Re: [PATCH v2] iio: light: Add support for ROHM RPR0521 sensor

Peter Meerwald
2015-05-28T13:34:53Z

> >> +static const struct rpr0521_gain_info {
> >> + u8 reg;
> >> + u8 mask;
> >> + u8 shift;
> >> + int *gain;
> >
> > why not const int *?
>
> Correct. Will fix.
>
> >
> >> + int size;
> >> +} rpr0521_gain[] = {
> >> + [RPR0521_CHAN_ALS_DATA0] = {
> >> + .reg = RPR0521_REG_ALS_CTRL,
> >> + .mask = RPR0521_ALS_DATA0_GAIN_MASK,
> >> + .shift = RPR0521_ALS_DATA0_GAIN_SHIFT,
> >> + .gain = (int *)rpr0521_als_gain,

const int* would take care of the cast here as well

> >> + .size = ARRAY_SIZE(rpr0521_als_gain),
> >> + },
> >> + [RPR0521_CHAN_ALS_DATA1] = {
> >> + .reg = RPR0521_REG_ALS_CTRL,
> >> + .mask = RPR0521_ALS_DATA1_GAIN_MASK,
> >> + .shift = RPR0521_ALS_DATA1_GAIN_SHIFT,
> >> + .gain = (int *)rpr0521_als_gain,
> >> + .size = ARRAY_SIZE(rpr0521_als_gain),
> >> + },
> >> + [RPR0521_CHAN_PXS] = {
> >> + .reg = RPR0521_REG_PXS_CTRL,
> >> + .mask = RPR0521_PXS_GAIN_MASK,
> >> + .shift = RPR0521_PXS_GAIN_SHIFT,
> >> + .gain = (int *)rpr0521_pxs_gain,
> >> + .size = ARRAY_SIZE(rpr0521_pxs_gain),
> >> + },
> >> +};
> >> +
> >> +struct rpr0521_data {
> >> + struct i2c_client *client;
> >> +
> >> + /* protect device params updates (e.g state, gain) */
> >> + struct mutex lock;
> >> +
> >> + /* device active status */
> >> + bool als_dev_en;
> >> + bool pxs_dev_en;
> >> +
> >> + /* optimize runtime pm ops - enable device only if needed */
> >> + bool als_ps_need_en;
> >> + bool pxs_ps_need_en;
> >> +
> >> + struct regmap *regmap;
> >> +};
> >> +
> >> +static const struct iio_chan_spec rpr0521_channels[] = {
> >> + {
> >> + .type = IIO_INTENSITY,
> >> + .modified = 1,
> >> + .address = RPR0521_CHAN_ALS_DATA0,
> >> + .channel2 = IIO_MOD_LIGHT_BOTH,
> >> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> >> + BIT(IIO_CHAN_INFO_CALIBSCALE),
> >
> > why CALIBSCALE and not SCALE?
>
> Because this is used to set/get gain, which is used by the hardware
> to do proper scaling.
>
> AFAIK this should be calibscale.

in sysfs-bus-iiof on CALIBSCALE: Hardware applied calibration scale factor
(assumed to fix production inaccuracies).

this doesn't seem applicable here, it is a gain factor controlling
measurement resolution

