| Message ID | d51d5e2b3eff65fd86aeb47840db9cd413d96668.1682340947.git.mazziesaccount@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Support ROHM BU27008 RGB sensor | expand |
On Mon, Apr 24, 2023 at 04:10:09PM +0300, Matti Vaittinen wrote: > The ROHM BU27008 is a sensor with 5 photodiodes (red, green, blue, clear > and IR) with four configurable channels. Red and green being always > available and two out of the rest three (blue, clear, IR) can be > selected to be simultaneously measured. Typical application is adjusting > LCD backlight of TVs, mobile phones and tablet PCs. > > Add initial support for the ROHM BU27008 color sensor. > - raw_read() of RGB and clear channels > - triggered buffer w/ DRDY interrtupt ... This... > +#include <linux/bits.h> ...is guaranteed to be included by this. > +#include <linux/bitops.h> ... > +static const struct of_device_id bu27008_of_match[] = { > + { .compatible = "rohm,bu27008", }, Inner comma is not necessary to have. > + { } > +};
On 4/24/23 18:22, Andy Shevchenko wrote: > On Mon, Apr 24, 2023 at 04:10:09PM +0300, Matti Vaittinen wrote: >> The ROHM BU27008 is a sensor with 5 photodiodes (red, green, blue, clear >> and IR) with four configurable channels. Red and green being always >> available and two out of the rest three (blue, clear, IR) can be >> selected to be simultaneously measured. Typical application is adjusting >> LCD backlight of TVs, mobile phones and tablet PCs. >> >> Add initial support for the ROHM BU27008 color sensor. >> - raw_read() of RGB and clear channels >> - triggered buffer w/ DRDY interrtupt > > ... > > This... > >> +#include <linux/bits.h> > > ...is guaranteed to be included by this. > >> +#include <linux/bitops.h> Out of the curiosity - do we have a rule and rationale for explicitly including headers with 'stuff' we use Vs. trusting some header being included by another one? I've not thought much of this so I don't know if there are any pros/cons? > ... > >> +static const struct of_device_id bu27008_of_match[] = { >> + { .compatible = "rohm,bu27008", }, > > Inner comma is not necessary to have. Thanks. Yours, -- Matti
On Tue, Apr 25, 2023 at 08:24:01AM +0300, Matti Vaittinen wrote: > On 4/24/23 18:22, Andy Shevchenko wrote: > > On Mon, Apr 24, 2023 at 04:10:09PM +0300, Matti Vaittinen wrote: ... > > This... > > > > > +#include <linux/bits.h> > > > > ...is guaranteed to be included by this. > > > > > +#include <linux/bitops.h> > > Out of the curiosity - do we have a rule and rationale for explicitly > including headers with 'stuff' we use Vs. trusting some header being > included by another one? I've not thought much of this so I don't know if > there are any pros/cons? That's what we are starving for actually. Currently this is a tribe knowledge which one gets while being involved into Linux kernel development for a long time and being capable of keeping an eye on tree wide, library or similar changes. I would love to see some (preferably generated) list of the header dependencies. Yet, the header dependency hell should be solved meanwhile (see Ingo's 2k+ patch series).
Hi Matti, [...] > +static int bu27008_get_int_time(struct bu27008_data *data) this is providing the time in 'us' if I understood correctly. Can you add it at the end of the function to make it clear? bu27008_get_int_time_us(). No need to resend it just for this. > +{ > + int ret, sel; > + > + ret = bu27008_get_int_time_sel(data, &sel); > + if (ret) > + return ret; > + > + return iio_gts_find_int_time_by_sel(&data->gts, > + sel & BU27008_MASK_MEAS_MODE); > +} [...] > +static int bu27008_try_set_int_time(struct bu27008_data *data, int int_time_new) > +{ > + int ret, old_time_sel, new_time_sel, old_gain, new_gain; > + > + mutex_lock(&data->mutex); > + > + ret = bu27008_get_int_time_sel(data, &old_time_sel); > + if (ret < 0) > + goto unlock_out; > + > + if (!iio_gts_valid_time(&data->gts, int_time_new)) { > + dev_dbg(data->dev, "Unsupported integration time %u\n", > + int_time_new); > + > + ret = -EINVAL; > + goto unlock_out; > + } > + new_time_sel = iio_gts_find_sel_by_int_time(&data->gts, int_time_new); > + if (new_time_sel == old_time_sel) { > + ret = 0; ret is already '0' here. > + goto unlock_out; > + } [...] > +static int bu27008_read_one(struct bu27008_data *data, struct iio_dev *idev, > + struct iio_chan_spec const *chan, int *val, int *val2) > +{ > + int ret, int_time; > + > + ret = bu27008_chan_cfg(data, chan); > + if (ret) > + return ret; > + > + ret = bu27008_meas_set(data, BU27008_MEAS_EN); > + if (ret) > + return ret; > + > + int_time = bu27008_get_int_time(data); > + if (int_time < 0) > + int_time = 400000; > + > + msleep((int_time + 500) / 1000); What is this 500 doing? Is it making a real difference? it's 0.5ms. What's the minimum int_time? Can we set a minimum, as well, just for the sake of the msleep? > + ret = bu27008_chan_read_data(data, chan->address, val); > + if (!ret) > + ret = IIO_VAL_INT; [...] > +static int bu27008_set_scale(struct bu27008_data *data, > + struct iio_chan_spec const *chan, > + int val, int val2) > +{ > + int ret, gain_sel, time_sel, i; > + > + if (chan->scan_index == BU27008_IR) > + return -EINVAL; > + > + mutex_lock(&data->mutex); > + > + ret = bu27008_get_int_time_sel(data, &time_sel); > + if (ret < 0) > + goto unlock_out; > + > + extra line here. > + ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts, time_sel, > + val, val2 * 1000, &gain_sel); > + if (ret) { > + /* Could not support new scale with existing int-time */ > + int new_time_sel; > + > + for (i = 0; i < data->gts.num_itime; i++) { > + new_time_sel = data->gts.itime_table[i].sel; > + ret = iio_gts_find_gain_sel_for_scale_using_time( > + &data->gts, new_time_sel, val, val2 * 1000, > + &gain_sel); > + if (!ret) > + break; > + } > + if (i == data->gts.num_itime) { > + dev_err(data->dev, "Can't support scale %u %u\n", val, > + val2); > + > + ret = -EINVAL; > + goto unlock_out; > + } > + > + ret = bu27008_set_int_time_sel(data, new_time_sel); > + if (ret) > + goto unlock_out; > + } just a nit: I see you got tight here and goto's are not made only for error handling. You could: if (!ret) goto something; /* * everything that you have inside the 'if (ret)' with * one level of indentation less */ something: ret = bu27008_write_gain_sel(data, gain_sel); /* ... */ free to ignore this comment, though, I just saw that there are a few cases where you can save some indentation above. > + > + ret = bu27008_write_gain_sel(data, gain_sel); > + > +unlock_out: > + mutex_unlock(&data->mutex); > + > + return ret; > +} [...] > +static int bu27008_chip_init(struct bu27008_data *data) > +{ > + int ret; > + > + ret = regmap_update_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL, > + BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET); > + if (ret) > + return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); > + > + /* > + * The data-sheet does not tell how long performing the IC reset takes. > + * However, the data-sheet says the minimum time it takes the IC to be > + * able to take inputs after power is applied, is 100 uS. I'd assume > + * > 1 mS is enough. > + */ > + msleep(1); please use usleep_range(). > + > + return ret; > +} [...] > +static irqreturn_t bu27008_trigger_handler(int irq, void *p) Do we really need to be in atomic context here? Can this be handled from a thread? > +{ > + struct iio_poll_func *pf = p; > + struct iio_dev *idev = pf->indio_dev; > + struct bu27008_data *data = iio_priv(idev); > + struct { > + __le16 chan[BU27008_NUM_HW_CHANS]; > + s64 ts __aligned(8); > + } raw; > + int ret, dummy; > + > + memset(&raw, 0, sizeof(raw)); > + > + /* > + * After some measurements, it seems reading the > + * BU27008_REG_MODE_CONTROL3 debounces the IRQ line > + */ > + ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL3, &dummy); > + if (ret < 0) > + goto err_read; > + > + ret = regmap_bulk_read(data->regmap, BU27008_REG_DATA0_LO, &raw.chan, > + sizeof(raw.chan)); > + if (ret < 0) > + goto err_read; > + > + iio_push_to_buffers_with_timestamp(idev, &raw, pf->timestamp); > +err_read: > + iio_trigger_notify_done(idev->trig); > + > + return IRQ_HANDLED; > +} [...] > +static int bu27008_probe(struct i2c_client *i2c) > +{ > + struct device *dev = &i2c->dev; > + struct iio_trigger *itrig; > + struct bu27008_data *data; > + struct regmap *regmap; > + unsigned int part_id, reg; > + struct iio_dev *idev; > + char *name; > + int ret; > + > + if (!i2c->irq) > + dev_warn(dev, "No IRQ configured\n"); [...] > + if (i2c->irq) { e.g.: if (!i2c->irq) { dev_warn(dev, "No IRQ configured\n"); goto no_irq; } /* ... */ or, if you don't like the goto used like this... > + ret = devm_iio_triggered_buffer_setup(dev, idev, > + &iio_pollfunc_store_time, > + bu27008_trigger_handler, > + &bu27008_buffer_ops); > + if (ret) > + return dev_err_probe(dev, ret, > + "iio_triggered_buffer_setup_ext FAIL\n"); > + > + itrig = devm_iio_trigger_alloc(dev, "%sdata-rdy-dev%d", > + idev->name, iio_device_id(idev)); > + if (!itrig) > + return -ENOMEM; > + > + data->trig = itrig; > + > + itrig->ops = &bu27008_trigger_ops; > + iio_trigger_set_drvdata(itrig, data); > + > + name = devm_kasprintf(dev, GFP_KERNEL, "%s-bu27008", > + dev_name(dev)); > + > + ret = devm_request_threaded_irq(dev, i2c->irq, > + iio_pollfunc_store_time, > + &bu27008_irq_thread_handler, > + IRQF_ONESHOT, name, idev->pollfunc); > + if (ret) > + return dev_err_probe(dev, ret, > + "Could not request IRQ\n"); > + > + > + ret = devm_iio_trigger_register(dev, itrig); > + if (ret) > + return dev_err_probe(dev, ret, > + "Trigger registration failed\n"); > + } } else { dev_warn(dev, "No IRQ configured\n"); } and save the first 'if' of this function. > + > + ret = devm_iio_device_register(dev, idev); > + if (ret) > + return dev_err_probe(dev, ret, > + "Unable to register iio device\n"); > + > + return ret; > +} [...] Andi
Hi Andi, Thanks for the review! It's nice to see you're still keeping an eye on ROHM / Kionix senor drivers ;) On 4/25/23 19:45, Andi Shyti wrote: > Hi Matti, > > [...] > >> +static int bu27008_get_int_time(struct bu27008_data *data) > > this is providing the time in 'us' if I understood correctly. > > Can you add it at the end of the function to make it clear? > bu27008_get_int_time_us(). > > No need to resend it just for this. I like the idea. > >> +{ >> + int ret, sel; >> + >> + ret = bu27008_get_int_time_sel(data, &sel); >> + if (ret) >> + return ret; >> + >> + return iio_gts_find_int_time_by_sel(&data->gts, >> + sel & BU27008_MASK_MEAS_MODE); >> +} > > [...] > >> +static int bu27008_try_set_int_time(struct bu27008_data *data, int int_time_new) >> +{ >> + int ret, old_time_sel, new_time_sel, old_gain, new_gain; >> + >> + mutex_lock(&data->mutex); >> + >> + ret = bu27008_get_int_time_sel(data, &old_time_sel); >> + if (ret < 0) >> + goto unlock_out; >> + >> + if (!iio_gts_valid_time(&data->gts, int_time_new)) { >> + dev_dbg(data->dev, "Unsupported integration time %u\n", >> + int_time_new); >> + >> + ret = -EINVAL; >> + goto unlock_out; >> + } >> + new_time_sel = iio_gts_find_sel_by_int_time(&data->gts, int_time_new); >> + if (new_time_sel == old_time_sel) { >> + ret = 0; > > ret is already '0' here. Good point! Kills the ugly brackets just nice :) > >> + goto unlock_out; >> + } > > [...] > >> +static int bu27008_read_one(struct bu27008_data *data, struct iio_dev *idev, >> + struct iio_chan_spec const *chan, int *val, int *val2) >> +{ >> + int ret, int_time; >> + >> + ret = bu27008_chan_cfg(data, chan); >> + if (ret) >> + return ret; >> + >> + ret = bu27008_meas_set(data, BU27008_MEAS_EN); >> + if (ret) >> + return ret; >> + >> + int_time = bu27008_get_int_time(data); >> + if (int_time < 0) >> + int_time = 400000; >> + >> + msleep((int_time + 500) / 1000); > > What is this 500 doing? Is it making a real difference? it's > 0.5ms. Thanks for the question, having extra pairs of eyes helps spotting brainfarts :) The 500 here is half of the value of the divider - idea was to do rounding correctly upwards to prevent premature wake-up. Well, this is incorrect because we should always round up the sleep time, not just 'mathematically correctly' (Eg, not only upwards when value >= 0.5 but upwards always when the division is not even). After this being said, integration times for this device are full milli seconds so they can all be divided by 1000 uS. Nevertheless, it's good to note that the sensor is definitely not being clocked by the same clock as CPU and I assume the timing for it will be drifting quite a bit from the CPU clock. This means some sensors will for sure complete the measurement later than this wake-up. In order to tackle this we have the valid-bit polling in bu27008_chan_read_data(). So, at the end of the day, this rounding correction is lkely to be just some unnecessary noise. > What's the minimum int_time? Can we set a minimum, as well, just > for the sake of the msleep? Can you please elaborate what you mean by this? The minimum integration time for bu27008 is 55 mS and this is set in the time tables for the gts-helpers. The bu27008_get_int_time() should never return valid time smaller than that. >> + ret = bu27008_chan_read_data(data, chan->address, val); >> + if (!ret) >> + ret = IIO_VAL_INT; > > [...] > >> +static int bu27008_set_scale(struct bu27008_data *data, >> + struct iio_chan_spec const *chan, >> + int val, int val2) >> +{ >> + int ret, gain_sel, time_sel, i; >> + >> + if (chan->scan_index == BU27008_IR) >> + return -EINVAL; >> + >> + mutex_lock(&data->mutex); >> + >> + ret = bu27008_get_int_time_sel(data, &time_sel); >> + if (ret < 0) >> + goto unlock_out; >> + >> + > > extra line here. > >> + ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts, time_sel, >> + val, val2 * 1000, &gain_sel); >> + if (ret) { >> + /* Could not support new scale with existing int-time */ >> + int new_time_sel; >> + >> + for (i = 0; i < data->gts.num_itime; i++) { >> + new_time_sel = data->gts.itime_table[i].sel; >> + ret = iio_gts_find_gain_sel_for_scale_using_time( >> + &data->gts, new_time_sel, val, val2 * 1000, >> + &gain_sel); >> + if (!ret) >> + break; >> + } >> + if (i == data->gts.num_itime) { >> + dev_err(data->dev, "Can't support scale %u %u\n", val, >> + val2); >> + >> + ret = -EINVAL; >> + goto unlock_out; >> + } >> + >> + ret = bu27008_set_int_time_sel(data, new_time_sel); >> + if (ret) >> + goto unlock_out; >> + } > > just a nit: I see you got tight here and goto's are not made only > for error handling. You could: > > if (!ret) > goto something; > > /* > * everything that you have inside the 'if (ret)' with > * one level of indentation less > */ > > something: > ret = bu27008_write_gain_sel(data, gain_sel); > > /* ... */ > > free to ignore this comment, though, I just saw that there are a > few cases where you can save some indentation above. > Thanks for the suggestion. I am not really sure which way I like better. I think the logic is tiny bit easier to follow when the success case is not handled with goto. OTOH, with a proper descriptive goto label (definitely not 'something' ;) ) this "tiny bit" gets, well, tiny. Yet, the indentation is not _that_ deep here - logic does not (in my opinion) get messy because of nesting but iio_gts_find_gain_sel_for_scale_using_time - is a long function name and the call looks kind of ugly. Thanks for the suggestion - I'll see how this looks like and decide when I open the file next time :) >> + >> + ret = bu27008_write_gain_sel(data, gain_sel); >> + >> +unlock_out: >> + mutex_unlock(&data->mutex); >> + >> + return ret; >> +} > > [...] > >> +static int bu27008_chip_init(struct bu27008_data *data) >> +{ >> + int ret; >> + >> + ret = regmap_update_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL, >> + BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET); >> + if (ret) >> + return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); >> + >> + /* >> + * The data-sheet does not tell how long performing the IC reset takes. >> + * However, the data-sheet says the minimum time it takes the IC to be >> + * able to take inputs after power is applied, is 100 uS. I'd assume >> + * > 1 mS is enough. >> + */ >> + msleep(1); > > please use usleep_range(). I prefer to not require setting up hrtimers as we have no real requirements for the duration of this sleep. I know the msleep() is likely to exceed the 1 mS, potentially a lot if there is things to do - but we don't really care at this point. The main thing is to give the HW time to reset while allowing other things to be scheduled. > >> + >> + return ret; >> +} > > [...] > >> +static irqreturn_t bu27008_trigger_handler(int irq, void *p) > > Do we really need to be in atomic context here? Can this be > handled from a thread? As far as I understand, this is handled from a process context. > >> +{ >> + struct iio_poll_func *pf = p; >> + struct iio_dev *idev = pf->indio_dev; >> + struct bu27008_data *data = iio_priv(idev); >> + struct { >> + __le16 chan[BU27008_NUM_HW_CHANS]; >> + s64 ts __aligned(8); >> + } raw; >> + int ret, dummy; >> + >> + memset(&raw, 0, sizeof(raw)); >> + >> + /* >> + * After some measurements, it seems reading the >> + * BU27008_REG_MODE_CONTROL3 debounces the IRQ line >> + */ >> + ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL3, &dummy); >> + if (ret < 0) >> + goto err_read; >> + >> + ret = regmap_bulk_read(data->regmap, BU27008_REG_DATA0_LO, &raw.chan, >> + sizeof(raw.chan)); >> + if (ret < 0) >> + goto err_read; >> + >> + iio_push_to_buffers_with_timestamp(idev, &raw, pf->timestamp); >> +err_read: >> + iio_trigger_notify_done(idev->trig); >> + >> + return IRQ_HANDLED; >> +} > > [...] > >> +static int bu27008_probe(struct i2c_client *i2c) >> +{ >> + struct device *dev = &i2c->dev; >> + struct iio_trigger *itrig; >> + struct bu27008_data *data; >> + struct regmap *regmap; >> + unsigned int part_id, reg; >> + struct iio_dev *idev; >> + char *name; >> + int ret; >> + >> + if (!i2c->irq) >> + dev_warn(dev, "No IRQ configured\n"); > > [...] > >> + if (i2c->irq) { > > e.g.: > > > if (!i2c->irq) { > dev_warn(dev, "No IRQ configured\n"); > goto no_irq; > } > > /* ... */ > > or, if you don't like the goto used like this... > >> + ret = devm_iio_triggered_buffer_setup(dev, idev, >> + &iio_pollfunc_store_time, >> + bu27008_trigger_handler, >> + &bu27008_buffer_ops); >> + if (ret) >> + return dev_err_probe(dev, ret, >> + "iio_triggered_buffer_setup_ext FAIL\n"); >> + >> + itrig = devm_iio_trigger_alloc(dev, "%sdata-rdy-dev%d", >> + idev->name, iio_device_id(idev)); >> + if (!itrig) >> + return -ENOMEM; >> + >> + data->trig = itrig; >> + >> + itrig->ops = &bu27008_trigger_ops; >> + iio_trigger_set_drvdata(itrig, data); >> + >> + name = devm_kasprintf(dev, GFP_KERNEL, "%s-bu27008", >> + dev_name(dev)); >> + >> + ret = devm_request_threaded_irq(dev, i2c->irq, >> + iio_pollfunc_store_time, >> + &bu27008_irq_thread_handler, >> + IRQF_ONESHOT, name, idev->pollfunc); >> + if (ret) >> + return dev_err_probe(dev, ret, >> + "Could not request IRQ\n"); >> + >> + >> + ret = devm_iio_trigger_register(dev, itrig); >> + if (ret) >> + return dev_err_probe(dev, ret, >> + "Trigger registration failed\n"); >> + } > > } else { > dev_warn(dev, "No IRQ configured\n"); > } > > and save the first 'if' of this function. Thanks. I like this suggestion. I should've done it like this in the first place. > >> + >> + ret = devm_iio_device_register(dev, idev); >> + if (ret) >> + return dev_err_probe(dev, ret, >> + "Unable to register iio device\n"); >> + >> + return ret; >> +} Yours, -- Matti
Hi Matti, > Thanks for the review! It's nice to see you're still keeping an eye on ROHM > / Kionix senor drivers ;) yeah... this is fun... if I just had a bit more time :) > > > +static int bu27008_read_one(struct bu27008_data *data, struct iio_dev *idev, > > > + struct iio_chan_spec const *chan, int *val, int *val2) > > > +{ > > > + int ret, int_time; > > > + > > > + ret = bu27008_chan_cfg(data, chan); > > > + if (ret) > > > + return ret; > > > + > > > + ret = bu27008_meas_set(data, BU27008_MEAS_EN); > > > + if (ret) > > > + return ret; > > > + > > > + int_time = bu27008_get_int_time(data); > > > + if (int_time < 0) > > > + int_time = 400000; > > > + > > > + msleep((int_time + 500) / 1000); > > > > What is this 500 doing? Is it making a real difference? it's > > 0.5ms. > > Thanks for the question, having extra pairs of eyes helps spotting > brainfarts :) > > The 500 here is half of the value of the divider - idea was to do rounding > correctly upwards to prevent premature wake-up. Well, this is incorrect > because we should always round up the sleep time, not just 'mathematically > correctly' (Eg, not only upwards when value >= 0.5 but upwards always when > the division is not even). > > After this being said, integration times for this device are full milli > seconds so they can all be divided by 1000 uS. > > Nevertheless, it's good to note that the sensor is definitely not being > clocked by the same clock as CPU and I assume the timing for it will be > drifting quite a bit from the CPU clock. This means some sensors will for > sure complete the measurement later than this wake-up. In order to tackle > this we have the valid-bit polling in bu27008_chan_read_data(). So, at the > end of the day, this rounding correction is lkely to be just some > unnecessary noise. I understand the logic of the waiting, but msleep is not the right function as waiting with msleep is always very approximate, that's why it's recommended to use it for a large waiting period, where the error is smaller. If int_time is 1ms, waiting 1.5 or 2 or 1, is the same thing, most probably you will end up waiting more. > > What's the minimum int_time? Can we set a minimum, as well, just > > for the sake of the msleep? > > Can you please elaborate what you mean by this? The minimum integration time > for bu27008 is 55 mS and this is set in the time tables for the gts-helpers. > The bu27008_get_int_time() should never return valid time smaller than that. Witha minimum i mean a minimum value for the msleep to start working decently. E.g. what if int_time is lower than 1ms? Can we have msleep(0)? [...] > > > +static int bu27008_chip_init(struct bu27008_data *data) > > > +{ > > > + int ret; > > > + > > > + ret = regmap_update_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL, > > > + BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET); > > > + if (ret) > > > + return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); > > > + > > > + /* > > > + * The data-sheet does not tell how long performing the IC reset takes. > > > + * However, the data-sheet says the minimum time it takes the IC to be > > > + * able to take inputs after power is applied, is 100 uS. I'd assume > > > + * > 1 mS is enough. > > > + */ > > > + msleep(1); > > > > please use usleep_range(). > > I prefer to not require setting up hrtimers as we have no real requirements > for the duration of this sleep. I know the msleep() is likely to exceed the > 1 mS, potentially a lot if there is things to do - but we don't really care > at this point. The main thing is to give the HW time to reset while allowing > other things to be scheduled. For the reason above, msleep(1) is quite a meaningless instruction. If you need to wait around 1ms, then usleep_range is the function to be used. Refer, also, to the Documentation/timers/timers-howto.rst > > > + > > > + return ret; > > > +} [...] > > > +static irqreturn_t bu27008_trigger_handler(int irq, void *p) > > > > Do we really need to be in atomic context here? Can this be > > handled from a thread? > > As far as I understand, this is handled from a process context. Sorry... I misread it... I thought you used request_irq() for this and request_threaded_irq() for bu27008_irq_thread_handler(). Ignore :) Andi
On 4/26/23 13:12, Andi Shyti wrote: > Hi Matti, > >> Thanks for the review! It's nice to see you're still keeping an eye on ROHM >> / Kionix senor drivers ;) > > yeah... this is fun... if I just had a bit more time :) > >>>> +static int bu27008_read_one(struct bu27008_data *data, struct iio_dev *idev, >>>> + struct iio_chan_spec const *chan, int *val, int *val2) >>>> +{ >>>> + int ret, int_time; >>>> + >>>> + ret = bu27008_chan_cfg(data, chan); >>>> + if (ret) >>>> + return ret; >>>> + >>>> + ret = bu27008_meas_set(data, BU27008_MEAS_EN); >>>> + if (ret) >>>> + return ret; >>>> + >>>> + int_time = bu27008_get_int_time(data); >>>> + if (int_time < 0) >>>> + int_time = 400000; >>>> + >>>> + msleep((int_time + 500) / 1000); >>> >>> What is this 500 doing? Is it making a real difference? it's >>> 0.5ms. >> >> Thanks for the question, having extra pairs of eyes helps spotting >> brainfarts :) >> >> The 500 here is half of the value of the divider - idea was to do rounding >> correctly upwards to prevent premature wake-up. Well, this is incorrect >> because we should always round up the sleep time, not just 'mathematically >> correctly' (Eg, not only upwards when value >= 0.5 but upwards always when >> the division is not even). >> >> After this being said, integration times for this device are full milli >> seconds so they can all be divided by 1000 uS. >> >> Nevertheless, it's good to note that the sensor is definitely not being >> clocked by the same clock as CPU and I assume the timing for it will be >> drifting quite a bit from the CPU clock. This means some sensors will for >> sure complete the measurement later than this wake-up. In order to tackle >> this we have the valid-bit polling in bu27008_chan_read_data(). So, at the >> end of the day, this rounding correction is lkely to be just some >> unnecessary noise. > > I understand the logic of the waiting, but msleep is not the > right function as waiting with msleep is always very approximate, > that's why it's recommended to use it for a large waiting period, > where the error is smaller. > > If int_time is 1ms, waiting 1.5 or 2 or 1, is the same thing, > most probably you will end up waiting more. Well, the light sensors are slow. The shortest time with BU27008 is 55 mS, longest being 400 mS. I think msleep fits Ok for this purpose. >>> What's the minimum int_time? Can we set a minimum, as well, just >>> for the sake of the msleep? >> >> Can you please elaborate what you mean by this? The minimum integration time >> for bu27008 is 55 mS and this is set in the time tables for the gts-helpers. >> The bu27008_get_int_time() should never return valid time smaller than that. > > Witha minimum i mean a minimum value for the msleep to start > working decently. E.g. what if int_time is lower than 1ms? Can we > have msleep(0)? As mentioned, int_time for bu27008 will be in a range of 55 ... 