int iac1, iac2, alsit_val, again_val, tmp_iac;
+	unsigned long int iac, lux;
+	struct apds9930_coefficients cf;
+
+	/* Lux equation */
+	cf		= data->__coefs;
+	iac1		= cf.coef_a * ch0 - cf.coef_b * ch1;
+	iac2		= cf.coef_c * ch0 - cf.coef_d * ch1;
+	tmp_iac         = max(iac1, iac2);
+	iac             = (tmp_iac < 0) ? 0 : (unsigned long)tmp_iac;
+	alsit_val	= (int)(data->alsit);
+	again_val	= apds9930_again_values[data->__again];
+	lux		= (iac * cf.ga * cf.df) /
+				(alsit_val * again_val *
+				 APDS9930_DEF_LUX_DIVISION_SCALE);
+
+	return data->agl_enabled ? (APDS9930_AGL_DIVISION_SCALE * lux) : lux;
+}
+
+static int apds9930_enable_all(struct apds9930_data *data)
+{
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = apds9930_write_byte(data->client, APDS9930_ENABLE_REG,
+				  APDS9930_ENABLE_ALL);
+	if (ret < 0)
+		goto err;
+
+	data->als_intr_state	= true;
+	data->ps_intr_state	= true;
+err:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int apds9930_disable_all(struct apds9930_data *data)
+{
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = apds9930_write_byte(data->client, APDS9930_ENABLE_REG,
+				  APDS9930_DISABLE_ALL);
+	if (ret < 0)
+		goto err;
+
+	data->als_intr_state	= false;
+	data->ps_intr_state	= false;
+err:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int apds9930_chip_detect(struct apds9930_data *data)
+{
+	int ret;
+	u8 id;
+
+	ret = apds9930_read_byte(data->client, APDS9930_ID_REG, &id);
+	if (ret < 0)
+		return ret;
+
+	if (id != APDS9930_ID)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+/* Set the coefficients to those specified in properties if they exist,
+ * otherwise to default values.
+ */
+static void apds9930_set_platform_data(struct apds9930_data *data)
+{
+	struct apds9930_platform_data *pdata = data->client->dev.platform_data;
+	struct apds9930_coefficients defaults = {
+		.ga	= APDS9930_DEF_GA,
+		.coef_a	= APDS9930_COEF_SCALE,
+		.coef_b	= APDS9930_DEF_B,
+		.coef_c	= APDS9930_DEF_C,
+		.coef_d	= APDS9930_DEF_D,
+		.df	= APDS9930_DEF_DF,
+	};
+	struct device *dev = &data->client->dev;
+
+	/* Look for platform data */
+	if (pdata) {
+		data->__again	= pdata->again;
+		data->__atime	= pdata->atime;
+		data->__pdrive	= pdata->pdrive;
+		data->__ppulse	= pdata->ppulse;
+
+		if (pdata->coefs.ga == 0)
+			data->__coefs = defaults;
+		else
+			data->__coefs = pdata->coefs;
+
+		return;
+	}
+
+	/* Look for device properties and set them to proper value or to
+	 * default. */
+	if (device_property_read_u32(dev, APDS9930_GA_PROP, &data->__coefs.ga))
+		data->__coefs.ga = defaults.ga;
+
+	if (device_property_read_u32(dev, APDS9930_DF_PROP, &data->__coefs.df))
+		data->__coefs.df = defaults.df;
+
+	if (device_property_read_u32(dev, APDS9930_COEF_B_PROP,
+				     &data->__coefs.coef_b) ||
+	    device_property_read_u32(dev, APDS9930_COEF_C_PROP,
+				     &data->__coefs.coef_c) ||
+	    device_property_read_u32(dev, APDS9930_COEF_D_PROP,
+				     &data->__coefs.coef_d)) {
+		data->__coefs.coef_b	= defaults.coef_b;
+		data->__coefs.coef_c	= defaults.coef_c;
+		data->__coefs.coef_d	= defaults.coef_d;
+	}
+	data->__coefs.coef_a = defaults.coef_a;
+
+	if (device_property_read_u8(dev, APDS9930_ATIME_PROP, &data->__atime))
+		data->__atime = APDS9930_DEF_ATIME;
+
+	if (device_property_read_u8(dev, APDS9930_AGAIN_PROP, &data->__again))
+		data->__again = APDS9930_DEF_AGAIN;
+
+	/* We expect for the AGAIN value to be the one in the register (0, 1, 2
+	 * or 3). If we do find device property AGAIN, but is not valid, fall
+	 * back to the default one.
+	 */
+	if (data->__again > APDS9930_MAX_AGAIN_INDEX)
+		data->__again = APDS9930_DEF_AGAIN;
+
+	if (device_property_read_u8(dev, APDS9930_PDRIVE_PROP, &data->__pdrive))
+		data->__pdrive = APDS9930_DEF_PDRIVE;
+
+	if (device_property_read_u8(dev, APDS9930_PPULSE_PROP, &data->__ppulse))
+		data->__ppulse = APDS9930_DEF_PPULSE;
+}
+
+static void apds9930_chip_data_init(struct apds9930_data *data)
+{
+	apds9930_set_platform_data(data);
+
+	/* Init data to default values */
+	data->alsit		= apds9930_atime_to_alsit(data->__atime);
+	data->ch0_max		= apds9930_compute_max_ch0(APDS9930_DEF_ATIME);
+	data->agl_enabled	= false;
+	data->als_intr_state	= false;
+	data->ps_intr_state	= false;
+	data->als_thresh.low	= APDS9930_DEF_ALS_THRESH_LOW;
+	data->als_thresh.high	= APDS9930_DEF_ALS_THRESH_HIGH;
+	data->ps_thresh.low	= APDS9930_DEF_PS_THRESH_LOW;
+	data->ps_thresh.high	= APDS9930_DEF_PS_THRESH_HIGH;
+}
+
+/* Basic chip initialization, as described in the datasheet */
+static int apds9930_chip_registers_init(struct apds9930_data *data)
+{
+	struct i2c_client *client = data->client;
+	int ret;
+
+	/* Set timing registers default values (minimum) */
+	ret = apds9930_write_byte(client, APDS9930_ATIME_REG, (data->__atime));
+	if (ret < 0)
+		return ret;
+
+	ret = apds9930_write_byte(client, APDS9930_PTIME_REG,
+				  APDS9930_DEF_PTIME);
+	if (ret < 0)
+		return ret;
+	ret = apds9930_write_byte(client, APDS9930_WTIME_REG,
+				  APDS9930_DEF_WTIME);
+	if (ret < 0)
+		return ret;
+
+	/* Interrupt threshold default settings */
+	ret = apds9930_write_word(client, APDS9930_AILTL_REG,
+				  APDS9930_DEF_ALS_THRESH_LOW);
+	if (ret < 0)
+		return ret;
+	ret = apds9930_write_word(client, APDS9930_AIHTL_REG,
+				  APDS9930_DEF_ALS_THRESH_HIGH);
+	if (ret < 0)
+		return ret;
+	ret = apds9930_write_word(client, APDS9930_PILTL_REG,
+				  APDS9930_DEF_PS_THRESH_LOW);
+	if (ret < 0)
+		return ret;
+	ret = apds9930_write_word(client, APDS9930_PIHTL_REG,
+				  APDS9930_DEF_PS_THRESH_HIGH);
+	if (ret < 0)
+		return ret;
+
+	/* Set persistence filters to default values */
+	ret = apds9930_write_byte(client, APDS9930_PERS_REG,
+				  APDS9930_DEF_APERS << APDS9930_APERS_SHIFT |
+				  APDS9930_DEF_PPERS << APDS9930_PPERS_SHIFT);
+	if (ret < 0)
+		return ret;
+
+	/* Reset the configuration register (do not wait long) */
+	ret = apds9930_write_byte(client, APDS9930_CONFIG_REG, 0);
+	if (ret < 0)
+		return ret;
+
+	/* Set proximity pulse count register (number of pulses to be generated
+	 * during the proximity accum state)
+	 */
+	ret = apds9930_write_byte(client, APDS9930_PPULSE_REG, data->__ppulse);
+	if (ret < 0)
+		return ret;
+
+	/* Gain selection setting */
+	return apds9930_write_byte(
+				client, APDS9930_CONTROL_REG,
+				data->__again << APDS9930_AGAIN_SHIFT |
+				APDS9930_DEF_PGAIN << APDS9930_PGAIN_SHIFT |
+				APDS9930_DEF_PDIODE << APDS9930_PDIODE_SHIFT |
+				data->__pdrive << APDS9930_PDRIVE_SHIFT);
+}
+
+static int apds9930_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int *val,
+			     int *val2, long mask)
+{
+	struct apds9930_data *data	= iio_priv(indio_dev);
+	struct i2c_client *client	= data->client;
+	int ret;
+	u16 ch0, ch1, ch;
+
+	mutex_lock(&data->mutex);
+	switch (chan->type) {
+	case IIO_LIGHT:
+		/* Get Lux value */
+		ret = apds9930_read_word(client, APDS9930_CDATAL_REG, &ch0);
+		if (ret < 0)
+			break;
+		ret = apds9930_read_word(client, APDS9930_IRDATAL_REG, &ch1);
+		if (ret < 0)
+			break;
+
+		/* Compute Lux value and check its validity */
+		*val = apds9930_compute_lux(data, ch0, ch1);
+		apds9930_update_again(data, ch0);
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_INTENSITY:
+		/* Get ch0 or ch1 raw value */
+		ret = apds9930_read_word(client, chan->channel ?
+					 APDS9930_IRDATAL_REG :
+					 APDS9930_CDATAL_REG,
+					 &ch);
+		if (ret < 0)
+			break;
+
+		*val	= (int)ch;
+		ret	= IIO_VAL_INT;
+		break;
+	case IIO_PROXIMITY:
+		/* Get proximity raw value */
+		ret = apds9930_read_word(client, APDS9930_PDATAL_REG, &ch);
+		if (ret < 0)
+			break;
+
+		*val	= APDS9930_MAX_PS_THRESH - (int)ch;
+		ret	= IIO_VAL_INT;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+/* Event handling functions */
+static int apds9930_read_event_config(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      enum iio_event_type type,
+				      enum iio_event_direction dir)
+{
+	struct apds9930_data *data = iio_priv(indio_dev);
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		return data->als_intr_state;
+	case IIO_PROXIMITY:
+		return data->ps_intr_state;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int apds9930_write_event_config(struct iio_dev *indio_dev,
+				       const struct iio_chan_spec *chan,
+				       enum iio_event_type type,
+				       enum iio_event_direction dir,
+				       int state)
+{
+	struct apds9930_data *data	= iio_priv(indio_dev);
+	struct i2c_client *client	= data->client;
+	u8 enable_reg, which_intr;
+	int ret;
+	bool *intr_state_addr;
+
+	if (chan->type != IIO_INTENSITY)
+		return -EINVAL;
+
+	mutex_lock(&data->mutex);
+
+	ret = apds9930_read_byte(client, APDS9930_ENABLE_REG, &enable_reg);
+	if (ret < 0)
+		goto err;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		which_intr	= APDS9930_AIEN;
+		intr_state_addr	= &data->als_intr_state;
+		break;
+	case IIO_PROXIMITY:
+		which_intr	= APDS9930_PIEN;
+		intr_state_addr	= &data->ps_intr_state;
+		break;
+	default:
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (state)
+		enable_reg |= which_intr;	/* enable */
+	else
+		enable_reg &= ~which_intr;	/* disable */
+
+	ret = apds9930_write_byte(client, APDS9930_ENABLE_REG, enable_reg);
+	if (ret == 0)
+		*intr_state_addr = (bool)state;
+err:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+
+static int apds9930_read_event_value(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir,
+				     enum iio_event_info info,
+				     int *val, int *val2)
+{
+	struct apds9930_data *data = iio_priv(indio_dev);
+	struct apds9930_threshold thresh;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		thresh = data->als_thresh;
+		break;
+	case IIO_PROXIMITY:
+		thresh = data->ps_thresh;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (dir) {
+	case IIO_EV_DIR_RISING:
+		*val = (int)(thresh.high);
+		break;
+	case IIO_EV_DIR_FALLING:
+		*val = (int)(thresh.low);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return IIO_VAL_INT;
+}
+
+/* IIO device specific data structures */
+static const struct iio_info apds9930_info = {
+	.driver_module		= THIS_MODULE,
+	.read_raw		= apds9930_read_raw,
+	.read_event_config	= apds9930_read_event_config,
+	.write_event_config	= apds9930_write_event_config,
+	.read_event_value	= apds9930_read_event_value,
+};
+
+/* Event specs for ALS and PS thresholds. Both of them behave in the same
+ * manner, thus define only one set of specifications.
+ */
+static const struct iio_event_spec apds9930_event_spec[] = {
+	{
+		/* "above threshold" event */
+		.type		= IIO_EV_TYPE_THRESH,
+		.dir		= IIO_EV_DIR_RISING,
+		.mask_separate	= BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE),
+	}, {
+		/* "below threshold" event */
+		.type		= IIO_EV_TYPE_THRESH,
+		.dir		= IIO_EV_DIR_FALLING,
+		.mask_separate	= BIT(IIO_EV_INFO_VALUE) |
+			BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+static const struct iio_chan_spec apds9930_channels[] = {
+	{
+		/* Lux (processed Ch0 + Ch1) */
+		.type			= IIO_LIGHT,
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_PROCESSED),
+	}, {
+		/* Ch0 photodiode (visible light + infrared); threshold
+		 * triggered event */
+		.type			= IIO_INTENSITY,
+		.channel		= 0,
+		.modified		= true,
+		.channel2		= IIO_MOD_LIGHT_BOTH,
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
+		.event_spec		= apds9930_event_spec,
+		.num_event_specs	= ARRAY_SIZE(apds9930_event_spec),
+	}, {
+		/* Ch1 photodiode (infrared) */
+		.type			= IIO_INTENSITY,
+		.channel		= 1,
+		.modified		= true,
+		.channel2		= IIO_MOD_LIGHT_IR,
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
+	}, {
+		/* Proximity channel; threshold triggered event */
+		.type			= IIO_PROXIMITY,
+		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
+		.event_spec		= apds9930_event_spec,
+		.num_event_specs	= ARRAY_SIZE(apds9930_event_spec),
+	}
+};
+
+/* Determine what has triggered the interrupt and clear it accordingly */
+static int apds9930_interrupt_clear(struct apds9930_data *data, u8 intr_status)
+{
+	u8 reg = 0x00;
+
+	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_SPECIAL_FUNC);
+
+	switch (intr_status & (APDS9930_AINT | APDS9930_PINT)) {
+	case APDS9930_AINT:
+		reg |= APDS9930_CMD_TYPE_ALS;
+		break;
+	case APDS9930_PINT:
+		reg |= APDS9930_CMD_TYPE_PS;
+		break;
+	case (APDS9930_AINT & APDS9930_PINT):
+		reg |= APDS9930_CMD_TYPE_BOTH;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return i2c_smbus_read_byte_data(data->client, reg);
+}
+
+/* ALS interrupt handler */
+static irqreturn_t apds9930_irq_handler(int irq, void *private_data)
+{
+	struct iio_dev *indio_dev	= private_data;
+	struct apds9930_data *data	= iio_priv(indio_dev);
+	u8 status, enable_reg;
+	u16 ch0, ps_data;
+	int ret;
+
+	/* Disable ADCs converters while processing data */
+	ret = apds9930_read_byte(data->client, APDS9930_ENABLE_REG,
+				 &enable_reg);
+	if (ret < 0)
+		return IRQ_HANDLED;
+	ret = apds9930_write_byte(data->client, APDS9930_ENABLE_REG, 1);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	/* Read status register to see what caused the interrupt */
+	ret = apds9930_read_byte(data->client, APDS9930_STATUS_REG, &status);
+	if (ret < 0)
+		goto err;
+
+	/* Push event to userspace */
+	if (status & APDS9930_AINT) {
+		/* Clear interrupt */
+		apds9930_interrupt_clear(data, status);
+
+		iio_push_event(indio_dev,
+			       IIO_MOD_EVENT_CODE(IIO_INTENSITY,
+						  0,
+						  IIO_MOD_LIGHT_BOTH,
+						  IIO_EV_TYPE_THRESH,
+						  IIO_EV_DIR_EITHER),
+			       iio_get_time_ns());
+
+		ret = apds9930_read_word(data->client, APDS9930_CDATAL_REG,
+					 &ch0);
