[PATCH 1/2] iio: light: add driver for veml6030 ambient light sensor

From: Rishi Gupta
Date: Tue Sep 17 2019 - 23:09:47 EST

veml6030 is an ambient light sensor from Vishay semiconductors.
It has 16-bit resolution, supports both ambient light measurement
and white channel which is more responsive to wider wavelength
spectrum. It has flexible power saving, integration time and
gain options. Communication with host is over I2C.

Signed-off-by: Rishi Gupta <gupt21@xxxxxxxxx>
---
drivers/iio/light/Kconfig | 11 +
drivers/iio/light/Makefile | 1 +
drivers/iio/light/veml6030.c | 647 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 659 insertions(+)
create mode 100644 drivers/iio/light/veml6030.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index e3fd00b..9afe997 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -484,6 +484,17 @@ config VCNL4035
To compile this driver as a module, choose M here: the
module will be called vcnl4035.

+config VEML6030
+ tristate "VEML6030 ambient light sensor"
+ select REGMAP_I2C
+ depends on I2C
+ help
+ Say Y here if you want to build a driver for the Vishay VEML6030
+ ambient light sensor (ALS).
+
+ To compile this driver as a module, choose M here: the
+ module will be called veml6030.
+
config VEML6070
tristate "VEML6070 UV A light sensor"
depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index e40794f..011968b 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_TSL4531) += tsl4531.o
obj-$(CONFIG_US5182D) += us5182d.o
obj-$(CONFIG_VCNL4000) += vcnl4000.o
obj-$(CONFIG_VCNL4035) += vcnl4035.o
+obj-$(CONFIG_VEML6030) += veml6030.o
obj-$(CONFIG_VEML6070) += veml6070.o
obj-$(CONFIG_VL6180) += vl6180.o
obj-$(CONFIG_ZOPT2201) += zopt2201.o
diff --git a/drivers/iio/light/veml6030.c b/drivers/iio/light/veml6030.c
new file mode 100644
index 0000000..b12cdce
--- /dev/null
+++ b/drivers/iio/light/veml6030.c
@@ -0,0 +1,647 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * VEML6030 Ambient Light Sensor
+ *
+ * Copyright (c) 2019, Rishi Gupta <gupt21@xxxxxxxxx>
+ *
+ * Datasheet: https://www.vishay.com/docs/84366/veml6030.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/regmap.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/pm_runtime.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+/* Device registers */
+#define VEML6030_REG_ALS_CONF 0x00
+#define VEML6030_REG_ALS_WH 0x01
+#define VEML6030_REG_ALS_WL 0x02
+#define VEML6030_REG_ALS_PSM 0x03
+#define VEML6030_REG_ALS_DATA 0x04
+#define VEML6030_REG_WHITE_DATA 0x05
+#define VEML6030_REG_ALS_INT 0x06
+
+/* Bit masks for specific functionality */
+#define VEML6030_ALS_IT GENMASK(9, 6)
+#define VEML6030_PSM GENMASK(2, 1)
+#define VEML6030_ALS_PERS GENMASK(5, 4)
+#define VEML6030_ALS_GAIN GENMASK(12, 11)
+#define VEML6030_PSM_EN BIT(0)
+#define VEML6030_INT_TH_LOW BIT(15)
+#define VEML6030_INT_TH_HIGH BIT(14)
+#define VEML6030_ALS_INT_EN BIT(1)
+#define VEML6030_ALS_SD BIT(0)
+
+struct veml6030_data {
+ struct i2c_client *client;
+ struct regmap *regmap;
+};
+
+static IIO_CONST_ATTR_INT_TIME_AVAIL("0.025 0.05 0.1 0.2 0.4 0.8");
+
+static struct attribute *veml6030_attributes[] = {
+ &iio_const_attr_integration_time_available.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group veml6030_attr_group = {
+ .attrs = veml6030_attributes,
+};
+
+/*
+ * Scale is 1/gain. Value 0.125 is ALS gain x (1/8), 0.25 is
+ * ALS gain x (1/4), 1.0 = ALS gain x 1 and 2.0 is ALS gain x 2.
+ */
+static ssize_t veml6030_scale_available(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+ return sprintf(buf, "%s\n", "0.125 0.25 1.0 2.0");
+}
+
+/*
+ * Persistence = 1/2/4/8 x integration time
+ * Minimum time for which light readings must stay above configured
+ * threshold to assert interrupt.
