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Subject[PATCH 1/6] iio: mma8452: refactor for seperating chip specific data
Date
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>
---
drivers/iio/accel/mma8452.c | 183 ++++++++++++++++++++++++++++++++------------
1 file changed, 134 insertions(+), 49 deletions(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index b921d84..f28428fa 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/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",
--
2.1.4


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