+		if (ret < 0)
+			goto err;
+
+		apds9930_update_again(data, ch0);
+
+		/* Update ALS thresholds to environment */
+		apds9930_update_als_thresholds(data, ch0);
+	}
+
+	if (status & APDS9930_PINT) {
+		/* Clear interrupt */
+		apds9930_interrupt_clear(data, status);
+
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY,
+						    0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_EITHER),
+			       iio_get_time_ns());
+
+		ret = apds9930_read_word(data->client, APDS9930_PDATAL_REG,
+					 &ps_data);
+		if (ret < 0)
+			goto err;
+
+		apds9930_update_ps_thresholds(data, ps_data);
+	}
+
+err:
+	/* Re-enable converters */
+	apds9930_write_byte(data->client, APDS9930_ENABLE_REG, enable_reg);
+
+	return IRQ_HANDLED;
+}
+
+static int apds9930_gpio_probe(struct i2c_client *client,
+			       struct apds9930_data *data)
+{
+	struct device *dev;
+	struct gpio_desc *gpio;
+	int ret;
+
+	if (!client)
+		return -EINVAL;
+
+	dev = &client->dev;
+
+	gpio = devm_gpiod_get_index(dev, APDS9930_GPIO_NAME, 0);
+	if (IS_ERR(gpio)) {
+		dev_err(dev, "ACPI GPIO get index failed\n");
+		return PTR_ERR(gpio);
+	}
+
+	ret = gpiod_direction_input(gpio);
+	if (ret)
+		return ret;
+
+	return gpiod_to_irq(gpio);
+}
+
+static int apds9930_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct apds9930_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->mutex);
+
+	/* Recommended wait time after power on. */
+	msleep(APDS9930_INIT_SLEEP);
+
+	/* Check if the chip is the one we are expecting */
+	ret = apds9930_chip_detect(data);
+	if (ret < 0)
+		goto err;
+
+	apds9930_chip_data_init(data);
+
+	/* Disable and powerdown device */
+	ret = apds9930_disable_all(data);
+	if (ret < 0)
+		return ret;
+	ret = apds9930_chip_registers_init(data);
+	if (ret < 0)
+		return ret;
+	/* Power the device back on */
+	ret = apds9930_enable_all(data);
+	if (ret < 0)
+		return ret;
+
+	indio_dev->dev.parent	= &client->dev;
+	indio_dev->name		= APDS9930_DRIVER_NAME;
+	indio_dev->modes	= INDIO_DIRECT_MODE;
+	indio_dev->channels	= apds9930_channels;
+	indio_dev->num_channels	= ARRAY_SIZE(apds9930_channels);
+	indio_dev->info		= &apds9930_info;
+
+	if (client->irq <= 0)
+		client->irq = apds9930_gpio_probe(client, data);
+
+	if (client->irq > 0) {
+		ret = devm_request_threaded_irq(&client->dev,
+						client->irq,
+						NULL,
+						apds9930_irq_handler,
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+						APDS9930_IRQ_NAME,
+						indio_dev);
+		if (ret < 0)
+			goto err;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto err;
+
+	return 0;
+err:
+	apds9930_disable_all(data);
+
+	return ret;
+}
+
+static int apds9930_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev	= i2c_get_clientdata(client);
+	struct apds9930_data *data	= iio_priv(indio_dev);
+	int ret;
+
+	iio_device_unregister(indio_dev);
+	ret = apds9930_disable_all(data);
+
+	return ret;
+}
+
+static const struct acpi_device_id apds9930_acpi_table[] = {
+	{"APDS9930", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, apds9930_acpi_table);
+
+static const struct i2c_device_id apds9930_ids_table[] = {
+	{"apds9930", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, apds9930_ids_table);
+
+static struct i2c_driver apds9930_iio_driver = {
+	.driver	= {
+		.name			= APDS9930_DRIVER_NAME,
+		.acpi_match_table	= ACPI_PTR(apds9930_acpi_table),
+		.owner			= THIS_MODULE,
+	},
+	.probe		= apds9930_probe,
+	.remove		= apds9930_remove,
+	.id_table	= apds9930_ids_table,
+};
+module_i2c_driver(apds9930_iio_driver);
+
+MODULE_AUTHOR("Cristina Ciocan <cristina.ciocan@intel.com>");
+MODULE_DESCRIPTION("APDS9930 ALS and proximity sensor IIO driver");
+MODULE_LICENSE("GPL v2");
--
1.8.1.2

Re: [PATCH v2 1/1] iio:light: Avago APDS9930 ALS and proximity sensor

[Jonathan Cameron]

On 08/04/15 16:28, Cristina Ciocan wrote:
> Added IIO driver for Avago's APDS9930 ALS and proximity sensor.
> 
> It offers ACPI/DT support, irq and event handling, raw readings for both ALS and
> proximity.
> 
> Datasheet for this device can be found at:
> 	http://www.avagotech.com/docs/AV02-3190EN
> 
> Signed-off-by: Cristina Ciocan <cristina.ciocan@intel.com>
Various bits inline.  Also device tree properties that are undocumented.... You
need to add that and get a device tree ack (so cc the listed maintainers and list).

Getting there.  I'd still like you to have at least a quick go at merging this
with the adps9300 driver.  If it looks tricky then fair enough, but at least superficially
it doesn't look that bad.

Jonathan
> ---
>  drivers/iio/light/Kconfig    |   10 +
>  drivers/iio/light/Makefile   |    1 +
>  drivers/iio/light/apds9930.c | 1097 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1108 insertions(+)
>  create mode 100644 drivers/iio/light/apds9930.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 01a1a16..f5fa235 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -37,6 +37,16 @@ config APDS9300
>  	 To compile this driver as a module, choose M here: the
>  	 module will be called apds9300.
> 
> +config APDS9930
> +	tristate "APDS9930 ambient light and proximity sensor"
> +	depends on I2C
> +	help
> +	 Say Y here if you want to build a driver for the Avago APDS9930
> +	 ambient light and proximity sensor.
> +
> +	 To compile this driver as a module, choose M here: the
> +	 module will be called apds9930.
> +
>  config CM32181
>  	depends on I2C
>  	tristate "CM32181 driver"
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index ad7c30f..535d289 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
>  obj-$(CONFIG_AL3320A)		+= al3320a.o
>  obj-$(CONFIG_APDS9300)		+= apds9300.o
> +obj-$(CONFIG_APDS9930)		+= apds9930.o
>  obj-$(CONFIG_CM32181)		+= cm32181.o
>  obj-$(CONFIG_CM3232)		+= cm3232.o
>  obj-$(CONFIG_CM3323)		+= cm3323.o
> diff --git a/drivers/iio/light/apds9930.c b/drivers/iio/light/apds9930.c
> new file mode 100644
> index 0000000..fa5fb51
> --- /dev/null
> +++ b/drivers/iio/light/apds9930.c
> @@ -0,0 +1,1097 @@
> +/*
> + * This is a driver for Avago APDS9930 ALS and proxmity sensor chip. It
> + * is inspired from drivers/iio/misc/apds990x.c to use IIO.
> + *
> + * The I2C slave address for this device is 0x39.
> + *
> + * This program is distributed in the hope that 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.