> >
> >> + },
> >> + {
> >> + .type = IIO_INTENSITY,
> >> + .modified = 1,
> >> + .address = RPR0521_CHAN_ALS_DATA1,
> >> + .channel2 = IIO_MOD_LIGHT_IR,
> >> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> >> + BIT(IIO_CHAN_INFO_CALIBSCALE),
> >> + },
> >> + {
> >> + .type = IIO_PROXIMITY,
> >> + .address = RPR0521_CHAN_PXS,
> >> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> >> + BIT(IIO_CHAN_INFO_CALIBSCALE),
> >> + }
> >> +};
> >> +
> >> +static int rpr0521_als_enable(struct rpr0521_data *data, u8 status)
> >> +{
> >> + int ret;
> >> +
> >> + ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
> >> + RPR0521_MODE_ALS_MASK,
> >> + status);
> >> + if (ret < 0)
> >> + return ret;
> >> +
> >> + data->als_dev_en = true;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int rpr0521_pxs_enable(struct rpr0521_data *data, u8 status)
> >> +{
> >> + int ret;
> >> +
> >> + ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
> >> + RPR0521_MODE_PXS_MASK,
> >> + status);
> >
> > status would fit on the line above?
>
> Yes it looks so :). The same for als_enable.
>
> >
> >> + if (ret < 0)
> >> + return ret;
> >> +
> >> + data->pxs_dev_en = true;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +/**
> >> + * rpr0521_set_power_state - handles runtime PM state and sensors enabled status
> >> + *
> >> + * @data: rpr0521 device private data
> >> + * @on: state to be set for devices in @device_mask
> >> + * @device_mask: bitmask specifying for which device we need to update @on state
> >> + *
> >> + * We rely on rpr0521_runtime_resume to enable our @device_mask devices, but
> >> + * if (for example) PXS was enabled (pxs_dev_en = true) by a previous call to
> >> + * rpr0521_runtime_resume and we want to enable ALS we MUST set ALS enable
> >> + * bit of RPR0521_REG_MODE_CTRL here because rpr0521_runtime_resume will not
> >> + * be called twice.
> >> + */
> >> +static int rpr0521_set_power_state(struct rpr0521_data *data, bool on,
> >> + u8 device_mask)
> >> +{
> >> +#ifdef CONFIG_PM
> >> + int ret;
> >> + u8 update_mask = 0;
> >> +
> >> + if (device_mask & RPR0521_MODE_ALS_MASK) {
> >> + if (on && !data->als_ps_need_en && data->pxs_dev_en)
> >> + update_mask |= RPR0521_MODE_ALS_MASK;
> >> + else
> >> + data->als_ps_need_en = on;
> >> + }
> >> +
> >> + if (device_mask & RPR0521_MODE_PXS_MASK) {
> >> + if (on && !data->pxs_ps_need_en && data->als_dev_en)
> >> + update_mask |= RPR0521_MODE_PXS_MASK;
> >> + else
> >> + data->pxs_ps_need_en = on;
> >> + }
> >> +
> >> + if (update_mask) {
> >> + ret = regmap_update_bits(data->regmap, RPR0521_REG_MODE_CTRL,
> >> + update_mask, update_mask);
> >> + if (ret < 0)
> >> + return ret;
> >> + }
> >> +
> >> + if (on) {
> >> + ret = pm_runtime_get_sync(&data->client->dev);
> >> + } else {
> >> + pm_runtime_mark_last_busy(&data->client->dev);
> >> + ret = pm_runtime_put_autosuspend(&data->client->dev);
> >> + }
> >> + if (ret < 0) {
> >> + dev_err(&data->client->dev,
> >> + "Failed: rpr0521_set_power_state for %d, ret %d\n",
> >> + on, ret);
> >> + if (on)
> >> + pm_runtime_put_noidle(&data->client->dev);
> >> +
> >> + return ret;
> >> + }
> >> +#endif
> >> + return 0;
> >> +}
> >> +
> >> +static int rpr0521_get_gain_index(int *gainv, int size, int gain)
> >> +{
> >> + int i;
> >> +
> >> + for (i = 0; i < size; i++)
> >> + if (gain == gainv[i])
> >> + return i;
> >> +
> >> + return -EINVAL;
> >> +}
> >> +
> >> +static int rpr0521_get_gain(struct rpr0521_data *data, int chan, int *val)
> >> +{
> >> + int ret, reg, idx;
> >> +
> >> + ret = regmap_read(data->regmap, rpr0521_gain[chan].reg, &reg);
> >> + if (ret < 0)
> >> + return ret;
> >> +
> >> + idx = (rpr0521_gain[chan].mask & reg) >> rpr0521_gain[chan].shift;
> >> + *val = rpr0521_gain[chan].gain[idx];
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int rpr0521_set_gain(struct rpr0521_data *data, int chan, int val)
> >> +{
> >> + int idx;
> >> +
> >> + idx = rpr0521_get_gain_index(rpr0521_gain[chan].gain,
> >> + rpr0521_gain[chan].size, val);
> >> + if (idx < 0)
> >> + return idx;
> >> +
> >> + return regmap_update_bits(data->regmap, rpr0521_gain[chan].reg,
> >> + rpr0521_gain[chan].mask,
> >> + idx << rpr0521_gain[chan].shift);
> >> +}
> >> +
> >> +static int rpr0521_read_raw(struct iio_dev *indio_dev,
> >> + struct iio_chan_spec const *chan, int *val,
> >> + int *val2, long mask)
> >> +{
> >> + struct rpr0521_data *data = iio_priv(indio_dev);
> >> + int ret;
> >> + u8 device_mask;
> >> + __le16 raw_data;
> >> +
> >> + switch (mask) {
> >> + case IIO_CHAN_INFO_RAW:
> >> + switch (chan->type) {
> >
> > could put the mask into _data_reg to avoid the switch
> Looks good. Then, here we'll only check for a valid chan->type?
>
> if (chan->type != IIO_INTENSITY && chan->type != IIO_PROXIMITY)
> return -EINVAL.
>
> Or we can consider that the chan->type is always valid?

