iio: mma8452: refactor for seperating chip specific data

This adds a struct mma_chip_info to hold data that will remain specific to
the chip in use. It is provided during probe() and linked in
struct of_device_id.

Also this suggests that the driver is called "mma8452" and now handles the
MMA8452Q device, but is not limited to it.
Signed-off-by: Martin Kepplinger <martin.kepplinger@theobroma-systems.com>
Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/mma8452.c

@@ -22,6 +22,7 @@
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/events.h>
 #include <linux/delay.h>
+#include <linux/of_device.h>
 
 #define MMA8452_STATUS				0x00
 #define  MMA8452_STATUS_DRDY			(BIT(2) | BIT(1) | BIT(0))
@@ -74,6 +75,52 @@ struct mma8452_data {
 	struct mutex lock;
 	u8 ctrl_reg1;
 	u8 data_cfg;
+	const struct mma_chip_info *chip_info;
+};
+
+/**
+ * struct mma_chip_info - chip specific data for Freescale's accelerometers
+ * @chip_id:			WHO_AM_I register's value
+ * @channels:			struct iio_chan_spec matching the device's
+ *				capabilities
+ * @num_channels:		number of channels
+ * @mma_scales:			scale factors for converting register values
+ *				to m/s^2; 3 modes: 2g, 4g, 8g; 2 integers
+ *				per mode: m/s^2 and micro m/s^2
+ * @ev_cfg:			event config register address
+ * @ev_cfg_ele:			latch bit in event config register
+ * @ev_cfg_chan_shift:		number of the bit to enable events in X
+ *				direction; in event config register
+ * @ev_src:			event source register address
+ * @ev_src_xe:			bit in event source register that indicates
+ *				an event in X direction
+ * @ev_src_ye:			bit in event source register that indicates
+ *				an event in Y direction
+ * @ev_src_ze:			bit in event source register that indicates
+ *				an event in Z direction
+ * @ev_ths:			event threshold register address
+ * @ev_ths_mask:		mask for the threshold value
+ * @ev_count:			event count (period) register address
+ *
+ * Since not all chips supported by the driver support comparing high pass
+ * filtered data for events (interrupts), different interrupt sources are
+ * used for different chips and the relevant registers are included here.
+ */
+struct mma_chip_info {
+	u8 chip_id;
+	const struct iio_chan_spec *channels;
+	int num_channels;
+	const int mma_scales[3][2];
+	u8 ev_cfg;
+	u8 ev_cfg_ele;
+	u8 ev_cfg_chan_shift;
+	u8 ev_src;
+	u8 ev_src_xe;
+	u8 ev_src_ye;
+	u8 ev_src_ze;
+	u8 ev_ths;
+	u8 ev_ths_mask;
+	u8 ev_count;
 };
 
 static int mma8452_drdy(struct mma8452_data *data)
@@ -143,16 +190,6 @@ static const int mma8452_samp_freq[8][2] = {
 	{6, 250000}, {1, 560000}
 };
 
-/*
- * Hardware has fullscale of -2G, -4G, -8G corresponding to raw value -2048
- * The userspace interface uses m/s^2 and we declare micro units
- * So scale factor is given by:
- *	g * N * 1000000 / 2048 for N = 2, 4, 8 and g = 9.80665
- */
-static const int mma8452_scales[3][2] = {
-	{0, 9577}, {0, 19154}, {0, 38307}
-};
-
 /* Datasheet table 35  (step time vs sample frequency) */
 static const int mma8452_transient_time_step_us[8] = {
 	1250,
@@ -189,8 +226,11 @@ static ssize_t mma8452_show_scale_avail(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
 {
-	return mma8452_show_int_plus_micros(buf, mma8452_scales,
-					    ARRAY_SIZE(mma8452_scales));
+	struct mma8452_data *data = iio_priv(i2c_get_clientdata(
+					     to_i2c_client(dev)));
+
+	return mma8452_show_int_plus_micros(buf, data->chip_info->mma_scales,
+		ARRAY_SIZE(data->chip_info->mma_scales));
 }
 