> + *
> + * TODO: runtime pm support
> + */
> +
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/pm.h>
> +#include <linux/mutex.h>
> +#include <linux/kernel.h>
> +#include <linux/mutex.h>
> +#include <linux/interrupt.h>
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/property.h>
> +#include <linux/bitops.h>
> +
> +#include <linux/iio/types.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/events.h>
> +
> +#include <linux/gpio/consumer.h>
> +
> +#define APDS9930_DRIVER_NAME	"apds9930"
> +#define APDS9930_IRQ_NAME	"apds9930_irq"
> +#define APDS9930_GPIO_NAME	"apds9930_gpio"
> +
> +#define APDS9930_INIT_SLEEP	5 /* sleep for 5 ms before issuing commands */
> +
> +/* Register set (rw = read/write, r = read, w = write) */
> +#define APDS9930_ENABLE_REG	0x00	/* rw-Enable of states and interrupts */
> +#define APDS9930_ATIME_REG	0x01	/* rw-ALS ADC time*/
> +#define APDS9930_PTIME_REG	0x02	/* rw-Proximity ADC time */
> +#define APDS9930_WTIME_REG	0x03	/* rw-Wait time */
> +#define APDS9930_AILTL_REG	0x04	/* rw-ALS interrupt low threshold low
> +					 * byte
> +					 */
> +#define APDS9930_AIHTL_REG	0x06	/* rw-ALS interrupt high threshold low
> +					 * byte
> +					 */
> +#define APDS9930_PILTL_REG	0x08	/* rw-Proximity interrupt low threshold
> +					 * low byte
> +					 */
> +#define APDS9930_PIHTL_REG	0x0A	/* rw-Proximity interrupt high threshold
> +					 * low byte
> +					 */
> +#define APDS9930_PERS_REG	0x0C	/* rw-Interrupt persistence filters */
> +#define APDS9930_CONFIG_REG	0x0D	/* rw-Configuration */
> +#define APDS9930_PPULSE_REG	0x0E	/* rw-Proximity pulse control */
> +#define APDS9930_CONTROL_REG	0x0F	/* rw-Gain control register */
> +#define APDS9930_ID_REG		0x12	/* r-Device ID */
> +#define APDS9930_STATUS_REG	0x13	/* r-Device status */
> +#define APDS9930_CDATAL_REG	0x14	/* r-Ch0 ADC low data register */
> +#define APDS9930_CDATAH_REG	0x15	/* r-Ch0 ADC high data register */
> +#define APDS9930_IRDATAL_REG	0x16	/* r-Ch1 ADC low data register */
> +#define APDS9930_IRDATAH_REG	0x17	/* r-Ch1 ADC high data register */
> +#define APDS9930_PDATAL_REG	0x18	/* r-Proximity ADC low data register */
> +#define APDS9930_POFFSET_REG	0x1E	/* rw-Proximity offset register */
> +
> +/* Useful bits per register */
> +
> +/* Enable register */
> +#define APDS9930_SAI	BIT(6)	/* Sleep after interrupt */
> +#define APDS9930_PIEN	BIT(5)	/* Proximity interrupt enable */
> +#define APDS9930_AIEN	BIT(4)	/* ALS interrupt enable */
> +#define APDS9930_WEN	BIT(3)	/* Wait enable */
> +#define APDS9930_PEN	BIT(2)	/* Proximity enable */
> +#define APDS9930_AEN	BIT(1)	/* ALS enable */
> +#define APDS9930_PON	BIT(0)	/* Power ON */
> +
> +/* Persistence register */
> +#define APDS9930_PPERS_SHIFT	4	/* Proximity interrupt persistence */
> +#define APDS9930_APERS_SHIFT	0	/* Interrupt persistence */
> +
> +/* Configuration register */
> +#define APDS9930_AGL_SHIFT	2	/* ALS gain level */
> +#define APDS9930_WLONG_SHIFT	1	/* Wait long */
> +#define APDS9930_PDL_SHIFT	0	/* Proximity drive level */
> +
> +/* Control register */
> +#define APDS9930_PDRIVE_SHIFT	6	/* LED drive strength */
> +#define APDS9930_PDIODE_SHIFT	4	/* Proximity diode select */
> +#define APDS9930_PGAIN_SHIFT	2	/* Proximity gain control */
> +#define APDS9930_AGAIN_SHIFT	0	/* ALS gain control */
> +
> +/* Device ID - possible values */
> +#define APDS9930_ID	0x39
> +
> +/* Status register */
> +#define APDS9930_PSAT	BIT(6)	/* Proximity saturation */
> +#define APDS9930_PINT	BIT(5)	/* Proximity interrupt */
> +#define APDS9930_AINT	BIT(4)	/* ALS interrupt */
> +#define APDS9930_PVALID	BIT(1)	/* PS valid */
> +#define APDS9930_AVALID	BIT(0)	/* ALS valid */
> +
> +/* I2C command register - fields and possible field values */
> +#define APDS9930_CMD_TYPE_SHIFT		5
> +#define APDS9930_CMD_ADDR_SHIFT		0
> +/* CMD bit value must be set to 1 when addressing command register */
> +#define APDS9930_CMD_SELECT		0x80
> +/* TYPE possible values */
> +#define APDS9930_CMD_TYPE_RB		0		/* Repeated byte */
> +#define APDS9930_CMD_TYPE_AUTO_INC	BIT(5)		/* Auto-increment */
> +#define APDS9930_CMD_TYPE_SPECIAL_FUNC	GENMASK(6, 5)	/* Special function */
> +/* ADDR possible values */
> +#define APDS9930_CMD_TYPE_NONE		0x0	/* Normal - no action */
> +#define APDS9930_CMD_TYPE_PS		0x5	/* Proximity interrupt clear */
> +#define APDS9930_CMD_TYPE_ALS		0x6	/* ALS interrupt clear */
> +#define APDS9930_CMD_TYPE_BOTH		0x7	/* Both interrupt clear */
> +/* Clear masks */
> +#define APDS9930_CLEAR_CMD_TYPE_MASK	~(0x7 << APDS9930_CMD_TYPE_SHIFT)
> +/* Shortcut to clear and set CMD and TYPE fields */
> +#define APDS9930_CMD_REG_SETUP(reg, transaction_type) {		\
> +	reg &= APDS9930_CLEAR_CMD_TYPE_MASK;		\
> +	reg |= APDS9930_CMD_SELECT | transaction_type;	\
> +}
> +
> +/* Default values for registers content */
> +#define APDS9930_DISABLE_ALL	0	/* Disable and powerdown */
> +#define APDS9930_ENABLE_ALL	0x37	/* Set all ALS & PS bits and power on */
First two aren't default values (or at least they aren't both!)
> +#define APDS9930_DEF_ATIME	0xdb	/* 50 ms - ALSIT value in order to
> +					 * reject 50/60 Hz ripple; if higher
> +					 * resolution is needed, increase ALSIT
> +					 * with mutiples of 50
> +					 */
> +#define APDS9930_DEF_PTIME	0xff	/* 2.7 ms - min prox integration time */
> +#define APDS9930_DEF_WTIME	0xff	/* 2.7 ms - min wait time */
> +#define APDS9930_DEF_PPULSE	8	/* Min prox pulse count */
> +#define APDS9930_DEF_PDRIVE	0	/* 100 mA of LED power */
> +#define APDS9930_DEF_PDIODE	2	/* Ch1 diode (shifted value) */
> +#define APDS9930_DEF_PGAIN	2	/* 4 x proximity gain */
> +#define APDS9930_DEF_AGAIN	2	/* 16 x ALS gain */
> +#define APDS9930_DEF_WEN	8	/* Enable wait */
> +#define APDS9930_DEF_PEN	4	/* Enable proximity */
> +#define APDS9930_DEF_AEN	2	/* Enable ALS */
> +#define APDS9930_DEF_PON	1	/* Power ON */
> +#define APDS9930_DEF_APERS	3	/* Consecutive exceeding threshold
> +					 * cycles to trigger ALS interrupt
> +					 */
> +#define APDS9930_DEF_PPERS	3	/* Consecutive PS execeeding threshold
> +					 * cycles to trigger PS interrupt
> +					 */
> +
> +/* Interrupt threshold defaults - setting low to maximum will trigger a first
> + * interrupt to allow us to read the data registers status and properly set a
> + * threshold value to match the current environment.
> + *
> + * The default high threshold is set only for consistency, since the registers
> + * are checked against in order: first if the value of CDATA/PDATA is above LOW;
> + * if so, trigger interrupt and do not check the HIGH threshold.
> + */
> +#define APDS9930_DEF_ALS_THRESH_LOW	0xffff
> +#define APDS9930_DEF_ALS_THRESH_HIGH	0x0
> +#define APDS9930_DEF_PS_THRESH_LOW	1023
> +#define APDS9930_DEF_PS_THRESH_HIGH	0
> +
> +#define APDS9930_MIN_PS_THRESH		0	/* No object near the sensor */
> +#define APDS9930_MAX_PS_THRESH		1023	/* Object in close proximity */
> +#define APDS9930_DETECTION_PS_THRESH	600	/* Object detected near-by */
> +
> +/* Default, open air, coefficients (for Lux computation) */
> +#define APDS9930_DEF_DF	52	/* Device factor */
> +/* Material-depending coefficients (set to open air values). They are scaled for
> + * computation purposes by 100 (as stored in APDS9930_COEF_SCALE).
> + */
> +#define APDS9930_DEF_LUX_DIVISION_SCALE	10000
> +#define APDS9930_DEF_GA			49
> +#define APDS9930_DEF_B			186
> +#define APDS9930_DEF_C			74
> +#define APDS9930_DEF_D			129
> +#define APDS9930_COEF_SCALE		100
> +
> +/* Possible ALS gain values (with AGL cleared) */
> +static const int apds9930_again_values[] = {1, 8, 16, 120};
> +#define APDS9930_MAX_AGAIN_INDEX	3
> +#define APDS9930_AGL_DIVISION_SCALE	6
> +
> +/* Percentages from the maximum CH0 value that indicate the recorded CH0 data is
> + * too low or too high - for AGAIN adapting purposes.
