[PATCH] iio: accel: add Freescale MMA7455L 3-axis accelerometer driver

[Joachim Eastwood <manabian@gmail.com>]

Add support for Freescale MMA7455L 3-axis in 10-bit mode with both
I2C and SPI bus support. This is a rather simple driver that
currently doesn't support all the hardware features of MMA7455L.

Tested on Embedded Artists' LPC4357 Dev Kit using I2C bus.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
---

 drivers/iio/accel/Kconfig   |  14 ++
 drivers/iio/accel/Makefile  |   1 +
 drivers/iio/accel/mma7455.c | 424 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 439 insertions(+)
 create mode 100644 drivers/iio/accel/mma7455.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index a59047d7657e..8ccb3de85484 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -99,6 +99,20 @@ config KXCJK1013
 	  To compile this driver as a module, choose M here: the module will
 	  be called kxcjk-1013.
 
+config MMA7455
+	tristate "Freescale MMA7455L Accelerometer Driver"
+	depends on I2C || SPI_MASTER
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP_I2C if I2C
+	select REGMAP_SPI if SPI_MASTER
+	help
+	  Say yes here to build support for the Freescale MMA7455L 3-axis
+	  accelerometer.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called mma7455.
+
 config MMA8452
 	tristate "Freescale MMA8452Q Accelerometer Driver"
 	depends on I2C
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index ebd2675b2a02..6ac9382761f8 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel.o
 obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
 obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
 obj-$(CONFIG_KXSD9)	+= kxsd9.o
+obj-$(CONFIG_MMA7455)	+= mma7455.o
 obj-$(CONFIG_MMA8452)	+= mma8452.o
 