+ */
+static ssize_t veml6030_persistence_available(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+ return sprintf(buf, "%s\n", "1 2 4 8");
+}
+
+/*
+ * Power saving modes supported.
+ * 1/2/3/4 corresponds to PSM modes 1/2/3/4 respectively.
+ */
+static ssize_t veml6030_psm_available(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+ return sprintf(buf, "%s\n", "1 2 3 4");
+}
+
+ssize_t veml6030_set_psm(struct iio_dev *indio_dev, uintptr_t priv,
+ const struct iio_chan_spec *chan, const char *buf,
+ size_t len)
+{
+ int ret;
+ unsigned int val;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ ret = kstrtouint(buf, 0, &val);
+ if (ret < 0)
+ return ret;
+
+ if (val < 1 || val > 4)
+ return -EINVAL;
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_PSM,
+ VEML6030_PSM | VEML6030_PSM_EN, val - 1);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "can't update psm value %d\n", ret);
+ return ret;
+ }
+
+ return len;
+}
+
+#define VEML6030_AVAIL(_name, _read) \
+{ \
+ .name = (_name "_available"), \
+ .read = _read, \
+ .shared = IIO_SEPARATE, \
+}
+
+static const struct iio_chan_spec_ext_info veml6030_ext_info[] = {
+ {
+ .name = "psm",
+ .write = veml6030_set_psm,
+ .shared = IIO_SEPARATE,
+ },
+ VEML6030_AVAIL("psm", veml6030_psm_available),
+ VEML6030_AVAIL("scale", veml6030_scale_available),
+ VEML6030_AVAIL("period", veml6030_persistence_available),
+ { },
+};
+
+static const struct iio_event_spec veml6030_event_spec[] = {
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_RISING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE),
+ }, {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_FALLING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE),
+ }, {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_EITHER,
+ .mask_separate = BIT(IIO_EV_INFO_PERIOD),
+ }, {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_EITHER,
+ .mask_separate = BIT(IIO_EV_INFO_ENABLE),
+ },
+};
+
+/*
+ * This is used to specify both scan index and numerical
+ * channel number in channel specifications.
+ */
+enum veml6030_chan {
+ CH_ALS,
+ CH_WHITE
+};
+
+static const struct iio_chan_spec veml6030_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .channel = CH_ALS,
+ .scan_index = CH_ALS,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_LE,
+ },
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_INT_TIME) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .event_spec = veml6030_event_spec,
+ .num_event_specs = ARRAY_SIZE(veml6030_event_spec),
+ .ext_info = veml6030_ext_info,
+ },
+ {
+ .type = IIO_INTENSITY,
+ .channel = CH_WHITE,
+ .modified = 1,
+ .channel2 = IIO_MOD_LIGHT_BOTH,
+ .scan_index = CH_WHITE,
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_LE,
+ },
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW)
+ },
+};
+
+static const struct regmap_config veml6030_regmap_config = {
+ .name = "veml6030_regmap",
+ .reg_bits = 8,
+ .val_bits = 16,
+ .max_register = VEML6030_REG_ALS_INT,
+ .val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int veml6030_set_als_gain(struct iio_dev *indio_dev,
+ int val, int val2)
+{
+ int ret, gain;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ if (val == 0 && val2 == 125000)
+ gain = 0x02;
+ else if (val == 0 && val2 == 250000)
+ gain = 0x03;
+ else if (val == 1 && val2 == 0)
+ gain = 0x00;
+ else if (val == 2 && val2 == 0)
+ gain = 0x01;
+ else
+ return -EINVAL;
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_GAIN, gain);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "can't set ALS gain %d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+static int veml6030_set_als_persistence(struct iio_dev *indio_dev,
+ int val, int val2)
+{
+ int ret;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ if (val < 0 || val > 8 || hweight8(val) != 1 || val2)
+ return -EINVAL;
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_PERS, val);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "can't set persistence value %d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+static int veml6030_set_als_threshold(struct iio_dev *indio_dev,
+ int val, int val2, int dir)
+{
+ int ret;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ if (val > 0xFFFF || val < 0 || val2)
+ return -EINVAL;
+
+ if (dir == IIO_EV_DIR_RISING) {
+ ret = regmap_write(data->regmap, VEML6030_REG_ALS_WH, val);
+ if (ret)
+ dev_err(&data->client->dev,
+ "can't set high threshold %d\n", ret);
+ } else {
+ ret = regmap_write(data->regmap, VEML6030_REG_ALS_WL, val);
+ if (ret)
+ dev_err(&data->client->dev,
+ "can't set low threshold %d\n", ret);
+ }
+
+ return ret;
+}
+
+static int veml6030_set_integration_time(struct iio_dev *indio_dev,
+ int val, int val2)
+{
+ int ret, int_time;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ if (val)
+ return -EINVAL;
+
+ switch (val2) {
+ case 25000:
+ int_time = 12;
+ break;
+ case 50000:
+ int_time = 8;
+ break;
+ case 100000:
+ int_time = 0;
+ break;
+ case 200000:
+ int_time = 1;
+ break;
+ case 400000:
+ int_time = 2;
+ break;
+ case 800000:
+ int_time = 3;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_IT, int_time);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "can't update integration time %d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+/*
+ * Light reading in lux is obtained by multiplying a constant
+ * specified in appnote 84367 in the lux calculation table
+ * to the raw reading.