> + */
> +#define APDS9930_CH0_HIGH_PERCENTAGE	90
> +#define APDS9930_CH0_LOW_PERCENTAGE	10
> +
> +/* With how much (in percentages) must the CH0 value differ from one step to
> + * another in order to consider a significant change in light.
> + */
> +#define APDS9930_ALS_HYSTERESIS		20
> +
> +/* DT or ACPI device properties names */
> +#define APDS9930_GA_PROP	"intel,ga"
> +#define APDS9930_COEF_B_PROP	"intel,coeff-B"
> +#define APDS9930_COEF_C_PROP	"intel,coeff-C"
> +#define APDS9930_COEF_D_PROP	"intel,coeff-D"
> +#define APDS9930_DF_PROP	"intel,df"
> +#define APDS9930_AGAIN_PROP	"intel,als-gain"
> +#define APDS9930_ATIME_PROP	"intel,atime"
> +#define APDS9930_PDRIVE_PROP	"intel,pdrive"
> +#define APDS9930_PPULSE_PROP	"intel,ppcount"
umm. Isn't this an avago part rather than an intel one?  Should be prefixed
with their string. Good of intel to write the driver an all, but remember
device tree data is reflecting the hardware not the driver...

> +
> +struct apds9930_coefficients {
> +	/* GA, B, C and D coefficients are scaled by 100 for computational
> +	 * purposes
> +	 */
> +	int ga;
> +	/* This is 1, but needs to be set to a scaled value, thus if
> +	 * we decide to change the scale, this coefficient must also
> +	 * be changed.
> +	 */
> +	int coef_a;
> +	int coef_b;
> +	int coef_c;
> +	int coef_d;
> +	int df;
> +};
> +
> +struct apds9930_platform_data {
> +	/* Glass-influenced factors */
> +	struct apds9930_coefficients coefs;
> +
> +	/* ALS platform data */
> +	u8 again;	/* AGAIN value (index in apds9930_again_values[]) */
> +	u8 atime;	/* ALS integration time */
> +
> +	/* Proximity platform data */
> +	u8 pdrive;
> +	u8 ppulse;
> +};
> +
> +struct apds9930_threshold {
> +	u16 low;
> +	u16 high;
> +};
> +
> +struct apds9930_data {
> +	struct i2c_client	*client;
> +
> +	/* Protect access to device data */
> +	struct mutex		mutex;
> +
> +	/* Platform specific data */
> +	struct apds9930_platform_data	platform_data;
> +
> +#define __coefs		platform_data.coefs
> +#define __again		platform_data.again
> +#define __atime		platform_data.atime
> +#define __pdrive	platform_data.pdrive
> +#define __ppulse	platform_data.ppulse
Don't do this.  It might feel like a good idea, but it just
makes the code harder to read.
> +
> +	u8	alsit;
> +	u16	ch0_max;		/* Maximum possible Ch0 data value */
> +	bool	agl_enabled;
> +
> +	bool	als_intr_state;
> +	bool	ps_intr_state;
> +	struct apds9930_threshold	als_thresh;
> +	struct apds9930_threshold	ps_thresh;
> +};
> +
> +/* Writes data to the register; the next i2c_write call will write to the same
> + * register
> + */
> +static inline int apds9930_write_byte(struct i2c_client *client, u8 reg,
> +				      u8 data)
> +{
> +	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_RB);
I'm not convinced this utility macro really adds anything.  Slightly shorter
code, but less obvious what it is doing...
> +
> +	return i2c_smbus_write_byte_data(client, reg, data);
> +}
> +
> +/* Reads data from a register; the next i2c_read call will read from the same
> + * address
> + */
> +static inline int apds9930_read_byte(struct i2c_client *client, u8 reg,
> +				     u8 *data)
> +{
> +	int ret;
> +
> +	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_RB);
> +	ret	= i2c_smbus_read_byte_data(client, reg);
> +	*data	= ret;
> +
> +	return ret;
> +}
> +
> +/* Writes 2 bytes at the given address */
> +static inline int apds9930_write_word(struct i2c_client *client, u8 reg,
> +				      u16 data)
> +{
> +	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_AUTO_INC);
> +
> +	return i2c_smbus_write_word_data(client, reg, data);
> +}
> +
> +/* Reads 2 bytes from the given address */
> +static inline int apds9930_read_word(struct i2c_client *client, u8 reg,
> +				     u16 *data)
> +{
> +	int ret;
> +
> +	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_AUTO_INC);
> +	ret	= i2c_smbus_read_word_data(client, reg);
> +	*data	= ret;
> +
> +	return ret;
> +}
> +
> +/* ALSIT = 2.73ms * (256 - ATIME), 2.73 = 5591/(2^11) */
> +static inline u8 apds9930_atime_to_alsit(u8 atime_val)
> +{
> +	return (u8)(((256 - (u32)atime_val) * 5591) >> 11);
> +}
> +
> +/* ATIME = 256 - ALSIT/2.73ms, 1/2.73 = 375/(2^10) */
> +static inline u8 apds9930_alsit_to_atime(u8 alsit_val)
> +{
> +	return (u8)(256 - (((u32)alsit_val * 375) >> 10));
> +}
> +
> +/* Computes maximum Ch0 data when atime is the given one. */
> +static inline u16 apds9930_compute_max_ch0(u8 atime_val)
> +{
> +	return 1024 * (256 - (u32)atime_val) - 1;
> +}
> +
> +/* Computes the ALS gain value for the next step and updates the current one */
> +static void apds9930_update_again(struct apds9930_data *data, u16 ch0)
Hmm. again is a bit of a missleading name.
I briefly wondered why you needed to do it more than once before realising
it was analog or als gain...  Perhaps expand that name a little!
> +{
> +	int current_index, next_index, err;
> +
> +	/* Compute the value for the next measurement */
> +	current_index	= data->__again;
> +	next_index	= data->__again;
> +
> +	/* CH0 data too high, try to lower the ALS gain if possible */
> +	if (ch0 >= (data->ch0_max * APDS9930_CH0_HIGH_PERCENTAGE) / 100) {
> +		if (next_index == 0 && !(data->agl_enabled)) {
> +			err = apds9930_write_byte(
> +						  data->client,
> +						  APDS9930_CONFIG_REG,
> +						  1 << APDS9930_AGL_SHIFT);
> +			if (!err)
> +				data->agl_enabled = true;
> +		} else if (next_index > 0) {
> +			next_index--;
> +		}
> +	}
> +
> +	/* CH0 data too low, try to increase the ALS gain if possible */
> +	else if (ch0 <= (data->ch0_max * APDS9930_CH0_LOW_PERCENTAGE) / 100) {
> +		if (data->agl_enabled) {
> +			err = apds9930_write_byte(data->client,
> +						  APDS9930_CONFIG_REG,
> +						  0);
> +			if (!err)
> +				data->agl_enabled = false;
> +		} else if (next_index < APDS9930_MAX_AGAIN_INDEX) {
> +			next_index++;
> +		}
> +	}
> +
> +	if (next_index != current_index) {
> +		/* Update data's index value */
> +		data->__again = next_index;
> +
> +		/* Update AGAIN for the next reading */
> +		apds9930_write_byte(
> +				data->client,
> +				APDS9930_CONTROL_REG,
> +				data->__again << APDS9930_AGAIN_SHIFT |
> +				APDS9930_DEF_PGAIN << APDS9930_PGAIN_SHIFT |
> +				APDS9930_DEF_PDIODE << APDS9930_PDIODE_SHIFT |
> +				data->__pdrive << APDS9930_PDRIVE_SHIFT);
> +	}
> +}
> +
> +/* Update thresholds so as to generate interrupts when the CH0 data changes
> + * significantly since the last update; significantly is quantified by the
> + * hysteresis factor: if the ALS state changes with more than hysteresis %,
> + * update the thresholds.
Comment syntax wrong.  Please check for other instances of this...