 static ssize_t mma8452_show_hp_cutoff_avail(struct device *dev,
@@ -221,9 +261,8 @@ static int mma8452_get_samp_freq_index(struct mma8452_data *data,
 
 static int mma8452_get_scale_index(struct mma8452_data *data, int val, int val2)
 {
-	return mma8452_get_int_plus_micros_index(mma8452_scales,
-						 ARRAY_SIZE(mma8452_scales),
-						 val, val2);
+	return mma8452_get_int_plus_micros_index(data->chip_info->mma_scales,
+			ARRAY_SIZE(data->chip_info->mma_scales), val, val2);
 }
 
 static int mma8452_get_hp_filter_index(struct mma8452_data *data,
@@ -270,14 +309,15 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
 		if (ret < 0)
 			return ret;
 
-		*val = sign_extend32(be16_to_cpu(buffer[chan->scan_index]) >> 4,
-				     11);
+		*val = sign_extend32(be16_to_cpu(
+			buffer[chan->scan_index]) >> chan->scan_type.shift,
+			chan->scan_type.realbits - 1);
 
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		i = data->data_cfg & MMA8452_DATA_CFG_FS_MASK;
-		*val = mma8452_scales[i][0];
-		*val2 = mma8452_scales[i][1];
+		*val = data->chip_info->mma_scales[i][0];
+		*val2 = data->chip_info->mma_scales[i][1];
 
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_SAMP_FREQ:
@@ -439,17 +479,17 @@ static int mma8452_read_thresh(struct iio_dev *indio_dev,
 	switch (info) {
 	case IIO_EV_INFO_VALUE:
 		ret = i2c_smbus_read_byte_data(data->client,
-					       MMA8452_TRANSIENT_THS);
+					       data->chip_info->ev_ths);
 		if (ret < 0)
 			return ret;
 
-		*val = ret & MMA8452_TRANSIENT_THS_MASK;
+		*val = ret & data->chip_info->ev_ths_mask;
 
 		return IIO_VAL_INT;
 
 	case IIO_EV_INFO_PERIOD:
 		ret = i2c_smbus_read_byte_data(data->client,
-					       MMA8452_TRANSIENT_COUNT);
+					       data->chip_info->ev_count);
 		if (ret < 0)
 			return ret;
 
@@ -497,7 +537,8 @@ static int mma8452_write_thresh(struct iio_dev *indio_dev,
 		if (val < 0 || val > MMA8452_TRANSIENT_THS_MASK)
 			return -EINVAL;
 
-		return mma8452_change_config(data, MMA8452_TRANSIENT_THS, val);
+		return mma8452_change_config(data, data->chip_info->ev_ths,
+					     val);
 
 	case IIO_EV_INFO_PERIOD:
 		steps = (val * USEC_PER_SEC + val2) /
@@ -507,7 +548,7 @@ static int mma8452_write_thresh(struct iio_dev *indio_dev,
 		if (steps < 0 || steps > 0xff)
 			return -EINVAL;
 
-		return mma8452_change_config(data, MMA8452_TRANSIENT_COUNT,
+		return mma8452_change_config(data, data->chip_info->ev_count,
 					     steps);
 
 	case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
@@ -538,13 +579,15 @@ static int mma8452_read_event_config(struct iio_dev *indio_dev,
 				     enum iio_event_direction dir)
 {
 	struct mma8452_data *data = iio_priv(indio_dev);
+	const struct mma_chip_info *chip = data->chip_info;
 	int ret;
 
-	ret = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_CFG);
+	ret = i2c_smbus_read_byte_data(data->client,
+				       data->chip_info->ev_cfg);
 	if (ret < 0)
 		return ret;
 
