[PATCH v2 1/5] max44000: Initial support

From: Crestez Dan Leonard
Date: Mon Apr 11 2016 - 14:52:59 EST

This just adds support for reporting illuminance with default settings.

Important default registers are written on probe because the device
otherwise lacks a reset function.

Signed-off-by: Crestez Dan Leonard <leonard.crestez@xxxxxxxxx>
---
drivers/iio/light/Kconfig | 11 ++
drivers/iio/light/Makefile | 1 +
drivers/iio/light/max44000.c | 336 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 348 insertions(+)
create mode 100644 drivers/iio/light/max44000.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index cfd3df8..b4ab65b 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -223,6 +223,17 @@ config LTR501
This driver can also be built as a module. If so, the module
will be called ltr501.

+config MAX44000
+ tristate "MAX44000 Ambient and Infrared Proximity Sensor"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ Say Y here if you want to build support for Maxim Integrated's
+ MAX44000 ambient and infrared proximity sensor device.
+
+ To compile this driver as a module, choose M here:
+ the module will be called max44000.
+
config OPT3001
tristate "Texas Instruments OPT3001 Light Sensor"
depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index b2c3105..c77f27f 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_ISL29125) += isl29125.o
obj-$(CONFIG_JSA1212) += jsa1212.o
obj-$(CONFIG_SENSORS_LM3533) += lm3533-als.o
obj-$(CONFIG_LTR501) += ltr501.o
+obj-$(CONFIG_MAX44000) += max44000.o
obj-$(CONFIG_OPT3001) += opt3001.o
obj-$(CONFIG_PA12203001) += pa12203001.o
obj-$(CONFIG_RPR0521) += rpr0521.o
diff --git a/drivers/iio/light/max44000.c b/drivers/iio/light/max44000.c
new file mode 100644
index 0000000..707cc24
--- /dev/null
+++ b/drivers/iio/light/max44000.c
@@ -0,0 +1,336 @@
+/*
+ * MAX44000 Ambient and Infrared Proximity Sensor
+ *
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Data sheet: https://datasheets.maximintegrated.com/en/ds/MAX44000.pdf
+ *
+ * 7-bit I2C slave address 0x4a
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/util_macros.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/acpi.h>
+
+#define MAX44000_DRV_NAME "max44000"
+
+/* Registers in datasheet order */
+#define MAX44000_REG_STATUS 0x00
+#define MAX44000_REG_CFG_MAIN 0x01
+#define MAX44000_REG_CFG_RX 0x02
+#define MAX44000_REG_CFG_TX 0x03
+#define MAX44000_REG_ALS_DATA_HI 0x04
+#define MAX44000_REG_ALS_DATA_LO 0x05
+#define MAX44000_REG_PRX_DATA 0x16
+#define MAX44000_REG_ALS_UPTHR_HI 0x06
+#define MAX44000_REG_ALS_UPTHR_LO 0x07
+#define MAX44000_REG_ALS_LOTHR_HI 0x08
+#define MAX44000_REG_ALS_LOTHR_LO 0x09
+#define MAX44000_REG_PST 0x0a
+#define MAX44000_REG_PRX_IND 0x0b
+#define MAX44000_REG_PRX_THR 0x0c
+#define MAX44000_REG_TRIM_GAIN_GREEN 0x0f
+#define MAX44000_REG_TRIM_GAIN_IR 0x10
+
+/* REG_CFG bits */
+#define MAX44000_CFG_ALSINTE 0x01
+#define MAX44000_CFG_PRXINTE 0x02
+#define MAX44000_CFG_MASK 0x1c
+#define MAX44000_CFG_MODE_SHUTDOWN 0x00
+#define MAX44000_CFG_MODE_ALS_GIR 0x04
+#define MAX44000_CFG_MODE_ALS_G 0x08
+#define MAX44000_CFG_MODE_ALS_IR 0x0c
+#define MAX44000_CFG_MODE_ALS_PRX 0x10
+#define MAX44000_CFG_MODE_PRX 0x14
+#define MAX44000_CFG_TRIM 0x20
+
+/*
+ * Upper 4 bits are not documented but start as 1 on powerup
+ * Setting them to 0 causes proximity to misbehave so set them to 1
+ */
+#define MAX44000_REG_CFG_RX_DEFAULT 0xf0
+
+#define MAX44000_ALSDATA_OVERFLOW 0x4000
+
+#define MAX44000_REGMASK_READABLE ( \
