[PATCH 2/3] iio: adxl372: Add support for I2C communication

[Stefan Popa <stefan.popa@analog.com>]

The adxl372 is designed to communicate in either SPI or I2C protocol. It
autodetects the format being used, requiring no configuration control to
select the format.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
---
 MAINTAINERS                     |  1 +
 drivers/iio/accel/Kconfig       | 11 ++++++++
 drivers/iio/accel/Makefile      |  1 +
 drivers/iio/accel/adxl372.c     |  1 -
 drivers/iio/accel/adxl372.h     |  2 ++
 drivers/iio/accel/adxl372_i2c.c | 61 +++++++++++++++++++++++++++++++++++++++++
 6 files changed, 76 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iio/accel/adxl372_i2c.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 2938632..2b9a364 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -549,6 +549,7 @@ W:	http://ez.analog.com/community/linux-device-drivers
 S:	Supported
 F:	drivers/iio/accel/adxl372.c
 F:	drivers/iio/accel/adxl372_spi.c
+F:	drivers/iio/accel/adxl372_i2c.c
 F:	Documentation/devicetree/bindings/iio/accel/adxl372.txt
 
 AF9013 MEDIA DRIVER
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index bed5da8..7993a67 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -76,6 +76,17 @@ config ADXL372_SPI
 	  To compile this driver as a module, choose M here: the
 	  module will be called adxl372_spi.
 
+config ADXL372_I2C
+	tristate "Analog Devices ADXL372 3-Axis Accelerometer I2C Driver"
+	depends on I2C
+	select ADXL372
+	select REGMAP_I2C
+	help
+	  Say yes here to add support for the Analog Devices ADXL372 triaxial
+	  acceleration sensor.
+	  To compile this driver as a module, choose M here: the
+	  module will be called adxl372_i2c.
+
 config BMA180
 	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"
 	depends on I2C
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index c9c5db9..56bd021 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_ADXL345) += adxl345_core.o
 obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
 obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
 obj-$(CONFIG_ADXL372) += adxl372.o
+obj-$(CONFIG_ADXL372_I2C) += adxl372_i2c.o
 obj-$(CONFIG_ADXL372_SPI) += adxl372_spi.o
 obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_BMA220) += bma220_spi.o
diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
index f1df89d..3b84cb2 100644
--- a/drivers/iio/accel/adxl372.c
+++ b/drivers/iio/accel/adxl372.c
@@ -26,7 +26,6 @@
 #define ADXL372_DEVID			0x00
 #define ADXL372_DEVID_MST		0x01
 #define ADXL372_PARTID			0x02
-#define ADXL372_REVID			0x03
 #define ADXL372_STATUS_1		0x04
 #define ADXL372_STATUS_2		0x05
 #define ADXL372_FIFO_ENTRIES_2		0x06
diff --git a/drivers/iio/accel/adxl372.h b/drivers/iio/accel/adxl372.h
index 5da89b1..80a0aa9 100644
--- a/drivers/iio/accel/adxl372.h
+++ b/drivers/iio/accel/adxl372.h
@@ -8,6 +8,8 @@
 #ifndef _ADXL372_H_
 #define _ADXL372_H_
 
+#define ADXL372_REVID	0x03
+
 int adxl372_probe(struct device *dev, struct regmap *regmap,
 		  int irq, const char *name);
 bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg);
diff --git a/drivers/iio/accel/adxl372_i2c.c b/drivers/iio/accel/adxl372_i2c.c
new file mode 100644
index 0000000..e1affe4
--- /dev/null
+++ b/drivers/iio/accel/adxl372_i2c.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ADXL372 3-Axis Digital Accelerometer I2C driver
+ *
+ * Copyright 2018 Analog Devices Inc.
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "adxl372.h"
+
+static const struct regmap_config adxl372_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.readable_noinc_reg = adxl372_readable_noinc_reg,
+};
+
+static int adxl372_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct regmap *regmap;
+	unsigned int regval;
+	int ret;
+
+	regmap = devm_regmap_init_i2c(client, &adxl372_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	ret = regmap_read(regmap, ADXL372_REVID, &regval);
+	if (ret < 0)
+		return ret;
+
+	/* Starting with the 3rd revision an I2C chip bug was fixed */
+	if (regval < 3)
+		dev_warn(&client->dev,
+		"I2C might not work properly with other devices on the bus");
+
+	return adxl372_probe(&client->dev, regmap, client->irq, id->name);
+}
+
+static const struct i2c_device_id adxl372_i2c_id[] = {
+	{ "adxl372", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, adxl372_i2c_id);
+
+static struct i2c_driver adxl372_i2c_driver = {
+	.driver = {
+		.name = "adxl372_i2c",
+	},
+	.probe = adxl372_i2c_probe,
+	.id_table = adxl372_i2c_id,
+};
+
+module_i2c_driver(adxl372_i2c_driver);
+
+MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
+MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer I2C driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4