Linux-libre 4.2-gnu

1 files changed, 588 insertions, 0 deletions

diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
new file mode 100644
index 000000000..706ebfd62
--- /dev/null
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -0,0 +1,588 @@
+/*
+ * MMC35240 - MEMSIC 3-axis Magnetic Sensor
+ *
+ * Copyright (c) 2015, 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.
+ *
+ * IIO driver for MMC35240 (7-bit I2C slave address 0x30).
+ *
+ * TODO: offset, ACPI, continuous measurement mode, PM
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/regmap.h>
+#include <linux/acpi.h>
+#include <linux/pm.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define MMC35240_DRV_NAME "mmc35240"
+#define MMC35240_REGMAP_NAME "mmc35240_regmap"
+
+#define MMC35240_REG_XOUT_L	0x00
+#define MMC35240_REG_XOUT_H	0x01
+#define MMC35240_REG_YOUT_L	0x02
+#define MMC35240_REG_YOUT_H	0x03
+#define MMC35240_REG_ZOUT_L	0x04
+#define MMC35240_REG_ZOUT_H	0x05
+
+#define MMC35240_REG_STATUS	0x06
+#define MMC35240_REG_CTRL0	0x07
+#define MMC35240_REG_CTRL1	0x08
+
+#define MMC35240_REG_ID		0x20
+
+#define MMC35240_STATUS_MEAS_DONE_BIT	BIT(0)
+
+#define MMC35240_CTRL0_REFILL_BIT	BIT(7)
+#define MMC35240_CTRL0_RESET_BIT	BIT(6)
+#define MMC35240_CTRL0_SET_BIT		BIT(5)
+#define MMC35240_CTRL0_CMM_BIT		BIT(1)
+#define MMC35240_CTRL0_TM_BIT		BIT(0)
+
+/* output resolution bits */
+#define MMC35240_CTRL1_BW0_BIT		BIT(0)
+#define MMC35240_CTRL1_BW1_BIT		BIT(1)
+
+#define MMC35240_CTRL1_BW_MASK	 (MMC35240_CTRL1_BW0_BIT | \
+		 MMC35240_CTRL1_BW1_BIT)
+#define MMC35240_CTRL1_BW_SHIFT		0
+
+#define MMC35240_WAIT_CHARGE_PUMP	50000	/* us */
+#define MMC53240_WAIT_SET_RESET		1000	/* us */
+
+/*
+ * Memsic OTP process code piece is put here for reference:
+ *
+ * #define OTP_CONVERT(REG)  ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006
+ * 1) For X axis, the COEFFICIENT is always 1.
+ * 2) For Y axis, the COEFFICIENT is as below:
+ *    f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) |
+ *                                   (reg_data[2] >> 4)) + 1.0;
+ * 3) For Z axis, the COEFFICIENT is as below:
+ *    f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35;
+ * We implemented the OTP logic into driver.
+ */
+
+/* scale = 1000 here for Y otp */
+#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6)
+
+/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */
+#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81)
+
+#define MMC35240_X_COEFF(x)	(x)
+#define MMC35240_Y_COEFF(y)	(y + 1000)
+#define MMC35240_Z_COEFF(z)	(z + 13500)
+
+#define MMC35240_OTP_START_ADDR		0x1B
+
+enum mmc35240_resolution {
+	MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
+	MMC35240_16_BITS_FAST,     /* 4.08 ms */
+	MMC35240_14_BITS,          /* 2.16 ms */
+	MMC35240_12_BITS,          /* 1.20 ms */
+};
+
+enum mmc35240_axis {
+	AXIS_X = 0,
+	AXIS_Y,
+	AXIS_Z,
+};
+
+static const struct {
+	int sens[3]; /* sensitivity per X, Y, Z axis */
+	int nfo; /* null field output */
+} mmc35240_props_table[] = {
+	/* 16 bits, 125Hz ODR */
+	{
+		{1024, 1024, 1024},
+		32768,
+	},
+	/* 16 bits, 250Hz ODR */
+	{
+		{1024, 1024, 770},
+		32768,
+	},
+	/* 14 bits, 450Hz ODR */
+	{
+		{256, 256, 193},
+		8192,
+	},
+	/* 12 bits, 800Hz ODR */
+	{
+		{64, 64, 48},
+		2048,
+	},
+};
+
+struct mmc35240_data {
+	struct i2c_client *client;
+	struct mutex mutex;
+	struct regmap *regmap;
+	enum mmc35240_resolution res;
+
+	/* OTP compensation */
+	int axis_coef[3];
+	int axis_scale[3];
+};
+
+static const struct {
+	int val;
+	int val2;
+} mmc35240_samp_freq[] = { {1, 500000},
+			   {13, 0},
+			   {25, 0},
+			   {50, 0} };
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("1.5 13 25 50");
+
+#define MMC35240_CHANNEL(_axis) { \
+	.type = IIO_MAGN, \
+	.modified = 1, \
+	.channel2 = IIO_MOD_ ## _axis, \
+	.address = AXIS_ ## _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), \
+}
+
+static const struct iio_chan_spec mmc35240_channels[] = {
+	MMC35240_CHANNEL(X),
+	MMC35240_CHANNEL(Y),
+	MMC35240_CHANNEL(Z),
+};
+
+static struct attribute *mmc35240_attributes[] = {
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group mmc35240_attribute_group = {
+	.attrs = mmc35240_attributes,
+};
+
+static int mmc35240_get_samp_freq_index(struct mmc35240_data *data,
+					int val, int val2)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++)
+		if (mmc35240_samp_freq[i].val == val &&
+		    mmc35240_samp_freq[i].val2 == val2)
+			return i;
+	return -EINVAL;
+}
+
+static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
+{
+	int ret;
+	u8 coil_bit;
+
+	/*
+	 * Recharge the capacitor at VCAP pin, requested to be issued
+	 * before a SET/RESET command.