+ (1 << MAX44000_REG_STATUS) | \
+ (1 << MAX44000_REG_CFG_MAIN) | \
+ (1 << MAX44000_REG_CFG_RX) | \
+ (1 << MAX44000_REG_CFG_TX) | \
+ (1 << MAX44000_REG_ALS_DATA_HI) | \
+ (1 << MAX44000_REG_ALS_DATA_LO) | \
+ (1 << MAX44000_REG_PRX_DATA) | \
+ (1 << MAX44000_REG_ALS_UPTHR_HI) | \
+ (1 << MAX44000_REG_ALS_UPTHR_LO) | \
+ (1 << MAX44000_REG_ALS_LOTHR_HI) | \
+ (1 << MAX44000_REG_ALS_LOTHR_LO) | \
+ (1 << MAX44000_REG_PST) | \
+ (1 << MAX44000_REG_PRX_IND) | \
+ (1 << MAX44000_REG_PRX_THR) | \
+ (1 << MAX44000_REG_TRIM_GAIN_GREEN) | \
+ (1 << MAX44000_REG_TRIM_GAIN_IR))
+
+#define MAX44000_REGMASK_WRITEABLE ( \
+ (1 << MAX44000_REG_CFG_MAIN) | \
+ (1 << MAX44000_REG_CFG_RX) | \
+ (1 << MAX44000_REG_CFG_TX) | \
+ (1 << MAX44000_REG_ALS_UPTHR_HI) | \
+ (1 << MAX44000_REG_ALS_UPTHR_LO) | \
+ (1 << MAX44000_REG_ALS_LOTHR_HI) | \
+ (1 << MAX44000_REG_ALS_LOTHR_LO) | \
+ (1 << MAX44000_REG_PST) | \
+ (1 << MAX44000_REG_PRX_IND) | \
+ (1 << MAX44000_REG_PRX_THR) | \
+ (1 << MAX44000_REG_TRIM_GAIN_GREEN) | \
+ (1 << MAX44000_REG_TRIM_GAIN_IR))
+
+#define MAX44000_REGMASK_VOLATILE ( \
+ (1 << MAX44000_REG_STATUS) | \
+ (1 << MAX44000_REG_ALS_DATA_HI) | \
+ (1 << MAX44000_REG_ALS_DATA_LO) | \
+ (1 << MAX44000_REG_PRX_DATA))
+
+struct max44000_data {
+ struct mutex lock;
+ struct regmap *regmap;
+};
+
+/* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */
+#define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5
+
+static const struct iio_chan_spec max44000_channels[] = {
+ {
+ .type = IIO_LIGHT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static int max44000_read_alsval(struct max44000_data *data)
+{
+ u16 regval;
+ int ret;
+
+ ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI,
+ &regval, sizeof(regval));
+ if (ret < 0)
+ return ret;
+
+ regval = be16_to_cpu(regval);
+
+ /*
+ * Overflow is explained on datasheet page 17.
+ *
+ * It's a warning that either the G or IR channel has become saturated
+ * and that the value in the register is likely incorrect.
+ *
+ * The recommendation is to change the scale (ALSPGA).
+ * The driver just returns the max representable value.
+ */
+ if (regval & MAX44000_ALSDATA_OVERFLOW)
+ return 0x3FFF;
+
+ return regval;
+}
+
+static int max44000_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct max44000_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ mutex_lock(&data->lock);
+ ret = max44000_read_alsval(data);
+ mutex_unlock(&data->lock);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ return IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_LIGHT:
+ *val = 1;
+ *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2;
+ return IIO_VAL_FRACTIONAL_LOG2;
+
+ default:
+ return -EINVAL;
+ }
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info max44000_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = max44000_read_raw,
+};
+
+static bool max44000_readable_reg(struct device *dev, unsigned int reg)
+{
+ return (1 << reg) & MAX44000_REGMASK_READABLE;
+}
+
+static bool max44000_writeable_reg(struct device *dev, unsigned int reg)
+{
+ return (1 << reg) & MAX44000_REGMASK_WRITEABLE;
+}
+
+static bool max44000_volatile_reg(struct device *dev, unsigned int reg)
+{
+ return (1 << reg) & MAX44000_REGMASK_VOLATILE;
+}
+
+static bool max44000_precious_reg(struct device *dev, unsigned int reg)
+{
+ return reg == MAX44000_REG_STATUS;
+}
+
+/* Datasheet pages 9-10: */
+static const struct reg_default max44000_reg_defaults[] = {
+ { MAX44000_REG_CFG_MAIN, 0x24 },