-	return ret & MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index) ? 1 : 0;
+	return !!(ret & BIT(chan->scan_index + chip->ev_cfg_chan_shift));
 }
 
 static int mma8452_write_event_config(struct iio_dev *indio_dev,
@@ -554,20 +597,21 @@ static int mma8452_write_event_config(struct iio_dev *indio_dev,
 				      int state)
 {
 	struct mma8452_data *data = iio_priv(indio_dev);
+	const struct mma_chip_info *chip = data->chip_info;
 	int val;
 
-	val = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_CFG);
+	val = i2c_smbus_read_byte_data(data->client, chip->ev_cfg);
 	if (val < 0)
 		return val;
 
 	if (state)
-		val |= MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index);
+		val |= BIT(chan->scan_index + chip->ev_cfg_chan_shift);
 	else
-		val &= ~MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index);
+		val &= ~BIT(chan->scan_index + chip->ev_cfg_chan_shift);
 
 	val |= MMA8452_TRANSIENT_CFG_ELE;
 
-	return mma8452_change_config(data, MMA8452_TRANSIENT_CFG, val);
+	return mma8452_change_config(data, chip->ev_cfg, val);
 }
 
 static void mma8452_transient_interrupt(struct iio_dev *indio_dev)
@@ -576,25 +620,25 @@ static void mma8452_transient_interrupt(struct iio_dev *indio_dev)
 	s64 ts = iio_get_time_ns();
 	int src;
 
-	src = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_SRC);
+	src = i2c_smbus_read_byte_data(data->client, data->chip_info->ev_src);
 	if (src < 0)
 		return;
 
-	if (src & MMA8452_TRANSIENT_SRC_XTRANSE)
+	if (src & data->chip_info->ev_src_xe)
 		iio_push_event(indio_dev,
 			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_X,
 						  IIO_EV_TYPE_MAG,
 						  IIO_EV_DIR_RISING),
 			       ts);
 
-	if (src & MMA8452_TRANSIENT_SRC_YTRANSE)
+	if (src & data->chip_info->ev_src_ye)
 		iio_push_event(indio_dev,
 			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_Y,
 						  IIO_EV_TYPE_MAG,
 						  IIO_EV_DIR_RISING),
 			       ts);
 
-	if (src & MMA8452_TRANSIENT_SRC_ZTRANSE)
+	if (src & data->chip_info->ev_src_ze)
 		iio_push_event(indio_dev,
 			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_Z,
 						  IIO_EV_TYPE_MAG,
@@ -696,7 +740,7 @@ static struct attribute_group mma8452_event_attribute_group = {
 	.name = "events",
 };
 
-#define MMA8452_CHANNEL(axis, idx) { \
+#define MMA8452_CHANNEL(axis, idx, bits) { \
 	.type = IIO_ACCEL, \
 	.modified = 1, \
 	.channel2 = IIO_MOD_##axis, \
@@ -708,9 +752,9 @@ static struct attribute_group mma8452_event_attribute_group = {
 	.scan_index = idx, \
 	.scan_type = { \
 		.sign = 's', \
-		.realbits = 12, \
+		.realbits = (bits), \
 		.storagebits = 16, \
-		.shift = 4, \
+		.shift = 16 - (bits), \
 		.endianness = IIO_BE, \
 	}, \
 	.event_spec = mma8452_transient_event, \
@@ -718,12 +762,42 @@ static struct attribute_group mma8452_event_attribute_group = {
 }
 
 static const struct iio_chan_spec mma8452_channels[] = {
-	MMA8452_CHANNEL(X, 0),
-	MMA8452_CHANNEL(Y, 1),
-	MMA8452_CHANNEL(Z, 2),
+	MMA8452_CHANNEL(X, 0, 12),
+	MMA8452_CHANNEL(Y, 1, 12),
+	MMA8452_CHANNEL(Z, 2, 12),
 	IIO_CHAN_SOFT_TIMESTAMP(3),
 };
 
