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.kepplin...@theobroma-systems.com>
Signed-off-by: Christoph Muellner <christoph.muell...@theobroma-systems.com>
---
 drivers/iio/accel/mma8452.c | 161 ++++++++++++++++++++++++++++++--------------
 1 file changed, 110 insertions(+), 51 deletions(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index e8e2077..b2ebfcb 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -23,7 +23,9 @@
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/events.h>
 #include <linux/delay.h>
+#include <linux/of_device.h>
 
+#define DRIVER_NAME "mma8452"
 #define MMA8452_STATUS 0x00
 #define MMA8452_OUT_X 0x01 /* MSB first, 12-bit  */
 #define MMA8452_OUT_Y 0x03
@@ -78,6 +80,25 @@ struct mma8452_data {
        struct mutex lock;
        u8 ctrl_reg1;
        u8 data_cfg;
+       const struct mma_chip_info *chip_info;
+};
+
+struct mma_chip_info {
+       u8 chip_id;
+       const struct iio_chan_spec *channels;
+       int num_channels;
+       /* 3 modes: 2g, 4g, 8g; 2 ints: m/s^2 and micro m/s^2 */
+       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 +164,6 @@ 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,
@@ -187,8 +198,11 @@ static ssize_t mma8452_show_samp_freq_avail(struct device 
*dev,
 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,
@@ -219,8 +233,8 @@ 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,
@@ -229,7 +243,7 @@ static int mma8452_get_hp_filter_index(struct mma8452_data 
*data,
        int i = mma8452_get_odr_index(data);
 
        return mma8452_get_int_plus_micros_index(mma8452_hp_filter_cutoff[i],
-               ARRAY_SIZE(mma8452_scales[0]), val, val2);
+               ARRAY_SIZE(data->chip_info->mma_scales[0]), val, val2);
 }
 
 static int mma8452_read_hp_filter(struct mma8452_data *data, int *hz, int *uHz)
@@ -266,13 +280,14 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
                mutex_unlock(&data->lock);
                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:
                i = mma8452_get_odr_index(data);
@@ -420,16 +435,16 @@ 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;
 
@@ -472,8 +487,11 @@ static int mma8452_write_thresh(struct iio_dev *indio_dev,
 
        switch (info) {
        case IIO_EV_INFO_VALUE:
-               return mma8452_change_config(data, MMA8452_TRANSIENT_THS,
-                                            val & MMA8452_TRANSIENT_THS_MASK);
+               if (val < 0 || val > 127) /* LSB 0.6178 m/s^2 */
+                       return -EINVAL;
+
+               return mma8452_change_config(data, data->chip_info->ev_ths,
+                                            val);
 
        case IIO_EV_INFO_PERIOD:
                steps = (val * USEC_PER_SEC + val2) /
@@ -483,7 +501,7 @@ static int mma8452_write_thresh(struct iio_dev *indio_dev,
                if (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:
                reg = i2c_smbus_read_byte_data(data->client,
@@ -512,13 +530,15 @@ 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) ? 1 : 0;
 }
 
 static int mma8452_write_event_config(struct iio_dev *indio_dev,
@@ -528,20 +548,21 @@ 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)
@@ -550,25 +571,25 @@ 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_THRESH,
                                                  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_THRESH,
                                                  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_THRESH,
@@ -669,7 +690,7 @@ 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, \
@@ -681,9 +702,9 @@ 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, \
@@ -691,12 +712,42 @@ 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,
+};
+
+/*
+ * 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 is given by:
+ *     g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
+ */
+
+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),
+               .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,
@@ -813,12 +864,18 @@ 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] },
+       { }
+};
+
 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)
@@ -826,21 +883,28 @@ 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;
 
        data = iio_priv(indio_dev);
        data->client = client;
+       data->chip_info = match->data;
        mutex_init(&data->lock);
 
        i2c_set_clientdata(client, indio_dev);
        indio_dev->info = &mma8452_info;
-       indio_dev->name = id->name;
+       indio_dev->name = DRIVER_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);
@@ -959,19 +1023,14 @@ 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" },
-       { }
-};
-
 static struct i2c_driver mma8452_driver = {
        .driver = {
-               .name   = "mma8452",
+               .name   = DRIVER_NAME,
                .of_match_table = of_match_ptr(mma8452_dt_ids),
                .pm     = MMA8452_PM_OPS,
        },
-- 
2.1.4

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