+ { MAX44000_REG_CFG_RX, MAX44000_REG_CFG_RX_DEFAULT },
+ { MAX44000_REG_CFG_TX, 0x00 },
+ { MAX44000_REG_ALS_UPTHR_HI, 0x00 },
+ { MAX44000_REG_ALS_UPTHR_LO, 0x00 },
+ { MAX44000_REG_ALS_LOTHR_HI, 0x00 },
+ { MAX44000_REG_ALS_LOTHR_LO, 0x00 },
+ { MAX44000_REG_PST, 0x00 },
+ { MAX44000_REG_PRX_IND, 0x00 },
+ { MAX44000_REG_PRX_THR, 0x00 },
+ { MAX44000_REG_TRIM_GAIN_GREEN, 0x80 },
+ { MAX44000_REG_TRIM_GAIN_IR, 0x80 },
+};
+
+static const struct regmap_config max44000_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+
+ .max_register = MAX44000_REG_PRX_DATA,
+ .readable_reg = max44000_readable_reg,
+ .writeable_reg = max44000_writeable_reg,
+ .volatile_reg = max44000_volatile_reg,
+ .precious_reg = max44000_precious_reg,
+
+ .use_single_rw = 1,
+ .cache_type = REGCACHE_FLAT,
+
+ .reg_defaults = max44000_reg_defaults,
+ .num_reg_defaults = ARRAY_SIZE(max44000_reg_defaults),
+};
+
+static int max44000_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct max44000_data *data;
+ struct iio_dev *indio_dev;
+ int ret, reg;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (!indio_dev)
+ return -ENOMEM;
+ data = iio_priv(indio_dev);
+ data->regmap = devm_regmap_init_i2c(client, &max44000_regmap_config);
+ if (IS_ERR(data->regmap)) {
+ dev_err(&client->dev, "regmap_init failed!\n");
+ return PTR_ERR(data->regmap);
+ }
+
+ i2c_set_clientdata(client, indio_dev);
+ mutex_init(&data->lock);
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &max44000_info;
+ indio_dev->name = MAX44000_DRV_NAME;
+ indio_dev->channels = max44000_channels;
+ indio_dev->num_channels = ARRAY_SIZE(max44000_channels);
+
+ /*
+ * The device doesn't have a reset function so we just clear some
+ * important bits at probe time to ensure sane operation.
+ *
+ * Since we don't support interrupts/events the threshold values are
+ * not important. We also don't touch trim values.
+ */
+
+ /* Reset ALS scaling bits */
+ ret = regmap_write(data->regmap, MAX44000_REG_CFG_RX, MAX44000_REG_CFG_RX_DEFAULT);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to write default CFG_RX: %d\n", ret);
+ return ret;
+ }
+
+ /* Reset CFG bits to ALS-only mode and no interrupts */
+ reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_GIR;
+ ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to write init config: %d\n", ret);
+ return ret;
+ }
+
+ /* Read status at least once to clear any stale interrupt bits. */
+ ret = regmap_read(data->regmap, MAX44000_REG_STATUS, &reg);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to read init status: %d\n", ret);
+ return ret;
+ }
+
+ return iio_device_register(indio_dev);
+}
+
+static int max44000_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+ iio_device_unregister(indio_dev);
+ return 0;
+}
+
+static const struct i2c_device_id max44000_id[] = {
+ {"max44000", 0},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, max44000_id);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id max44000_acpi_match[] = {
+ {"MAX44000", 0},
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, max44000_acpi_match);
+#endif
+
+static struct i2c_driver max44000_driver = {
+ .driver = {
+ .name = MAX44000_DRV_NAME,
+ .acpi_match_table = ACPI_PTR(max44000_acpi_match),
+ },
+ .probe = max44000_probe,
+ .remove = max44000_remove,
+ .id_table = max44000_id,
+};
+
+module_i2c_driver(max44000_driver);
+
+MODULE_AUTHOR("Crestez Dan Leonard <leonard.crestez@xxxxxxxxx>");
+MODULE_DESCRIPTION("MAX44000 Ambient and Infrared Proximity Sensor");
+MODULE_LICENSE("GPL v2");
--
2.5.5