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Subject[PATCH v4 2/2] iio: light: noa1305: Add support for NOA1305
Date
This driver adds the initial support for the ON Semiconductor
NOA1305 Ambient Light Sensor.

Originally written by Sergei Miroshnichenko. Found here:
https://github.com/EmcraftSystems/linux-upstream/commit/196d6cf897e632d2cb82d45484bd7a1bfdd5b6d9

Signed-off-by: Sergei M <fizik1@yandex.com>
Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
---

Changes:
v2:
- Correcting authorship and SOB.
v3:
- Improve register define naming.
- Follow IIO convention of interleaving register bit definitions with
register defintions.
- Use proper endian swapping.
- Process raw sensor count into Lux.
- Avoid setting variables to zero when not needed.
- Check return value of i2c writes.
- Implement disabling of regulator as a devm action.
- Remove excessive white spacing.
v4:
- Clean up returns
- Remove redundant noa1305_remove()
- Remove redundant interrupt configuration/disabling
- Return raw value and scaling

Note: Scaling added for all possible interation times to ensure the
mechanism utilised would allow this, though chip currently
statically configured to 800mS.

drivers/iio/light/Kconfig | 10 ++
drivers/iio/light/Makefile | 1 +
drivers/iio/light/noa1305.c | 312 ++++++++++++++++++++++++++++++++++++
3 files changed, 323 insertions(+)
create mode 100644 drivers/iio/light/noa1305.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 954c958cfc43..d1db0ec0d0f5 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -309,6 +309,16 @@ config MAX44009
To compile this driver as a module, choose M here:
the module will be called max44009.