 obj-$(CONFIG_MMA9551_CORE)	+= mma9551_core.o
diff --git a/drivers/iio/accel/mma7455.c b/drivers/iio/accel/mma7455.c
new file mode 100644
index 000000000000..fa62f2bcb54a
--- /dev/null
+++ b/drivers/iio/accel/mma7455.c
@@ -0,0 +1,424 @@
+/*
+ * mma7455.c - Support for Freescale MMA7455L 3-axis 10-bit accelerometer
+ * Copyright 2015 Joachim Eastwood <manabian@gmail.com>
+ *
+ * Based on MMA8452Q IIO driver
+ * Copyright 2014 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * UNSUPPORTED hardware features:
+ *  - 8-bit mode with different scales
+ *  - INT1/INT2 interrupts
+ *  - Offset calibration
+ *  - Events
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#define MMA7455_REG_XOUTL		0x00
+#define MMA7455_REG_XOUTH		0x01
+#define MMA7455_REG_YOUTL		0x02
+#define MMA7455_REG_YOUTH		0x03
+#define MMA7455_REG_ZOUTL		0x04
+#define MMA7455_REG_ZOUTH		0x05
+#define MMA7455_REG_STATUS		0x09
+#define  MMA7455_STATUS_DRDY		BIT(0)
+#define MMA7455_REG_WHOAMI		0x0f
+#define  MMA7455_WHOAMI_ID		0x55
+#define MMA7455_REG_MCTL		0x16
+#define  MMA7455_MCTL_MODE_STANDBY	0x00
+#define  MMA7455_MCTL_MODE_MEASURE	0x01
+#define MMA7455_REG_CTL1		0x18
+#define  MMA7455_CTL1_DFBW_MASK		BIT(7)
+#define  MMA7455_CTL1_DFBW_125HZ	BIT(7)
+#define  MMA7455_CTL1_DFBW_62_5HZ	0
+#define MMA7455_REG_TW			0x1e
+
+/*
+ * When MMA7455 is used in 10-bit it has a fullscale of -8g
+ * corresponding to raw value -512. The userspace interface
+ * uses m/s^2 and we declare micro units.
+ * So scale factor is given by:
+ *       g * 8 * 1e6 / 512 = 153228.90625, with g = 9.80665
+ */
+#define MMA7455_10BIT_SCALE	153229
+
+struct mma7455_data {
+	struct regmap *regmap;
+	struct device *dev;
+};
+
+static int mma7455_drdy(struct mma7455_data *mma7455)
+{
+	unsigned int reg;
+	int tries = 10;
+	int ret;
+
+	while (tries-- > 0) {
+		ret = regmap_read(mma7455->regmap, MMA7455_REG_STATUS, &reg);
+		if (ret)
+			return ret;
+
+		if (reg & MMA7455_STATUS_DRDY)
+			return 0;
+
+		msleep(20);
+	}
+
+	dev_warn(mma7455->dev, "data not ready\n");
+
+	return -EIO;
+}
+
+static irqreturn_t mma7455_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct mma7455_data *mma7455 = iio_priv(indio_dev);
+	u8 buf[16]; /* 3 x 16-bit channels + padding + ts */
+	int ret;
+
+	ret = mma7455_drdy(mma7455);
+	if (ret)
+		goto done;
+
+	ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf,
+			       sizeof(s16) * 3);
+	if (ret)
+		goto done;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
+
+done:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int mma7455_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct mma7455_data *mma7455 = iio_priv(indio_dev);
+	unsigned int reg = 0;
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (iio_buffer_enabled(indio_dev))
+			return -EBUSY;
+
+		ret = mma7455_drdy(mma7455);
+		if (ret)
+			return ret;
+
+		ret = regmap_bulk_read(mma7455->regmap, chan->scan_index * 2,
+				       &reg, sizeof(s16));
+		if (ret)
+			return ret;
+
+		*val = sign_extend32(reg, 9);
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		*val2 = MMA7455_10BIT_SCALE;
+
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, &reg);
+		if (ret)
+			return ret;
+
+		if (reg & MMA7455_CTL1_DFBW_MASK)
+			*val = 250;
+		else
+			*val = 125;
+
+		return IIO_VAL_INT;
+	}
+
+	return -EINVAL;
+}
+
+static int mma7455_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct mma7455_data *mma7455 = iio_priv(indio_dev);
+	int i;
+
+	if (iio_buffer_enabled(indio_dev))
+		return -EBUSY;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (val == 250)
+			i = MMA7455_CTL1_DFBW_125HZ;
+		else if (val == 125)
+			i = MMA7455_CTL1_DFBW_62_5HZ;
+		else
+			return -EINVAL;
+
+		return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1,
+					  MMA7455_CTL1_DFBW_MASK, i);
+
+	case IIO_CHAN_INFO_SCALE:
+		/* In 10-bit mode there is only one scale available */
+		if (val == 0 && val2 == MMA7455_10BIT_SCALE)
+			return 0;
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t mma7455_show_samp_freq_avail(struct device *dev,
+					    struct device_attribute *attr,
+					    char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "125 250\n");
+}
+
+static ssize_t mma7455_show_scale_avail(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "0.%u\n", MMA7455_10BIT_SCALE);
+}
+
+static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma7455_show_samp_freq_avail);
+static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
+		       mma7455_show_scale_avail, NULL, 0);
+
+static struct attribute *mma7455_attributes[] = {
+	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
+	&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group mma7455_group = {
+	.attrs = mma7455_attributes,
+};
+