+enum {
+	mma8452,
+};
+
+static const struct mma_chip_info mma_chip_info_table[] = {
+	[mma8452] = {
+		.chip_id = MMA8452_DEVICE_ID,
+		.channels = mma8452_channels,
+		.num_channels = ARRAY_SIZE(mma8452_channels),
+		/*
+		 * Hardware has fullscale of -2G, -4G, -8G corresponding to
+		 * raw value -2048 for 12 bit or -512 for 10 bit.
+		 * The userspace interface uses m/s^2 and we declare micro units
+		 * So scale factor for 12 bit here is given by:
+		 *	g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
+		 */
+		.mma_scales = { {0, 9577}, {0, 19154}, {0, 38307} },
+		.ev_cfg = MMA8452_TRANSIENT_CFG,
+		.ev_cfg_ele = MMA8452_TRANSIENT_CFG_ELE,
+		.ev_cfg_chan_shift = 1,
+		.ev_src = MMA8452_TRANSIENT_SRC,
+		.ev_src_xe = MMA8452_TRANSIENT_SRC_XTRANSE,
+		.ev_src_ye = MMA8452_TRANSIENT_SRC_YTRANSE,
+		.ev_src_ze = MMA8452_TRANSIENT_SRC_ZTRANSE,
+		.ev_ths = MMA8452_TRANSIENT_THS,
+		.ev_ths_mask = MMA8452_TRANSIENT_THS_MASK,
+		.ev_count = MMA8452_TRANSIENT_COUNT,
+	},
+};
+
 static struct attribute *mma8452_attributes[] = {
 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
 	&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
@@ -841,12 +915,19 @@ static int mma8452_reset(struct i2c_client *client)
 	return -ETIMEDOUT;
 }
 
+static const struct of_device_id mma8452_dt_ids[] = {
+	{ .compatible = "fsl,mma8452", .data = &mma_chip_info_table[mma8452] },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mma8452_dt_ids);
+
 static int mma8452_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct mma8452_data *data;
 	struct iio_dev *indio_dev;
 	int ret;
+	const struct of_device_id *match;
 
 	ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
 	if (ret < 0)
@@ -854,6 +935,12 @@ static int mma8452_probe(struct i2c_client *client,
 	if (ret != MMA8452_DEVICE_ID)
 		return -ENODEV;
 
+	match = of_match_device(mma8452_dt_ids, &client->dev);
+	if (!match) {
+		dev_err(&client->dev, "unknown device model\n");
+		return -ENODEV;
+	}
+
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
@@ -861,14 +948,18 @@ static int mma8452_probe(struct i2c_client *client,
 	data = iio_priv(indio_dev);
 	data->client = client;
 	mutex_init(&data->lock);
+	data->chip_info = match->data;
+
+	dev_info(&client->dev, "registering %s accelerometer; ID 0x%x\n",
+		 match->compatible, data->chip_info->chip_id);
 
 	i2c_set_clientdata(client, indio_dev);
 	indio_dev->info = &mma8452_info;
 	indio_dev->name = id->name;
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->channels = mma8452_channels;
-	indio_dev->num_channels = ARRAY_SIZE(mma8452_channels);
+	indio_dev->channels = data->chip_info->channels;
+	indio_dev->num_channels = data->chip_info->num_channels;
 	indio_dev->available_scan_masks = mma8452_scan_masks;
 
 	ret = mma8452_reset(client);
@@ -987,17 +1078,11 @@ static SIMPLE_DEV_PM_OPS(mma8452_pm_ops, mma8452_suspend, mma8452_resume);
 #endif
 
 static const struct i2c_device_id mma8452_id[] = {
-	{ "mma8452", 0 },
+	{ "mma8452", mma8452 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mma8452_id);
 
-static const struct of_device_id mma8452_dt_ids[] = {
-	{ .compatible = "fsl,mma8452" },
-	{ }
-};
-MODULE_DEVICE_TABLE(of, mma8452_dt_ids);
-
 static struct i2c_driver mma8452_driver = {
 	.driver = {
 		.name	= "mma8452",