+config NOA1305
+ tristate "ON Semiconductor NOA1305 ambient light sensor"
+ depends on I2C
+ help
+ Say Y here if you want to build support for the ON Semiconductor
+ NOA1305 ambient light sensor.
+
+ To compile this driver as a module, choose M here:
+ The module will be called noa1305.
+
config OPT3001
tristate "Texas Instruments OPT3001 Light Sensor"
depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index e40794fbb435..00d1f9b98f39 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_LTR501) += ltr501.o
obj-$(CONFIG_LV0104CS) += lv0104cs.o
obj-$(CONFIG_MAX44000) += max44000.o
obj-$(CONFIG_MAX44009) += max44009.o
+obj-$(CONFIG_NOA1305) += noa1305.o
obj-$(CONFIG_OPT3001) += opt3001.o
obj-$(CONFIG_PA12203001) += pa12203001.o
obj-$(CONFIG_RPR0521) += rpr0521.o
diff --git a/drivers/iio/light/noa1305.c b/drivers/iio/light/noa1305.c
new file mode 100644
index 000000000000..b8758aa7b32a
--- /dev/null
+++ b/drivers/iio/light/noa1305.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Support for ON Semiconductor NOA1305 ambient light sensor
+ *
+ * Copyright (C) 2016 Emcraft Systems
+ * Copyright (C) 2019 Collabora Ltd.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define NOA1305_REG_POWER_CONTROL 0x0
+#define NOA1305_POWER_CONTROL_DOWN 0x00
+#define NOA1305_POWER_CONTROL_ON 0x08
+#define NOA1305_REG_RESET 0x1
+#define NOA1305_RESET_RESET 0x10
+#define NOA1305_REG_INTEGRATION_TIME 0x2
+#define NOA1305_INTEGR_TIME_800MS 0x00
+#define NOA1305_INTEGR_TIME_400MS 0x01
+#define NOA1305_INTEGR_TIME_200MS 0x02
+#define NOA1305_INTEGR_TIME_100MS 0x03
+#define NOA1305_INTEGR_TIME_50MS 0x04
+#define NOA1305_INTEGR_TIME_25MS 0x05
+#define NOA1305_INTEGR_TIME_12_5MS 0x06
+#define NOA1305_INTEGR_TIME_6_25MS 0x07
+#define NOA1305_REG_INT_SELECT 0x3
+#define NOA1305_INT_SEL_ACTIVE_HIGH 0x01
+#define NOA1305_INT_SEL_ACTIVE_LOW 0x02
+#define NOA1305_INT_SEL_INACTIVE 0x03
+#define NOA1305_REG_INT_THRESH_LSB 0x4
+#define NOA1305_REG_INT_THRESH_MSB 0x5
+#define NOA1305_REG_ALS_DATA_LSB 0x6
+#define NOA1305_REG_ALS_DATA_MSB 0x7
+#define NOA1305_REG_DEVICE_ID_LSB 0x8
+#define NOA1305_REG_DEVICE_ID_MSB 0x9
+
+#define NOA1305_DEVICE_ID 0x0519
+#define NOA1305_DRIVER_NAME "noa1305"
+
+struct noa1305_priv {
+ struct i2c_client *client;
+ struct regmap *regmap;
+ struct regulator *vin_reg;
+};
+
+static int noa1305_measure(struct noa1305_priv *priv)
+{
+ __le16 data;
+ int ret;
+
+ ret = regmap_bulk_read(priv->regmap, NOA1305_REG_ALS_DATA_LSB, &data,
+ 2);
+ if (ret < 0)
+ return ret;
+
+ return le16_to_cpu(data);
+}
+
+static int noa1305_scale(struct noa1305_priv *priv, int *val, int *val2)
+{
+ int data;
+ int ret;
+
+ ret = regmap_read(priv->regmap, NOA1305_REG_INTEGRATION_TIME, &data);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * Lux = count / (<Integration Constant> * <Integration Time>)
+ *
+ * Integration Constant = 7.7
+ * Integration Time in Seconds
+ */
+ switch (data) {
+ case NOA1305_INTEGR_TIME_800MS:
+ *val = 100;
+ *val2 = 77 * 8;
+ break;
+ case NOA1305_INTEGR_TIME_400MS:
+ *val = 100;
+ *val2 = 77 * 4;
+ case NOA1305_INTEGR_TIME_200MS:
+ *val = 100;
+ *val2 = 77 * 2;
+ break;
+ case NOA1305_INTEGR_TIME_100MS:
+ *val = 100;
+ *val2 = 77;
+ break;
+ case NOA1305_INTEGR_TIME_50MS:
+ *val = 1000;
+ *val2 = 77 * 5;
+ break;
+ case NOA1305_INTEGR_TIME_25MS:
+ *val = 10000;
+ *val2 = 77 * 25;
+ break;
+ case NOA1305_INTEGR_TIME_12_5MS:
+ *val = 100000;
+ *val2 = 77 * 125;
+ break;
+ case NOA1305_INTEGR_TIME_6_25MS:
+ *val = 1000000;
+ *val2 = 77 * 625;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return IIO_VAL_FRACTIONAL;
+}
+
+static const struct iio_chan_spec noa1305_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ }
+};
+
+static int noa1305_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int ret = -EINVAL;
+ struct noa1305_priv *priv = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ ret = noa1305_measure(priv);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+ default:
+ break;
+ }