/*
 * Update
> + */
> +static void apds9930_update_als_thresholds(struct apds9930_data *data, u16 ch0)
> +{
> +	data->als_thresh.low	= (ch0 * (100 - APDS9930_ALS_HYSTERESIS)) / 100;
> +	data->als_thresh.high	= min((ch0 *
> +				       (100 + APDS9930_ALS_HYSTERESIS)) / 100,
> +				      data->ch0_max);
> +
> +	apds9930_write_word(data->client, APDS9930_AILTL_REG,
> +			    data->als_thresh.low);
> +	apds9930_write_word(data->client, APDS9930_AIHTL_REG,
> +			    data->als_thresh.high);
> +}
> +
> +static void apds9930_update_ps_thresholds(struct apds9930_data *data, u16 ps)
> +{
> +	if (ps <= data->ps_thresh.low) {
> +		/* Near to far => set limits to detect when it comes close */
> +		data->ps_thresh.low	= APDS9930_MIN_PS_THRESH;
> +		data->ps_thresh.high	= APDS9930_DETECTION_PS_THRESH;
> +	} else if (ps >= data->ps_thresh.high) {
> +		/* Far to near => set limits to detect when it goes further */
> +		data->ps_thresh.low	= APDS9930_DETECTION_PS_THRESH;
> +		data->ps_thresh.high	= APDS9930_MAX_PS_THRESH;
> +	}
> +
> +	/* Update thresholds */
> +	apds9930_write_word(data->client, APDS9930_PILTL_REG,
> +			    data->ps_thresh.low);
> +	apds9930_write_word(data->client, APDS9930_PIHTL_REG,
> +			    data->ps_thresh.high);
> +}
> +
> +/* Having the channel 0 and channels 1's data, compute the Lux value */
> +static int apds9930_compute_lux(struct apds9930_data *data, u16 ch0, u16 ch1)
> +{
> +	long int iac1, iac2, alsit_val, again_val, tmp_iac;
> +	unsigned long int iac, lux;
> +	struct apds9930_coefficients cf;
> +
> +	/* Lux equation */
> +	cf		= data->__coefs;
> +	iac1		= cf.coef_a * ch0 - cf.coef_b * ch1;
> +	iac2		= cf.coef_c * ch0 - cf.coef_d * ch1;
> +	tmp_iac         = max(iac1, iac2);
> +	iac             = (tmp_iac < 0) ? 0 : (unsigned long)tmp_iac;
> +	alsit_val	= (int)(data->alsit);
> +	again_val	= apds9930_again_values[data->__again];
> +	lux		= (iac * cf.ga * cf.df) /
> +				(alsit_val * again_val *
> +				 APDS9930_DEF_LUX_DIVISION_SCALE);
> +
> +	return data->agl_enabled ? (APDS9930_AGL_DIVISION_SCALE * lux) : lux;
> +}
> +
> +static int apds9930_enable_all(struct apds9930_data *data)
> +{
> +	int ret;
> +
> +	mutex_lock(&data->mutex);
> +	ret = apds9930_write_byte(data->client, APDS9930_ENABLE_REG,
> +				  APDS9930_ENABLE_ALL);
> +	if (ret < 0)
> +		goto err;
> +
> +	data->als_intr_state	= true;
> +	data->ps_intr_state	= true;
> +err:
> +	mutex_unlock(&data->mutex);
> +
> +	return ret;
> +}
> +
> +static int apds9930_disable_all(struct apds9930_data *data)
> +{
> +	int ret;
> +
> +	mutex_lock(&data->mutex);
> +	ret = apds9930_write_byte(data->client, APDS9930_ENABLE_REG,
> +				  APDS9930_DISABLE_ALL);
> +	if (ret < 0)
> +		goto err;
> +
> +	data->als_intr_state	= false;
> +	data->ps_intr_state	= false;
> +err:
> +	mutex_unlock(&data->mutex);
> +
> +	return ret;
> +}
> +
> +static int apds9930_chip_detect(struct apds9930_data *data)
> +{
> +	int ret;
> +	u8 id;
> +
> +	ret = apds9930_read_byte(data->client, APDS9930_ID_REG, &id);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (id != APDS9930_ID)
> +		ret = -EINVAL;
> +
> +	return ret;
> +}
> +
> +/* Set the coefficients to those specified in properties if they exist,
> + * otherwise to default values.
> + */
> +static void apds9930_set_platform_data(struct apds9930_data *data)
> +{
> +	struct apds9930_platform_data *pdata = data->client->dev.platform_data;
> +	struct apds9930_coefficients defaults = {
> +		.ga	= APDS9930_DEF_GA,
> +		.coef_a	= APDS9930_COEF_SCALE,
> +		.coef_b	= APDS9930_DEF_B,
> +		.coef_c	= APDS9930_DEF_C,
> +		.coef_d	= APDS9930_DEF_D,
> +		.df	= APDS9930_DEF_DF,
> +	};
> +	struct device *dev = &data->client->dev;
> +
> +	/* Look for platform data */
> +	if (pdata) {
> +		data->__again	= pdata->again;
> +		data->__atime	= pdata->atime;
> +		data->__pdrive	= pdata->pdrive;
> +		data->__ppulse	= pdata->ppulse;
> +
> +		if (pdata->coefs.ga == 0)
> +			data->__coefs = defaults;
> +		else
> +			data->__coefs = pdata->coefs;
> +
> +		return;
> +	}
> +
> +	/* Look for device properties and set them to proper value or to
> +	 * default. */
> +	if (device_property_read_u32(dev, APDS9930_GA_PROP, &data->__coefs.ga))
> +		data->__coefs.ga = defaults.ga;
> +
> +	if (device_property_read_u32(dev, APDS9930_DF_PROP, &data->__coefs.df))
> +		data->__coefs.df = defaults.df;
> +
> +	if (device_property_read_u32(dev, APDS9930_COEF_B_PROP,
> +				     &data->__coefs.coef_b) ||
> +	    device_property_read_u32(dev, APDS9930_COEF_C_PROP,
> +				     &data->__coefs.coef_c) ||
> +	    device_property_read_u32(dev, APDS9930_COEF_D_PROP,
> +				     &data->__coefs.coef_d)) {
> +		data->__coefs.coef_b	= defaults.coef_b;
> +		data->__coefs.coef_c	= defaults.coef_c;
> +		data->__coefs.coef_d	= defaults.coef_d;
> +	}
> +	data->__coefs.coef_a = defaults.coef_a;
> +
> +	if (device_property_read_u8(dev, APDS9930_ATIME_PROP, &data->__atime))
> +		data->__atime = APDS9930_DEF_ATIME;
> +
> +	if (device_property_read_u8(dev, APDS9930_AGAIN_PROP, &data->__again))
> +		data->__again = APDS9930_DEF_AGAIN;
> +
> +	/* We expect for the AGAIN value to be the one in the register (0, 1, 2
> +	 * or 3). If we do find device property AGAIN, but is not valid, fall
> +	 * back to the default one.
> +	 */
> +	if (data->__again > APDS9930_MAX_AGAIN_INDEX)
> +		data->__again = APDS9930_DEF_AGAIN;
> +
> +	if (device_property_read_u8(dev, APDS9930_PDRIVE_PROP, &data->__pdrive))
> +		data->__pdrive = APDS9930_DEF_PDRIVE;
> +
> +	if (device_property_read_u8(dev, APDS9930_PPULSE_PROP, &data->__ppulse))
> +		data->__ppulse = APDS9930_DEF_PPULSE;
> +}
> +
> +static void apds9930_chip_data_init(struct apds9930_data *data)
> +{
> +	apds9930_set_platform_data(data);
> +
> +	/* Init data to default values */
> +	data->alsit		= apds9930_atime_to_alsit(data->__atime);
> +	data->ch0_max		= apds9930_compute_max_ch0(APDS9930_DEF_ATIME);
> +	data->agl_enabled	= false;
> +	data->als_intr_state	= false;
> +	data->ps_intr_state	= false;
> +	data->als_thresh.low	= APDS9930_DEF_ALS_THRESH_LOW;
> +	data->als_thresh.high	= APDS9930_DEF_ALS_THRESH_HIGH;
> +	data->ps_thresh.low	= APDS9930_DEF_PS_THRESH_LOW;
> +	data->ps_thresh.high	= APDS9930_DEF_PS_THRESH_HIGH;
> +}
> +
> +/* Basic chip initialization, as described in the datasheet */
> +static int apds9930_chip_registers_init(struct apds9930_data *data)
> +{
> +	struct i2c_client *client = data->client;
> +	int ret;
> +
> +	/* Set timing registers default values (minimum) */
> +	ret = apds9930_write_byte(client, APDS9930_ATIME_REG, (data->__atime));
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = apds9930_write_byte(client, APDS9930_PTIME_REG,
> +				  APDS9930_DEF_PTIME);
> +	if (ret < 0)
> +		return ret;
> +	ret = apds9930_write_byte(client, APDS9930_WTIME_REG,
> +				  APDS9930_DEF_WTIME);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Interrupt threshold default settings */
> +	ret = apds9930_write_word(client, APDS9930_AILTL_REG,
> +				  APDS9930_DEF_ALS_THRESH_LOW);
> +	if (ret < 0)
> +		return ret;
> +	ret = apds9930_write_word(client, APDS9930_AIHTL_REG,
> +				  APDS9930_DEF_ALS_THRESH_HIGH);
> +	if (ret < 0)
> +		return ret;
> +	ret = apds9930_write_word(client, APDS9930_PILTL_REG,
> +				  APDS9930_DEF_PS_THRESH_LOW);
> +	if (ret < 0)
> +		return ret;
> +	ret = apds9930_write_word(client, APDS9930_PIHTL_REG,
> +				  APDS9930_DEF_PS_THRESH_HIGH);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Set persistence filters to default values */
> +	ret = apds9930_write_byte(client, APDS9930_PERS_REG,
> +				  APDS9930_DEF_APERS << APDS9930_APERS_SHIFT |
> +				  APDS9930_DEF_PPERS << APDS9930_PPERS_SHIFT);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Reset the configuration register (do not wait long) */
> +	ret = apds9930_write_byte(client, APDS9930_CONFIG_REG, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Set proximity pulse count register (number of pulses to be generated
> +	 * during the proximity accum state)
Comment format wrong for a multiline comment.