+ */
+static int veml6030_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ int ret, rdval;
+ struct veml6030_data *data = iio_priv(indio_dev);
+ struct regmap *regmap = data->regmap;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ ret = regmap_read(regmap, VEML6030_REG_ALS_DATA, &rdval);
+ if (ret < 0) {
+ dev_err(&data->client->dev, "can't read ALS data\n");
+ return ret;
+ }
+ *val = rdval;
+ return IIO_VAL_INT;
+ case IIO_INTENSITY:
+ ret = regmap_read(regmap, VEML6030_REG_WHITE_DATA, &rdval);
+ if (ret < 0) {
+ dev_err(&data->client->dev, "can't read white data\n");
+ return ret;
+ }
+ *val = rdval;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static int veml6030_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_INT_TIME:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ return veml6030_set_integration_time(indio_dev, val, val2);
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ return veml6030_set_als_gain(indio_dev, val, val2);
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static int veml6030_write_thresh(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)
+{
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ return veml6030_set_als_threshold(indio_dev, val, val2, dir);
+ case IIO_EV_INFO_PERIOD:
+ return veml6030_set_als_persistence(indio_dev, val, val2);
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static int veml6030_write_interrupt_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, enum iio_event_type type,
+ enum iio_event_direction dir, int state)
+{
+ int ret;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ if (!data->client->irq || state < 0 || state > 1)
+ return -EINVAL;
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_INT_EN, state);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "can't enable threshold interrupt %d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+static const struct iio_info veml6030_info = {
+ .read_raw = veml6030_read_raw,
+ .write_raw = veml6030_write_raw,
+ .write_event_value = veml6030_write_thresh,
+ .write_event_config = veml6030_write_interrupt_config,
+ .attrs = &veml6030_attr_group,
+};
+
+static irqreturn_t veml6030_event_handler(int irq, void *private)
+{
+ int ret, reg, evtdir;
+ struct iio_dev *indio_dev = private;
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ ret = regmap_read(data->regmap, VEML6030_REG_ALS_INT, &reg);
+ if (ret) {
+ dev_err(&data->client->dev,
+ "can't enable interrupt status %d\n", ret);
+ return IRQ_HANDLED;
+ }
+
+ /* Spurious interrupt handling */
+ if (!(reg & (VEML6030_INT_TH_HIGH | VEML6030_INT_TH_LOW)))
+ return IRQ_HANDLED;
+
+ if (reg & VEML6030_INT_TH_HIGH)
+ evtdir = IIO_EV_DIR_RISING;
+ else
+ evtdir = IIO_EV_DIR_FALLING;
+
+ iio_push_event(indio_dev, IIO_UNMOD_EVENT_CODE(IIO_INTENSITY,
+ 0, IIO_EV_TYPE_THRESH, evtdir),
+ iio_get_time_ns(indio_dev));
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Corresponding to 1200 ms as refresh time, set ALS gain to
+ * ALS gain x 2, integration time to 200 ms and PSM to mode 2.
+ * Set persistence to 1 x integration time, and the threashold
+ * interrupt disabled by default.
