iio: accel: Add driver for dmard10 3-axis Accelerometer

Add a driver for the Domintech ARD10 3-axis Accelerometer, based on the
android driver found here: https://github.com/domintech/dmard10

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 266 insertions, 0 deletions

diff --git a/drivers/iio/accel/dmard10.c b/drivers/iio/accel/dmard10.c
new file mode 100644
index 000000000000..b8736cc75656
--- /dev/null
+++ b/drivers/iio/accel/dmard10.c
@@ -0,0 +1,266 @@
+/**
+ * IIO driver for the 3-axis accelerometer Domintech ARD10.
+ *
+ * Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
+ * Copyright (c) 2012 Domintech Technology Co., Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/byteorder/generic.h>
+
+#define DMARD10_REG_ACTR			0x00
+#define DMARD10_REG_AFEM			0x0c
+#define DMARD10_REG_STADR			0x12
+#define DMARD10_REG_STAINT			0x1c
+#define DMARD10_REG_MISC2			0x1f
+#define DMARD10_REG_PD				0x21
+
+#define DMARD10_MODE_OFF			0x00
+#define DMARD10_MODE_STANDBY			0x02
+#define DMARD10_MODE_ACTIVE			0x06
+#define DMARD10_MODE_READ_OTP			0x12
+#define DMARD10_MODE_RESET_DATA_PATH		0x82
+
+/* AFEN set 1, ATM[2:0]=b'000 (normal), EN_Z/Y/X/T=1 */
+#define DMARD10_VALUE_AFEM_AFEN_NORMAL		0x8f
+/* ODR[3:0]=b'0111 (100Hz), CCK[3:0]=b'0100 (204.8kHZ) */
+#define DMARD10_VALUE_CKSEL_ODR_100_204		0x74
+/* INTC[6:5]=b'00 */
+#define DMARD10_VALUE_INTC			0x00
+/* TAP1/TAP2 Average 2 */
+#define DMARD10_VALUE_TAPNS_AVE_2		0x11
+
+#define DMARD10_VALUE_STADR			0x55
+#define DMARD10_VALUE_STAINT			0xaa
+#define DMARD10_VALUE_MISC2_OSCA_EN		0x08
+#define DMARD10_VALUE_PD_RST			0x52
+
+/* Offsets into the buffer read in dmard10_read_raw() */
+#define DMARD10_X_OFFSET			1
+#define DMARD10_Y_OFFSET			2
+#define DMARD10_Z_OFFSET			3
+
+/*
+ * a value of + or -128 corresponds to + or - 1G
+ * scale = 9.81 / 128 = 0.076640625
+ */
+
+static const int dmard10_nscale = 76640625;
+
+#define DMARD10_CHANNEL(reg, axis) {	\
+	.type = IIO_ACCEL,	\
+	.address = reg,	\
+	.modified = 1,	\
+	.channel2 = IIO_MOD_##axis,	\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+}
+
+static const struct iio_chan_spec dmard10_channels[] = {
+	DMARD10_CHANNEL(DMARD10_X_OFFSET, X),
+	DMARD10_CHANNEL(DMARD10_Y_OFFSET, Y),
+	DMARD10_CHANNEL(DMARD10_Z_OFFSET, Z),
+};
+
+struct dmard10_data {
+	struct i2c_client *client;
+};
+
+/* Init sequence taken from the android driver */
+static int dmard10_reset(struct i2c_client *client)
+{
+	unsigned char buffer[7];
+	int ret;
+
+	/* 1. Powerdown reset */
+	ret = i2c_smbus_write_byte_data(client, DMARD10_REG_PD,
+						DMARD10_VALUE_PD_RST);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * 2. ACTR => Standby mode => Download OTP to parameter reg =>
+	 *    Standby mode => Reset data path => Standby mode
+	 */
+	buffer[0] = DMARD10_REG_ACTR;
+	buffer[1] = DMARD10_MODE_STANDBY;
+	buffer[2] = DMARD10_MODE_READ_OTP;
+	buffer[3] = DMARD10_MODE_STANDBY;
+	buffer[4] = DMARD10_MODE_RESET_DATA_PATH;
+	buffer[5] = DMARD10_MODE_STANDBY;
+	ret = i2c_master_send(client, buffer, 6);
+	if (ret < 0)
+		return ret;
+
+	/* 3. OSCA_EN = 1, TSTO = b'000 (INT1 = normal, TEST0 = normal) */
+	ret = i2c_smbus_write_byte_data(client, DMARD10_REG_MISC2,
+						DMARD10_VALUE_MISC2_OSCA_EN);
+	if (ret < 0)
+		return ret;
+
+	/* 4. AFEN = 1 (AFE will powerdown after ADC) */
+	buffer[0] = DMARD10_REG_AFEM;
+	buffer[1] = DMARD10_VALUE_AFEM_AFEN_NORMAL;
+	buffer[2] = DMARD10_VALUE_CKSEL_ODR_100_204;
+	buffer[3] = DMARD10_VALUE_INTC;
+	buffer[4] = DMARD10_VALUE_TAPNS_AVE_2;