I'd think so; you also assume that chan->address is valid

I suggest to use chan->address to point to a table containing the
address and the mask

>
> >
> >> + case IIO_INTENSITY:
> >> + device_mask = RPR0521_MODE_ALS_MASK;
> >> + break;
> >> + case IIO_PROXIMITY:
> >> + device_mask = RPR0521_MODE_PXS_MASK;
> >> + break;
> >> + default:
> >> + return -EINVAL;
> >> + }
> >> + mutex_lock(&data->lock);
> >> + ret = rpr0521_set_power_state(data, true, device_mask);
> >> + if (ret < 0) {
> >> + mutex_unlock(&data->lock);
> >> + return ret;
> >> + }
> >> +
> >> + ret = regmap_bulk_read(data->regmap,
> >> + rpr0521_data_reg[chan->address],
> >> + &raw_data, 2);
> >> + if (ret < 0) {
> >> + rpr0521_set_power_state(data, false, device_mask);
> >> + mutex_unlock(&data->lock);
> >> + return ret;
> >> + }
> >> +
> >> + ret = rpr0521_set_power_state(data, false, device_mask);
> >> + mutex_unlock(&data->lock);
> >> + if (ret < 0)
> >> + return ret;
> >> +
> >> + *val = le16_to_cpu(raw_data);
> >> + /*
> >> + * proximity uses 12 bits, with bits 7:4 of PXS MSB DATA
> >> + * being always zero. Also, proximity MUST be exposed as
> >> + * a distance with lower values for closer objects.
> >
> > this matter hasn't been settled, all other proximity sensor drivers do it
> > the other way around
>
> Which sensors? It means they do not agree with the ABI:
>
> http://lxr.free-electrons.com/source/Documentation/ABI/testing/sysfs-bus-iio#L1131

that 'clarification' was added recently,
614e8842ddf5502f0e781f91695bfbc1e1e1d9b6 (with 3.18)
"Proximity measurement .. by observing reflectivity"

high proximity <-> high reflectivity -- this is the reality of what most
sensors output (including yours)

proximity and distance are opposite concepts;
high proximity <-> low distance, and vice versa

the distance part doesn't make sense in the ABI description

> >
> >> + */
> >> + if (chan->type == IIO_PROXIMITY)
> >> + *val = RPR0521_PXS_MAX_VAL - *val;
> >
> > really this should be _PROCESSED, not _RAW?
>
> I understand and it makes sense. Anyhow, looking at
> drivers/iio/proximity/sx9500.c
> it seems to be using _RAW.
>
> > how to handle it for buffered reads?
>
> Not sure I understand this. Care to add more details :)?

> I would expect that for buffer mode we create an item with 12 realbits and
> 16 storage bits, and to copy the data from register to buffer.

in buffered mode we want to avoid manipulating the data (i.e. MAX_DATA -
measurement_value)

since MAX_DATA is not exposed, user mode cannot do this computation and
_RAW differs from the buffered output

(I assume that we want to have buffered output correspond to _RAW values)

> >> + pm_runtime_set_autosuspend_delay(&client->dev, RPR0521_SLEEP_DELAY_MS);
> >> + pm_runtime_use_autosuspend(&client->dev);
> >> +
> >> + return 0;
> >
> > maybe some whitespace here
> >
> do you mean remove the new line? :)

add a newline if I predict Jonathan's perference correctly :)

--

Peter Meerwald
+43-664-2444418 (mobile)