+	 */
+	ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
+				 MMC35240_CTRL0_REFILL_BIT,
+				 MMC35240_CTRL0_REFILL_BIT);
+	if (ret < 0)
+		return ret;
+	usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1);
+
+	if (set)
+		coil_bit = MMC35240_CTRL0_SET_BIT;
+	else
+		coil_bit = MMC35240_CTRL0_RESET_BIT;
+
+	return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0,
+				  coil_bit, coil_bit);
+
+}
+
+static int mmc35240_init(struct mmc35240_data *data)
+{
+	int ret, y_convert, z_convert;
+	unsigned int reg_id;
+	u8 otp_data[6];
+
+	ret = regmap_read(data->regmap, MMC35240_REG_ID, &reg_id);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Error reading product id\n");
+		return ret;
+	}
+
+	dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
+
+	/*
+	 * make sure we restore sensor characteristics, by doing
+	 * a SET/RESET sequence, the axis polarity being naturally
+	 * aligned after RESET
+	 */
+	ret = mmc35240_hw_set(data, true);
+	if (ret < 0)
+		return ret;
+	usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1);
+
+	ret = mmc35240_hw_set(data, false);
+	if (ret < 0)
+		return ret;
+
+	/* set default sampling frequency */
+	ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
+				 MMC35240_CTRL1_BW_MASK,
+				 data->res << MMC35240_CTRL1_BW_SHIFT);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
+			       (u8 *)otp_data, sizeof(otp_data));
+	if (ret < 0)
+		return ret;
+
+	y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) |
+					   (otp_data[2] >> 4));
+	z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f);
+
+	data->axis_coef[0] = MMC35240_X_COEFF(1);
+	data->axis_coef[1] = MMC35240_Y_COEFF(y_convert);
+	data->axis_coef[2] = MMC35240_Z_COEFF(z_convert);
+
+	data->axis_scale[0] = 1;
+	data->axis_scale[1] = 1000;
+	data->axis_scale[2] = 10000;
+
+	return 0;
+}
+
+static int mmc35240_take_measurement(struct mmc35240_data *data)
+{
+	int ret, tries = 100;
+	unsigned int reg_status;
+
+	ret = regmap_write(data->regmap, MMC35240_REG_CTRL0,
+			   MMC35240_CTRL0_TM_BIT);
+	if (ret < 0)
+		return ret;
+
+	while (tries-- > 0) {
+		ret = regmap_read(data->regmap, MMC35240_REG_STATUS,
+				  &reg_status);
+		if (ret < 0)
+			return ret;
+		if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT)
+			break;
+		/* minimum wait time to complete measurement is 10 ms */
+		usleep_range(10000, 11000);
+	}
+
+	if (tries < 0) {
+		dev_err(&data->client->dev, "data not ready\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
+{
+	int ret;
+
+	ret = mmc35240_take_measurement(data);
+	if (ret < 0)
+		return ret;
+
+	return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf,
+				3 * sizeof(__le16));
+}
+
+/**
+ * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
+			    compensation for output value.