> +	 */
> +	ret = apds9930_write_byte(client, APDS9930_PPULSE_REG, data->__ppulse);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Gain selection setting */
> +	return apds9930_write_byte(
> +				client, APDS9930_CONTROL_REG,
> +				data->__again << APDS9930_AGAIN_SHIFT |
> +				APDS9930_DEF_PGAIN << APDS9930_PGAIN_SHIFT |
> +				APDS9930_DEF_PDIODE << APDS9930_PDIODE_SHIFT |
> +				data->__pdrive << APDS9930_PDRIVE_SHIFT);
> +}
> +
> +static int apds9930_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan, int *val,
> +			     int *val2, long mask)
> +{
> +	struct apds9930_data *data	= iio_priv(indio_dev);
> +	struct i2c_client *client	= data->client;
> +	int ret;
> +	u16 ch0, ch1, ch;
> +
> +	mutex_lock(&data->mutex);
> +	switch (chan->type) {
> +	case IIO_LIGHT:
> +		/* Get Lux value */
> +		ret = apds9930_read_word(client, APDS9930_CDATAL_REG, &ch0);
> +		if (ret < 0)
> +			break;
> +		ret = apds9930_read_word(client, APDS9930_IRDATAL_REG, &ch1);
> +		if (ret < 0)
> +			break;
> +
> +		/* Compute Lux value and check its validity */
validity check?
> +		*val = apds9930_compute_lux(data, ch0, ch1);
> +		apds9930_update_again(data, ch0);
> +		ret = IIO_VAL_INT;
> +		break;
> +	case IIO_INTENSITY:
> +		/* Get ch0 or ch1 raw value */
> +		ret = apds9930_read_word(client, chan->channel ?
> +					 APDS9930_IRDATAL_REG :
> +					 APDS9930_CDATAL_REG,
> +					 &ch);
> +		if (ret < 0)
> +			break;
> +
> +		*val	= (int)ch;
> +		ret	= IIO_VAL_INT;
> +		break;
> +	case IIO_PROXIMITY:
> +		/* Get proximity raw value */
> +		ret = apds9930_read_word(client, APDS9930_PDATAL_REG, &ch);
> +		if (ret < 0)
> +			break;
> +
> +		*val	= APDS9930_MAX_PS_THRESH - (int)ch;
> +		ret	= IIO_VAL_INT;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +	mutex_unlock(&data->mutex);
> +
> +	return ret;
> +}
> +
> +/* Event handling functions */
> +static int apds9930_read_event_config(struct iio_dev *indio_dev,
> +				      const struct iio_chan_spec *chan,
> +				      enum iio_event_type type,
> +				      enum iio_event_direction dir)
> +{
> +	struct apds9930_data *data = iio_priv(indio_dev);
> +
> +	switch (chan->type) {
> +	case IIO_INTENSITY:
> +		return data->als_intr_state;
> +	case IIO_PROXIMITY:
> +		return data->ps_intr_state;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int apds9930_write_event_config(struct iio_dev *indio_dev,
> +				       const struct iio_chan_spec *chan,
> +				       enum iio_event_type type,
> +				       enum iio_event_direction dir,
> +				       int state)
> +{
> +	struct apds9930_data *data	= iio_priv(indio_dev);
> +	struct i2c_client *client	= data->client;
> +	u8 enable_reg, which_intr;
> +	int ret;
> +	bool *intr_state_addr;
> +
> +	if (chan->type != IIO_INTENSITY)
> +		return -EINVAL;
> +
> +	mutex_lock(&data->mutex);
> +
> +	ret = apds9930_read_byte(client, APDS9930_ENABLE_REG, &enable_reg);
> +	if (ret < 0)
> +		goto err;
> +
> +	switch (chan->type) {
> +	case IIO_INTENSITY:
> +		which_intr	= APDS9930_AIEN;
> +		intr_state_addr	= &data->als_intr_state;
> +		break;
> +	case IIO_PROXIMITY:
> +		which_intr	= APDS9930_PIEN;
> +		intr_state_addr	= &data->ps_intr_state;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	if (state)
> +		enable_reg |= which_intr;	/* enable */
> +	else
> +		enable_reg &= ~which_intr;	/* disable */
> +
> +	ret = apds9930_write_byte(client, APDS9930_ENABLE_REG, enable_reg);
> +	if (ret == 0)
> +		*intr_state_addr = (bool)state;
> +err:
> +	mutex_unlock(&data->mutex);
> +
> +	return ret;
> +}
> +
> +static int apds9930_read_event_value(struct iio_dev *indio_dev,
> +				     const struct iio_chan_spec *chan,
> +				     enum iio_event_type type,
> +				     enum iio_event_direction dir,
> +				     enum iio_event_info info,
> +				     int *val, int *val2)
> +{
> +	struct apds9930_data *data = iio_priv(indio_dev);
> +	struct apds9930_threshold thresh;
> +
> +	switch (chan->type) {
> +	case IIO_INTENSITY:
> +		thresh = data->als_thresh;
> +		break;
> +	case IIO_PROXIMITY:
> +		thresh = data->ps_thresh;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	switch (dir) {
> +	case IIO_EV_DIR_RISING:
> +		*val = (int)(thresh.high);
> +		break;
> +	case IIO_EV_DIR_FALLING:
> +		*val = (int)(thresh.low);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return IIO_VAL_INT;
> +}
> +
> +/* IIO device specific data structures */
> +static const struct iio_info apds9930_info = {
> +	.driver_module		= THIS_MODULE,
> +	.read_raw		= apds9930_read_raw,
> +	.read_event_config	= apds9930_read_event_config,
> +	.write_event_config	= apds9930_write_event_config,
> +	.read_event_value	= apds9930_read_event_value,
> +};
> +
> +/* Event specs for ALS and PS thresholds. Both of them behave in the same
> + * manner, thus define only one set of specifications.
