[PATCH v3 4/4] iio: accel: adxl345: Add SPI support

[Eva Rachel Retuya]

Add SPI driver that initializes SPI regmap for the adxl345 core driver.
The driver supports the same functionality as I2C namely the x, y, z and
scale readings.

Signed-off-by: Eva Rachel Retuya <eraretuya@xxxxxxxxx>
---
Change from v2:
* Add OF match table on both I2C and SPI files and document them

 drivers/iio/accel/Kconfig       |  8 +++-
 drivers/iio/accel/Makefile      |  1 +
 drivers/iio/accel/adxl345_spi.c | 86 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 drivers/iio/accel/adxl345_spi.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index ffb0a63..454aeff 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -8,20 +8,26 @@ menu "Accelerometers"
 config ADXL345
 	tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer Driver"
 	depends on !(INPUT_ADXL34X=y || INPUT_ADXL34X=m)
+	depends on (I2C || SPI)
 	select REGMAP
 	select ADXL345_I2C if I2C
+	select ADXL345_SPI if SPI
 	help
 	  Say Y here if you want to build support for the Analog Devices
 	  ADXL345 3-axis digital accelerometer.
 
 	  To compile this driver as a module, choose M here: the core
 	  module will be called adxl345_core and you will also get
-	  adxl345_i2c for I2C.
+	  adxl345_i2c for I2C and/or adxl345_spi for SPI.
 
 config ADXL345_I2C
 	tristate
 	select REGMAP_I2C
 
+config ADXL345_SPI
+	tristate
+	select REGMAP_SPI
+
 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 3f4a6d6..31fba19 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -5,6 +5,7 @@
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_ADXL345) += adxl345_core.o
 obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
+obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
 obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_BMA220) += bma220_spi.o
 obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
new file mode 100644
index 0000000..5b6f01c
--- /dev/null
+++ b/drivers/iio/accel/adxl345_spi.c
@@ -0,0 +1,86 @@
+/*
+ * ADXL345 3-Axis Digital Accelerometer
+ *
+ * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@xxxxxxxxx>
+ *
+ * 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.
+ *
+ * SPI driver for ADXL345
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "adxl345.h"
+
+#define ADXL345_MAX_SPI_FREQ_HZ		5000000
+
+static const struct regmap_config adxl345_spi_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	 /* Setting bits 7 and 6 enables multiple-byte read */
+	.read_flag_mask = BIT(7) | BIT(6),
+};
+
+static int adxl345_spi_probe(struct spi_device *spi)
+{
+	struct regmap *regmap;
+	const struct spi_device_id *id = spi_get_device_id(spi);
+
+	/* Bail out if max_speed_hz exceeds 5 MHz */
+	if (spi->max_speed_hz > ADXL345_MAX_SPI_FREQ_HZ) {
+		dev_err(&spi->dev, "SPI CLK, %d Hz exceeds 5 MHz\n",
+			spi->max_speed_hz);
+		return -EINVAL;
+	}
+
+	regmap = devm_regmap_init_spi(spi, &adxl345_spi_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "Error initializing spi regmap: %d\n",
+			(int)PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	return adxl345_common_probe(&spi->dev, regmap, id->name);
+}
+
+static int adxl345_spi_remove(struct spi_device *spi)
+{
+	return adxl345_common_remove(&spi->dev);
+}
+
+static const struct spi_device_id adxl345_spi_id[] = {
+	{ "adxl345", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(spi, adxl345_spi_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id adxl345_of_match[] = {
+	{ .compatible = "adi,adxl345" },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, adxl345_of_match);
+#endif
+
+static struct spi_driver adxl345_spi_driver = {
+	.driver = {
+		.name	= "adxl345_spi",
+		.of_match_table = of_match_ptr(adxl345_of_match),
+	},
+	.probe		= adxl345_spi_probe,
+	.remove		= adxl345_spi_remove,
+	.id_table	= adxl345_spi_id,
+};
+
+module_spi_driver(adxl345_spi_driver);
+
+MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@xxxxxxxxx>");
+MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer SPI driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4