+ *
+ * @data: device private data
+ * @index: axis index for which we want the conversion
+ * @buf: raw data to be converted, 2 bytes in little endian format
+ * @val: compensated output reading (unit is milli gauss)
+ *
+ * Returns: 0 in case of success, -EINVAL when @index is not valid
+ */
+static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
+				  __le16 buf[], int *val)
+{
+	int raw_x, raw_y, raw_z;
+	int sens_x, sens_y, sens_z;
+	int nfo;
+
+	raw_x = le16_to_cpu(buf[AXIS_X]);
+	raw_y = le16_to_cpu(buf[AXIS_Y]);
+	raw_z = le16_to_cpu(buf[AXIS_Z]);
+
+	sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
+	sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
+	sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
+
+	nfo = mmc35240_props_table[data->res].nfo;
+
+	switch (index) {
+	case AXIS_X:
+		*val = (raw_x - nfo) * 1000 / sens_x;
+		break;
+	case AXIS_Y:
+		*val = (raw_y - nfo) * 1000 / sens_y -
+			(raw_z - nfo)  * 1000 / sens_z;
+		break;
+	case AXIS_Z:
+		*val = (raw_y - nfo) * 1000 / sens_y +
+			(raw_z - nfo) * 1000 / sens_z;
+		break;
+	default:
+		return -EINVAL;
+	}
+	/* apply OTP compensation */
+	*val = (*val) * data->axis_coef[index] / data->axis_scale[index];
+
+	return 0;
+}
+
+static int mmc35240_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan, int *val,
+			     int *val2, long mask)
+{
+	struct mmc35240_data *data = iio_priv(indio_dev);
+	int ret, i;
+	unsigned int reg;
+	__le16 buf[3];
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&data->mutex);
+		ret = mmc35240_read_measurement(data, buf);
+		mutex_unlock(&data->mutex);
+		if (ret < 0)
+			return ret;
+		ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
+		if (ret < 0)
+			return ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		*val2 = 1000;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		mutex_lock(&data->mutex);
+		ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, &reg);
+		mutex_unlock(&data->mutex);
+		if (ret < 0)
+			return ret;
+
+		i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT;
+		if (i < 0 || i >= ARRAY_SIZE(mmc35240_samp_freq))
+			return -EINVAL;
+
+		*val = mmc35240_samp_freq[i].val;
+		*val2 = mmc35240_samp_freq[i].val2;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mmc35240_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan, int val,
+			      int val2, long mask)
+{
+	struct mmc35240_data *data = iio_priv(indio_dev);
+	int i, ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		i = mmc35240_get_samp_freq_index(data, val, val2);
+		if (i < 0)
+			return -EINVAL;
+		mutex_lock(&data->mutex);
+		ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1,
+					 MMC35240_CTRL1_BW_MASK,
+					 i << MMC35240_CTRL1_BW_SHIFT);
+		mutex_unlock(&data->mutex);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info mmc35240_info = {
+	.driver_module	= THIS_MODULE,
+	.read_raw	= mmc35240_read_raw,
+	.write_raw	= mmc35240_write_raw,
+	.attrs		= &mmc35240_attribute_group,
+};
+
+static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MMC35240_REG_CTRL0:
+	case MMC35240_REG_CTRL1:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MMC35240_REG_XOUT_L:
+	case MMC35240_REG_XOUT_H:
+	case MMC35240_REG_YOUT_L:
+	case MMC35240_REG_YOUT_H:
+	case MMC35240_REG_ZOUT_L:
+	case MMC35240_REG_ZOUT_H:
+	case MMC35240_REG_STATUS:
+	case MMC35240_REG_ID:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MMC35240_REG_CTRL0:
+	case MMC35240_REG_CTRL1:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static struct reg_default mmc35240_reg_defaults[] = {
+	{ MMC35240_REG_CTRL0,  0x00 },
+	{ MMC35240_REG_CTRL1,  0x00 },
+};
+
+static const struct regmap_config mmc35240_regmap_config = {
+	.name = MMC35240_REGMAP_NAME,
+
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = MMC35240_REG_ID,
+	.cache_type = REGCACHE_FLAT,
+
+	.writeable_reg = mmc35240_is_writeable_reg,
+	.readable_reg = mmc35240_is_readable_reg,
+	.volatile_reg = mmc35240_is_volatile_reg,
+
+	.reg_defaults = mmc35240_reg_defaults,
+	.num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
+};
+
+static int mmc35240_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct mmc35240_data *data;
+	struct iio_dev *indio_dev;
+	struct regmap *regmap;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "regmap initialization failed\n");
+		return PTR_ERR(regmap);
+	}
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	data->client = client;
+	data->regmap = regmap;
+	data->res = MMC35240_16_BITS_SLOW;
+
+	mutex_init(&data->mutex);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &mmc35240_info;
+	indio_dev->name = MMC35240_DRV_NAME;
+	indio_dev->channels = mmc35240_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = mmc35240_init(data);
+	if (ret < 0) {
+		dev_err(&client->dev, "mmc35240 chip init failed\n");
+		return ret;
+	}
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mmc35240_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct mmc35240_data *data = iio_priv(indio_dev);
+
+	regcache_cache_only(data->regmap, true);
+
+	return 0;
+}
+
+static int mmc35240_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct mmc35240_data *data = iio_priv(indio_dev);
+	int ret;
+
+	regcache_mark_dirty(data->regmap);
+	ret = regcache_sync_region(data->regmap, MMC35240_REG_CTRL0,
+				   MMC35240_REG_CTRL1);
+	if (ret < 0)
+		dev_err(dev, "Failed to restore control registers\n");
+
+	regcache_cache_only(data->regmap, false);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops mmc35240_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
+};
+
+static const struct acpi_device_id mmc35240_acpi_match[] = {
+	{"MMC35240", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
+
+static const struct i2c_device_id mmc35240_id[] = {
+	{"mmc35240", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, mmc35240_id);
+
+static struct i2c_driver mmc35240_driver = {
+	.driver = {
+		.name = MMC35240_DRV_NAME,
+		.pm = &mmc35240_pm_ops,
+		.acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
+	},
+	.probe		= mmc35240_probe,
+	.id_table	= mmc35240_id,
+};
+
+module_i2c_driver(mmc35240_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver");
+MODULE_LICENSE("GPL v2");