> + */
> +static const struct iio_event_spec apds9930_event_spec[] = {
> +	{
> +		/* "above threshold" event */
> +		.type		= IIO_EV_TYPE_THRESH,
> +		.dir		= IIO_EV_DIR_RISING,
> +		.mask_separate	= BIT(IIO_EV_INFO_VALUE) |
> +			BIT(IIO_EV_INFO_ENABLE),
> +	}, {
> +		/* "below threshold" event */
> +		.type		= IIO_EV_TYPE_THRESH,
> +		.dir		= IIO_EV_DIR_FALLING,
> +		.mask_separate	= BIT(IIO_EV_INFO_VALUE) |
> +			BIT(IIO_EV_INFO_ENABLE),
> +	},
> +};
> +
> +static const struct iio_chan_spec apds9930_channels[] = {
> +	{
> +		/* Lux (processed Ch0 + Ch1) */
> +		.type			= IIO_LIGHT,
> +		.info_mask_separate	= BIT(IIO_CHAN_INFO_PROCESSED),
> +	}, {
> +		/* Ch0 photodiode (visible light + infrared); threshold
> +		 * triggered event */
> +		.type			= IIO_INTENSITY,
> +		.channel		= 0,
> +		.modified		= true,
> +		.channel2		= IIO_MOD_LIGHT_BOTH,
> +		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
> +		.event_spec		= apds9930_event_spec,
> +		.num_event_specs	= ARRAY_SIZE(apds9930_event_spec),
> +	}, {
> +		/* Ch1 photodiode (infrared) */
> +		.type			= IIO_INTENSITY,
> +		.channel		= 1,
> +		.modified		= true,
> +		.channel2		= IIO_MOD_LIGHT_IR,
> +		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
> +	}, {
> +		/* Proximity channel; threshold triggered event */
> +		.type			= IIO_PROXIMITY,
> +		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW),
> +		.event_spec		= apds9930_event_spec,
> +		.num_event_specs	= ARRAY_SIZE(apds9930_event_spec),
> +	}
> +};
> +
> +/* Determine what has triggered the interrupt and clear it accordingly */
> +static int apds9930_interrupt_clear(struct apds9930_data *data, u8 intr_status)
> +{
> +	u8 reg = 0x00;
> +
> +	APDS9930_CMD_REG_SETUP(reg, APDS9930_CMD_TYPE_SPECIAL_FUNC);
> +
> +	switch (intr_status & (APDS9930_AINT | APDS9930_PINT)) {
> +	case APDS9930_AINT:
> +		reg |= APDS9930_CMD_TYPE_ALS;
> +		break;
> +	case APDS9930_PINT:
> +		reg |= APDS9930_CMD_TYPE_PS;
> +		break;
> +	case (APDS9930_AINT & APDS9930_PINT):
Drop unnecessary bracket.
> +		reg |= APDS9930_CMD_TYPE_BOTH;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return i2c_smbus_read_byte_data(data->client, reg);
> +}
> +
> +/* ALS interrupt handler */
> +static irqreturn_t apds9930_irq_handler(int irq, void *private_data)
> +{
> +	struct iio_dev *indio_dev	= private_data;
> +	struct apds9930_data *data	= iio_priv(indio_dev);
> +	u8 status, enable_reg;
> +	u16 ch0, ps_data;
> +	int ret;
> +
> +	/* Disable ADCs converters while processing data */
> +	ret = apds9930_read_byte(data->client, APDS9930_ENABLE_REG,
> +				 &enable_reg);
> +	if (ret < 0)
> +		return IRQ_HANDLED;
> +	ret = apds9930_write_byte(data->client, APDS9930_ENABLE_REG, 1);
> +	if (ret < 0)
> +		return IRQ_HANDLED;
> +
> +	/* Read status register to see what caused the interrupt */
> +	ret = apds9930_read_byte(data->client, APDS9930_STATUS_REG, &status);
> +	if (ret < 0)
> +		goto err;
> +
> +	/* Push event to userspace */
> +	if (status & APDS9930_AINT) {
> +		/* Clear interrupt */
> +		apds9930_interrupt_clear(data, status);
> +
> +		iio_push_event(indio_dev,
> +			       IIO_MOD_EVENT_CODE(IIO_INTENSITY,
> +						  0,
> +						  IIO_MOD_LIGHT_BOTH,
> +						  IIO_EV_TYPE_THRESH,
> +						  IIO_EV_DIR_EITHER),
> +			       iio_get_time_ns());
> +
> +		ret = apds9930_read_word(data->client, APDS9930_CDATAL_REG,
> +					 &ch0);
> +		if (ret < 0)
> +			goto err;
> +
> +		apds9930_update_again(data, ch0);
> +
> +		/* Update ALS thresholds to environment */
> +		apds9930_update_als_thresholds(data, ch0);
> +	}
> +
> +	if (status & APDS9930_PINT) {
> +		/* Clear interrupt */
> +		apds9930_interrupt_clear(data, status);
> +
> +		iio_push_event(indio_dev,
> +			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY,
> +						    0,
> +						    IIO_EV_TYPE_THRESH,
> +						    IIO_EV_DIR_EITHER),
> +			       iio_get_time_ns());
> +
> +		ret = apds9930_read_word(data->client, APDS9930_PDATAL_REG,
> +					 &ps_data);
> +		if (ret < 0)
> +			goto err;
> +
> +		apds9930_update_ps_thresholds(data, ps_data);
> +	}
> +
> +err:
> +	/* Re-enable converters */
> +	apds9930_write_byte(data->client, APDS9930_ENABLE_REG, enable_reg);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int apds9930_gpio_probe(struct i2c_client *client,
> +			       struct apds9930_data *data)
> +{
Hopefully the various discussions on some core support for
this will bare fruit and avoid yet another copy of this boiler plate.
In the meantime I guess we have to leave it here though...
> +	struct device *dev;
> +	struct gpio_desc *gpio;
> +	int ret;
> +
> +	if (!client)
> +		return -EINVAL;
> +
> +	dev = &client->dev;
> +
> +	gpio = devm_gpiod_get_index(dev, APDS9930_GPIO_NAME, 0);
> +	if (IS_ERR(gpio)) {
> +		dev_err(dev, "ACPI GPIO get index failed\n");
> +		return PTR_ERR(gpio);
> +	}
> +
> +	ret = gpiod_direction_input(gpio);
> +	if (ret)
> +		return ret;
> +
> +	return gpiod_to_irq(gpio);
> +}
> +
> +static int apds9930_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	struct apds9930_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->mutex);
> +
> +	/* Recommended wait time after power on. */
> +	msleep(APDS9930_INIT_SLEEP);

> +
> +	/* Check if the chip is the one we are expecting */
> +	ret = apds9930_chip_detect(data);
> +	if (ret < 0)
Would be more obviously correct to just duplicate the error
handling here.  Otherwise requires a bit of thought when reviewing
and I never like that ;)
> +		goto err;
> +
> +	apds9930_chip_data_init(data);
> +
> +	/* Disable and powerdown device */
> +	ret = apds9930_disable_all(data);
> +	if (ret < 0)
> +		return ret;
> +	ret = apds9930_chip_registers_init(data);
> +	if (ret < 0)
> +		return ret;
> +	/* Power the device back on */
> +	ret = apds9930_enable_all(data);
> +	if (ret < 0)
> +		return ret;
> +
> +	indio_dev->dev.parent	= &client->dev;
> +	indio_dev->name		= APDS9930_DRIVER_NAME;
> +	indio_dev->modes	= INDIO_DIRECT_MODE;
> +	indio_dev->channels	= apds9930_channels;
> +	indio_dev->num_channels	= ARRAY_SIZE(apds9930_channels);
> +	indio_dev->info		= &apds9930_info;
> +
> +	if (client->irq <= 0)
> +		client->irq = apds9930_gpio_probe(client, data);
> +
> +	if (client->irq > 0) {
> +		ret = devm_request_threaded_irq(&client->dev,
> +						client->irq,
> +						NULL,
> +						apds9930_irq_handler,
> +						IRQF_TRIGGER_FALLING |
> +						IRQF_ONESHOT,
> +						APDS9930_IRQ_NAME,
> +						indio_dev);
> +		if (ret < 0)
> +			goto err;
> +	}
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0)
> +		goto err;
> +
> +	return 0;
> +err:
> +	apds9930_disable_all(data);
> +
> +	return ret;
> +}
> +
> +static int apds9930_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev	= i2c_get_clientdata(client);
> +	struct apds9930_data *data	= iio_priv(indio_dev);
> +	int ret;
> +
> +	iio_device_unregister(indio_dev);
> +	ret = apds9930_disable_all(data);
> +
> +	return ret;
return apds9930_disable_all(data); and drop the int ret as well.
> +}
> +
> +static const struct acpi_device_id apds9930_acpi_table[] = {
> +	{"APDS9930", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(acpi, apds9930_acpi_table);
> +
> +static const struct i2c_device_id apds9930_ids_table[] = {
> +	{"apds9930", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, apds9930_ids_table);
> +
> +static struct i2c_driver apds9930_iio_driver = {
> +	.driver	= {
> +		.name			= APDS9930_DRIVER_NAME,
> +		.acpi_match_table	= ACPI_PTR(apds9930_acpi_table),
> +		.owner			= THIS_MODULE,
> +	},
> +	.probe		= apds9930_probe,
> +	.remove		= apds9930_remove,
> +	.id_table	= apds9930_ids_table,
> +};
> +module_i2c_driver(apds9930_iio_driver);
> +
> +MODULE_AUTHOR("Cristina Ciocan <cristina.ciocan@intel.com>");
> +MODULE_DESCRIPTION("APDS9930 ALS and proximity sensor IIO driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.8.1.2
>