+ break;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ return noa1305_scale(priv, val, val2);
+ default:
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static const struct iio_info noa1305_info = {
+ .read_raw = noa1305_read_raw,
+};
+
+static bool noa1305_writable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case NOA1305_REG_POWER_CONTROL:
+ case NOA1305_REG_RESET:
+ case NOA1305_REG_INTEGRATION_TIME:
+ case NOA1305_REG_INT_SELECT:
+ case NOA1305_REG_INT_THRESH_LSB:
+ case NOA1305_REG_INT_THRESH_MSB:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static const struct regmap_config noa1305_regmap_config = {
+ .name = NOA1305_DRIVER_NAME,
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = NOA1305_REG_DEVICE_ID_MSB,
+ .writeable_reg = noa1305_writable_reg,
+};
+
+static void noa1305_reg_remove(void *data)
+{
+ struct noa1305_priv *priv = data;
+
+ regulator_disable(priv->vin_reg);
+}
+
+static int noa1305_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct noa1305_priv *priv;
+ struct iio_dev *indio_dev;
+ struct regmap *regmap;
+ __le16 data;
+ unsigned int dev_id;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*priv));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ regmap = devm_regmap_init_i2c(client, &noa1305_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(&client->dev, "Regmap initialization failed.\n");
+ return PTR_ERR(regmap);
+ }
+
+ priv = iio_priv(indio_dev);
+
+ priv->vin_reg = devm_regulator_get(&client->dev, "vin");
+ if (IS_ERR(priv->vin_reg)) {
+ dev_err(&client->dev, "get regulator vin failed\n");
+ return PTR_ERR(priv->vin_reg);
+ }
+
+ ret = regulator_enable(priv->vin_reg);
+ if (ret) {
+ dev_err(&client->dev, "enable regulator vin failed\n");
+ return ret;
+ }
+
+ ret = devm_add_action_or_reset(&client->dev, noa1305_reg_remove, priv);
+ if (ret) {
+ dev_err(&client->dev, "addition of devm action failed\n");
+ return ret;
+ }
+
+ i2c_set_clientdata(client, indio_dev);
+ priv->client = client;
+ priv->regmap = regmap;
+
+ ret = regmap_bulk_read(regmap, NOA1305_REG_DEVICE_ID_LSB, &data, 2);
+ if (ret < 0) {
+ dev_err(&client->dev, "ID reading failed: %d\n", ret);
+ return ret;
+ }
+
+ dev_id = le16_to_cpu(data);
+ if (dev_id != NOA1305_DEVICE_ID) {
+ dev_err(&client->dev, "Unknown device ID: 0x%x\n", dev_id);
+ return -ENODEV;
+ }
+
+ ret = regmap_write(regmap, NOA1305_REG_POWER_CONTROL,
+ NOA1305_POWER_CONTROL_ON);
+ if (ret < 0) {
+ dev_err(&client->dev, "Enabling power control failed\n");
+ return ret;
+ }
+
+ ret = regmap_write(regmap, NOA1305_REG_RESET, NOA1305_RESET_RESET);
+ if (ret < 0) {
+ dev_err(&client->dev, "Device reset failed\n");
+ return ret;
+ }
+
+ ret = regmap_write(regmap, NOA1305_REG_INTEGRATION_TIME,
+ NOA1305_INTEGR_TIME_800MS);
+ if (ret < 0) {
+ dev_err(&client->dev, "Setting integration time failed\n");
+ return ret;
+ }
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &noa1305_info;
+ indio_dev->channels = noa1305_channels;
+ indio_dev->num_channels = ARRAY_SIZE(noa1305_channels);
+ indio_dev->name = NOA1305_DRIVER_NAME;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = devm_iio_device_register(&client->dev, indio_dev);
+ if (ret)
+ dev_err(&client->dev, "registering device failed\n");
+
+ return ret;
+}
+
+static const struct of_device_id noa1305_of_match[] = {
+ { .compatible = "onnn,noa1305" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, noa1305_of_match);
+
+static const struct i2c_device_id noa1305_ids[] = {
+ { "noa1305", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, noa1305_id);
+
+static struct i2c_driver noa1305_driver = {
+ .driver = {
+ .name = NOA1305_DRIVER_NAME,
+ .of_match_table = noa1305_of_match,
+ },
+ .probe = noa1305_probe,
+ .id_table = noa1305_ids,
+};
+
+module_i2c_driver(noa1305_driver);
+
+MODULE_AUTHOR("Sergei Miroshnichenko <sergeimir@emcraft.com>");
+MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.com");
+MODULE_DESCRIPTION("ON Semiconductor NOA1305 ambient light sensor");
+MODULE_LICENSE("GPL");
--
2.20.1
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