Re: [PATCH 1/9] iio: mma8452: refactor for seperating chip specific data

From: Jonathan Cameron
Date: Sun Jul 05 2015 - 07:38:06 EST

On 04/07/15 14:55, Martin Kepplinger wrote:
> 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@xxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Christoph Muellner <christoph.muellner@xxxxxxxxxxxxxxxxxxxxx>
Hi Martin,

Sorry for my lack of reply on this. Stupid week of insane hours at work.
Just about awake again now. Anyhow, only major in here is the change
to what goes in indio_dev->name which should be the part name, not the
driver one.

Otherwise, few minor bits and bobs inline that you can pretty much ignore
if you like.

Jonathan
> ---
> 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;
> +};
> +
This is big an uggly enough that I'd be tempted to add some formal
(e.g. kerneldoc) documentation to the structure. Not vital, but
nice to have!
> +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;
Could tidy this up a bit whilst here if you like (I don't mind if you do
or not ;)
return !!(ret & BIT(chan->scan_index + chip->ev_cfg_chan_shift)) is
my personal slight preferene.

> }
>
> 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
> + */
No particularly problem with this comment, other than 'Why is it here?'
I'd move it down to just above the actual structure element below, then
it is obvious what it is talking about.
> +
> +static const struct mma_chip_info mma_chip_info_table[] = {
> + [mma8452] = {
> + .chip_id = MMA8452_DEVICE_ID,
Not used in this patch. Introduce it when it is :)

> + .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;
The name provided here should be the part name (as per id->name)
not the 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,
> },
>

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