+	buffer[5] = 0x00; /* DLYC, no delay timing */
+	buffer[6] = 0x07; /* INTD=1 push-pull, INTA=1 active high, AUTOT=1 */
+	ret = i2c_master_send(client, buffer, 7);
+	if (ret < 0)
+		return ret;
+
+	/* 5. Activation mode */
+	ret = i2c_smbus_write_byte_data(client, DMARD10_REG_ACTR,
+						DMARD10_MODE_ACTIVE);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+/* Shutdown sequence taken from the android driver */
+static int dmard10_shutdown(struct i2c_client *client)
+{
+	unsigned char buffer[3];
+
+	buffer[0] = DMARD10_REG_ACTR;
+	buffer[1] = DMARD10_MODE_STANDBY;
+	buffer[2] = DMARD10_MODE_OFF;
+
+	return i2c_master_send(client, buffer, 3);
+}
+
+static int dmard10_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long mask)
+{
+	struct dmard10_data *data = iio_priv(indio_dev);
+	__le16 buf[4];
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		/*
+		 * Read 8 bytes starting at the REG_STADR register, trying to
+		 * read the individual X, Y, Z registers will always read 0.
+		 */
+		ret = i2c_smbus_read_i2c_block_data(data->client,
+						    DMARD10_REG_STADR,
+						    sizeof(buf), (u8 *)buf);
+		if (ret < 0)
+			return ret;
+		ret = le16_to_cpu(buf[chan->address]);
+		*val = sign_extend32(ret, 12);
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		*val2 = dmard10_nscale;
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info dmard10_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= dmard10_read_raw,
+};
+
+static int dmard10_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	int ret;
+	struct iio_dev *indio_dev;
+	struct dmard10_data *data;
+
+	/* These 2 registers have special POR reset values used for id */
+	ret = i2c_smbus_read_byte_data(client, DMARD10_REG_STADR);
+	if (ret != DMARD10_VALUE_STADR)
+		return (ret < 0) ? ret : -ENODEV;
+
+	ret = i2c_smbus_read_byte_data(client, DMARD10_REG_STAINT);
+	if (ret != DMARD10_VALUE_STAINT)
+		return (ret < 0) ? ret : -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev) {
+		dev_err(&client->dev, "iio allocation failed!\n");
+		return -ENOMEM;
+	}
+
+	data = iio_priv(indio_dev);
+	data->client = client;
+	i2c_set_clientdata(client, indio_dev);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &dmard10_info;
+	indio_dev->name = "dmard10";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = dmard10_channels;
+	indio_dev->num_channels = ARRAY_SIZE(dmard10_channels);
+
+	ret = dmard10_reset(client);
+	if (ret < 0)
+		return ret;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "device_register failed\n");
+		dmard10_shutdown(client);
+	}
+
+	return ret;
+}
+
+static int dmard10_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+
+	return dmard10_shutdown(client);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int dmard10_suspend(struct device *dev)
+{
+	return dmard10_shutdown(to_i2c_client(dev));
+}
+
+static int dmard10_resume(struct device *dev)
+{
+	return dmard10_reset(to_i2c_client(dev));
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(dmard10_pm_ops, dmard10_suspend, dmard10_resume);
+
+static const struct i2c_device_id dmard10_i2c_id[] = {
+	{"dmard10", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, dmard10_i2c_id);
+
+static struct i2c_driver dmard10_driver = {
+	.driver = {
+		.name = "dmard10",
+		.pm = &dmard10_pm_ops,
+	},
+	.probe		= dmard10_probe,
+	.remove		= dmard10_remove,
+	.id_table	= dmard10_i2c_id,
+};
+
+module_i2c_driver(dmard10_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("Domintech ARD10 3-Axis Accelerometer driver");
+MODULE_LICENSE("GPL v2");