+ */
+static int veml6030_hw_init(struct iio_dev *indio_dev)
+{
+ int ret, val;
+ struct veml6030_data *data = iio_priv(indio_dev);
+ struct i2c_client *client = data->client;
+
+ ret = regmap_write(data->regmap, VEML6030_REG_ALS_CONF, 0x850);
+ if (ret) {
+ dev_err(&client->dev, "can't setup ALS configs %d\n", ret);
+ return ret;
+ }
+
+ /* Wait 4 ms to let processor & oscillator start correctly */
+ usleep_range(3990, 4000);
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_PSM,
+ VEML6030_PSM | VEML6030_PSM_EN, 0x03);
+ if (ret) {
+ dev_err(&client->dev, "can't setup defaults for PSM %d\n", ret);
+ return ret;
+ }
+
+ ret = regmap_write(data->regmap, VEML6030_REG_ALS_WH, 0xFFFF);
+ if (ret) {
+ dev_err(&client->dev, "can't read high threshold %d\n", ret);
+ return ret;
+ }
+
+ ret = regmap_write(data->regmap, VEML6030_REG_ALS_WL, 0x0000);
+ if (ret) {
+ dev_err(&client->dev, "can't read low threshold %d\n", ret);
+ return ret;
+ }
+
+ /* Clear stale interrupt status bits if any during start */
+ ret = regmap_read(data->regmap, VEML6030_REG_ALS_INT, &val);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "can't read ALS interrupt status %d\n", ret);
+ return ret;
+ }
+
+ return ret;
+}
+
+static int veml6030_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct veml6030_data *data;
+ struct iio_dev *indio_dev;
+ struct regmap *regmap;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_err(&client->dev, "i2c adapter doesn't support plain i2c\n");
+ return -EOPNOTSUPP;
+ }
+
+ regmap = devm_regmap_init_i2c(client, &veml6030_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(&client->dev, "can't setup regmap\n");
+ return PTR_ERR(regmap);
+ }
+
+ 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;
+ data->regmap = regmap;
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &veml6030_info;
+ indio_dev->name = "veml6030";
+ indio_dev->channels = veml6030_channels;
+ indio_dev->num_channels = ARRAY_SIZE(veml6030_channels);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ if (client->irq) {
+ ret = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, veml6030_event_handler,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ "veml6030", indio_dev);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "irq %d request failed\n", client->irq);
+ return ret;
+ }
+ }
+
+ ret = veml6030_hw_init(indio_dev);
+ if (ret < 0)
+ return ret;
+
+ return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static int veml6030_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_SD, 0x01);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int veml6030_runtime_suspend(struct device *dev)
+{
+ int ret;
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_SD, 0x01);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "can't suspend veml6030 light sensor\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+static int veml6030_runtime_resume(struct device *dev)
+{
+ int ret;
+ struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+ struct veml6030_data *data = iio_priv(indio_dev);
+
+ ret = regmap_update_bits(data->regmap, VEML6030_REG_ALS_CONF,
+ VEML6030_ALS_SD, 0x00);
+ if (ret < 0) {
+ dev_err(&data->client->dev,
+ "can't resume veml6030 light sensor\n");
+ return ret;
+ }
+
+ return ret;
+}
+
+static const struct dev_pm_ops veml6030_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+ pm_runtime_force_resume)
+ SET_RUNTIME_PM_OPS(veml6030_runtime_suspend,
+ veml6030_runtime_resume, NULL)
+};
+#endif
+
+static const struct of_device_id veml6030_of_match[] = {
+ { .compatible = "vishay,veml6030" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, veml6030_of_match);
+
+static const struct i2c_device_id veml6030_id[] = {
+ { "veml6030", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, veml6030_id);
+
+static struct i2c_driver veml6030_driver = {
+ .driver = {
+ .name = "veml6030",
+ .of_match_table = of_match_ptr(veml6030_of_match),
+#ifdef CONFIG_PM
+ .pm = &veml6030_pm_ops,
+#endif
+ },
+ .probe = veml6030_probe,
+ .remove = veml6030_remove,
+ .id_table = veml6030_id,
+};
+module_i2c_driver(veml6030_driver);
+
+MODULE_AUTHOR("Rishi Gupta <gupt21@xxxxxxxxx>");
+MODULE_DESCRIPTION("VEML6030 Ambient Light Sensor");
+MODULE_LICENSE("GPL v2");
--
2.7.4