+static const struct iio_info mma7455_info = {
+	.attrs = &mma7455_group,
+	.read_raw = mma7455_read_raw,
+	.write_raw = mma7455_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+#define MMA7455_CHANNEL(axis, idx) { \
+	.type = IIO_ACCEL, \
+	.modified = 1, \
+	.channel2 = IIO_MOD_##axis, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
+				    BIT(IIO_CHAN_INFO_SCALE), \
+	.scan_index = idx, \
+	.scan_type = { \
+		.sign = 's', \
+		.realbits = 10, \
+		.storagebits = 16, \
+		.shift = 0, \
+		.endianness = IIO_LE, \
+	}, \
+}
+
+static const struct iio_chan_spec mma7455_channels[] = {
+	MMA7455_CHANNEL(X, 0),
+	MMA7455_CHANNEL(Y, 1),
+	MMA7455_CHANNEL(Z, 2),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+static const unsigned long mma7455_scan_masks[] = {0x7, 0};
+
+static int mma7455_probe(struct device *dev, struct regmap *regmap)
+{
+	struct mma7455_data *mma7455;
+	struct iio_dev *indio_dev;
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(regmap, MMA7455_REG_WHOAMI, &reg);
+	if (ret) {
+		dev_err(dev, "unable to read reg\n");
+		return ret;
+	}
+
+	if (reg != MMA7455_WHOAMI_ID) {
+		dev_err(dev, "device id mismatch\n");
+		return -ENODEV;
+	}
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*mma7455));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, indio_dev);
+	mma7455 = iio_priv(indio_dev);
+	mma7455->regmap = regmap;
+	mma7455->dev = dev;
+
+	indio_dev->info = &mma7455_info;
+	indio_dev->name = "mma7455l";
+	indio_dev->dev.parent = dev;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = mma7455_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mma7455_channels);
+	indio_dev->available_scan_masks = mma7455_scan_masks;
+
+	regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
+		     MMA7455_MCTL_MODE_MEASURE);
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+					 mma7455_trigger_handler, NULL);
+	if (ret) {
+		dev_err(dev, "unable to setup triggered buffer\n");
+		return ret;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(dev, "unable to register device\n");
+		iio_triggered_buffer_cleanup(indio_dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mma7455_remove(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct mma7455_data *mma7455 = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
+		     MMA7455_MCTL_MODE_STANDBY);
+
+	return 0;
+}
+
+static const struct regmap_config mma7455_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MMA7455_REG_TW,
+};
+
+#if IS_ENABLED(CONFIG_SPI_MASTER)
+static int mma7455_spi_probe(struct spi_device *spi)
+{
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_spi(spi, &mma7455_regmap);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return mma7455_probe(&spi->dev, regmap);
+}
+
+static int mma7455_spi_remove(struct spi_device *spi)
+{
+	return mma7455_remove(&spi->dev);
+}
+
+static const struct spi_device_id mma7455_spi_id[] = {
+	{ "mma7455", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, mma7455_spi_id);
+
+static struct spi_driver mma7455_spi_driver = {
+	.probe = mma7455_spi_probe,
+	.remove = mma7455_spi_remove,
+	.id_table = mma7455_spi_id,
+	.driver = {
+		.name = "mma7455-spi",
+	},
+};
+#endif
+
+#if IS_ENABLED(CONFIG_I2C)
+static int mma7455_i2c_probe(struct i2c_client *i2c,
+			     const struct i2c_device_id *id)
+{
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_i2c(i2c, &mma7455_regmap);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return mma7455_probe(&i2c->dev, regmap);
+}
+
+static int mma7455_i2c_remove(struct i2c_client *i2c)
+{
+	return mma7455_remove(&i2c->dev);
+}
+
+static const struct i2c_device_id mma7455_i2c_id[] = {
+	{ "mma7455", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mma7455_i2c_id);
+
+static struct i2c_driver mma7455_i2c_driver = {
+	.probe = mma7455_i2c_probe,
+	.remove = mma7455_i2c_remove,
+	.id_table = mma7455_i2c_id,
+	.driver = {
+		.name	= "mma7455-i2c",
+	},
+};
+#endif
+
+static int __init mma7455_modinit(void)
+{
+	int ret;
+#if IS_ENABLED(CONFIG_I2C)
+	ret = i2c_add_driver(&mma7455_i2c_driver);
+	if (ret)
+		pr_err("failed to register MMA7455L I2C driver: %d\n", ret);
+#endif
+#if IS_ENABLED(CONFIG_SPI_MASTER)
+	ret = spi_register_driver(&mma7455_spi_driver);
+	if (ret)
+		pr_err("failed to register MMA7455L SPI driver: %d\n", ret);
+#endif
+	return ret;
+}
+module_init(mma7455_modinit);
+
+static void __exit mma7455_exit(void)
+{
+#if IS_ENABLED(CONFIG_I2C)
+	i2c_del_driver(&mma7455_i2c_driver);
+#endif
+#if IS_ENABLED(CONFIG_SPI_MASTER)
+	spi_unregister_driver(&mma7455_spi_driver);
+#endif
+}
+module_exit(mma7455_exit);
+
+MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
+MODULE_DESCRIPTION("Freescale MMA7455L I2C/SPI accelerometer driver");
+MODULE_LICENSE("GPL v2");
-- 
1.8.0