400 mS. > > [...] > >>>> +static int bu27008_chip_init(struct bu27008_data *data) >>>> +{ >>>> + int ret; >>>> + >>>> + ret = regmap_update_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL, >>>> + BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET); >>>> + if (ret) >>>> + return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); >>>> + >>>> + /* >>>> + * The data-sheet does not tell how long performing the IC reset takes. >>>> + * However, the data-sheet says the minimum time it takes the IC to be >>>> + * able to take inputs after power is applied, is 100 uS. I'd assume >>>> + * > 1 mS is enough. >>>> + */ >>>> + msleep(1); >>> >>> please use usleep_range(). >> >> I prefer to not require setting up hrtimers as we have no real requirements >> for the duration of this sleep. I know the msleep() is likely to exceed the >> 1 mS, potentially a lot if there is things to do - but we don't really care >> at this point. The main thing is to give the HW time to reset while allowing >> other things to be scheduled. > > For the reason above, msleep(1) is quite a meaningless > instruction. If you need to wait around 1ms, then usleep_range is > the function to be used. > > Refer, also, to the Documentation/timers/timers-howto.rst I know the msleep() may sleep much longer. It still is not meaningless. Here we use the msleep() in a purpose: "Sleep at least 1 mS, but actually I don't care if that is 20 mS or more - as long as you allow scheduling other things with as little overhead as possible". For that purpose msleep() works just perfectly :) I actually had a comment clarifying this in previous IIO driver I wrote (just to avoid confusing reviewers) but Jonathan asked me to remove the comment ;) Yours, -- Matti
Hi Matti, > > > > > +static int bu27008_chip_init(struct bu27008_data *data) > > > > > +{ > > > > > + int ret; > > > > > + > > > > > + ret = regmap_update_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL, > > > > > + BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET); > > > > > + if (ret) > > > > > + return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); > > > > > + > > > > > + /* > > > > > + * The data-sheet does not tell how long performing the IC reset takes. > > > > > + * However, the data-sheet says the minimum time it takes the IC to be > > > > > + * able to take inputs after power is applied, is 100 uS. I'd assume > > > > > + * > 1 mS is enough. > > > > > + */ > > > > > + msleep(1); > > > > > > > > please use usleep_range(). > > > > > > I prefer to not require setting up hrtimers as we have no real requirements > > > for the duration of this sleep. I know the msleep() is likely to exceed the > > > 1 mS, potentially a lot if there is things to do - but we don't really care > > > at this point. The main thing is to give the HW time to reset while allowing > > > other things to be scheduled. > > > > For the reason above, msleep(1) is quite a meaningless > > instruction. If you need to wait around 1ms, then usleep_range is > > the function to be used. > > > > Refer, also, to the Documentation/timers/timers-howto.rst > > I know the msleep() may sleep much longer. It still is not meaningless. Here > we use the msleep() in a purpose: > > "Sleep at least 1 mS, but actually I don't care if that is 20 mS or more - > as long as you allow scheduling other things with as little overhead as > possible". > > For that purpose msleep() works just perfectly :) > > I actually had a comment clarifying this in previous IIO driver I wrote > (just to avoid confusing reviewers) but Jonathan asked me to remove the > comment ;) OK... ok... you convinced me :) Thanks, will check soon your v3. Andi
diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig index 6fa31fcd71a1..7888fc439b2f 100644 --- a/drivers/iio/light/Kconfig +++ b/drivers/iio/light/Kconfig @@ -289,6 +289,20 @@ config JSA1212 To compile this driver as a module, choose M here: the module will be called jsa1212. +config ROHM_BU27008 + tristate "ROHM BU27008 color (RGB+C/IR) sensor" + depends on I2C + select REGMAP_I2C + select IIO_GTS_HELPER + help + Enable support for the ROHM BU27008 color sensor. + The ROHM BU27008 is a sensor with 5 photodiodes (red, green, + blue, clear and IR) with four configurable channels. Red and + green being always available and two out of the rest three + (blue, clear, IR) can be selected to be simultaneously measured. + Typical application is adjusting LCD backlight of TVs, + mobile phones and tablet PCs. + config ROHM_BU27034 tristate "ROHM BU27034 ambient light sensor" depends on I2C diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile index 985f6feaccd4..881173952301 100644 --- a/drivers/iio/light/Makefile +++ b/drivers/iio/light/Makefile @@ -39,6 +39,7 @@ obj-$(CONFIG_NOA1305) += noa1305.o obj-$(CONFIG_OPT3001) += opt3001.o obj-$(CONFIG_PA12203001) += pa12203001.o obj-$(CONFIG_ROHM_BU27034) += rohm-bu27034.o +obj-$(CONFIG_ROHM_BU27008) += rohm-bu27008.o obj-$(CONFIG_RPR0521) += rpr0521.o obj-$(CONFIG_SI1133) += si1133.o obj-$(CONFIG_SI1145) += si1145.o diff --git a/drivers/iio/light/rohm-bu27008.c b/drivers/iio/light/rohm-bu27008.c new file mode 100644 index 000000000000..d39fc4d1f43b --- /dev/null +++ b/drivers/iio/light/rohm-bu27008.c @@ -0,0 +1,964 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * BU27008 ROHM Colour Sensor + * + * Copyright (c) 2023, ROHM Semiconductor. + */ + +#include <linux/bits.h> +#include <linux/bitfield.h> +#include <linux/bitops.h> +#include <linux/device.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/property.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/units.h> + +#include <linux/iio/iio.h> +#include <linux/iio/iio-gts-helper.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +#define BU27008_REG_SYSTEM_CONTROL 0x40 +#define BU27008_MASK_SW_RESET BIT(7) +#define BU27008_MASK_PART_ID GENMASK(5, 0) +#define BU27008_ID 0x1a +#define BU27008_REG_MODE_CONTROL1 0x41 +#define BU27008_MASK_MEAS_MODE GENMASK(2, 0) +#define BU27008_MASK_CHAN_SEL GENMASK(3, 2) + +#define BU27008_REG_MODE_CONTROL2 0x42 +#define BU27008_MASK_RGBC_GAIN GENMASK(7, 3) +#define BU27008_MASK_IR_GAIN_LO GENMASK(2, 0) +#define BU27008_SHIFT_IR_GAIN 3 + +#define BU27008_REG_MODE_CONTROL3 0x43 +#define BU27008_MASK_VALID BIT(7) +#define BU27008_MASK_INT_EN BIT(1) +#define BU27008_INT_EN BU27008_MASK_INT_EN +#define BU27008_INT_DIS 0 +#define BU27008_MASK_MEAS_EN BIT(0) +#define BU27008_MEAS_EN BIT(0) +#define BU27008_MEAS_DIS 0 + +#define BU27008_REG_DATA0_LO 0x50 +#define BU27008_REG_DATA1_LO 0x52 +#define BU27008_REG_DATA2_LO 0x54 +#define BU27008_REG_DATA3_LO 0x56 +#define BU27008_REG_DATA3_HI 0x57 +#define BU27008_REG_MANUFACTURER_ID 0x92 +#define BU27008_REG_MAX BU27008_REG_MANUFACTURER_ID + +enum { + BU27008_RED, /* Always data0 */ + BU27008_GREEN, /* Always data1 */ + BU27008_BLUE, /* data2, configurable (blue / clear) */ + BU27008_CLEAR, /* data2 or data3 */ + BU27008_IR, /* data3 */ + BU27008_NUM_CHANS +}; + +enum { + BU27008_DATA0, /* Always RED */ + BU27008_DATA1, /* Always GREEN */ + BU27008_DATA2, /* Blue or Clear */ + BU27008_DATA3, /* IR or Clear */ + BU27008_NUM_HW_CHANS +}; + +/* We can always measure red and green at same time */ +#define ALWAYS_SCANNABLE (BIT(BU27008_RED) | BIT(BU27008_GREEN)) + +/* We use these data channel configs. Ensure scan_masks below follow them too */ +#define BU27008_BLUE2_CLEAR3 0x0 /* buffer is R, G, B, C */ +#define BU27008_CLEAR2_IR3 0x1 /* buffer is R, G, C, IR */ +#define BU27008_BLUE2_IR3 0x2 /* buffer is R, G, B, IR */ + +static const unsigned long bu27008_scan_masks[] = { + /* buffer is R, G, B, C */ + ALWAYS_SCANNABLE | BIT(BU27008_BLUE) | BIT(BU27008_CLEAR), + /* buffer is R, G, C, IR */ + ALWAYS_SCANNABLE | BIT(BU27008_CLEAR) | BIT(BU27008_IR), + /* buffer is R, G, B, IR */ + ALWAYS_SCANNABLE | BIT(BU27008_BLUE) | BIT(BU27008_IR), + 0 +}; + +/* + * Available scales with gain 1x - 1024x, timings 55, 100, 200, 400 mS + * Time impacts to gain: 1x, 2x, 4x, 8x. + * + * => Max total gain is HWGAIN * gain by integration time (8 * 1024) = 8192 + * + * Max amplification is (HWGAIN * MAX integration-time multiplier) 1024 * 8 + * = 8192. With NANO scale we get rid of accuracy loss when we start with the + * scale 16.0 for HWGAIN1, INT-TIME 55 mS. This way the nano scale for MAX + * total gain 8192 will be 1953125 + */ +#define BU27008_SCALE_1X 16 + +/* See the data sheet for the "Gain Setting" table */ +#define BU27008_GSEL_1X 0x00 +#define BU27008_GSEL_4X 0x08 +#define BU27008_GSEL_8X 0x09 +#define BU27008_GSEL_16X 0x0a +#define BU27008_GSEL_32X 0x0b +#define BU27008_GSEL_64X 0x0c +#define BU27008_GSEL_256X 0x18 +#define BU27008_GSEL_512X 0x19 +#define BU27008_GSEL_1024X 0x1a + +static const struct iio_gain_sel_pair bu27008_gains[] = { + GAIN_SCALE_GAIN(1, BU27008_GSEL_1X), + GAIN_SCALE_GAIN(4, BU27008_GSEL_4X), + GAIN_SCALE_GAIN(8, BU27008_GSEL_8X), + GAIN_SCALE_GAIN(16, BU27008_GSEL_16X), + GAIN_SCALE_GAIN(32, BU27008_GSEL_32X), + GAIN_SCALE_GAIN(64, BU27008_GSEL_64X), + GAIN_SCALE_GAIN(256, BU27008_GSEL_256X), + GAIN_SCALE_GAIN(512, BU27008_GSEL_512X), + GAIN_SCALE_GAIN(1024, BU27008_GSEL_1024X), +}; + +static const struct iio_gain_sel_pair bu27008_gains_ir[] = { + GAIN_SCALE_GAIN(2, BU27008_GSEL_1X), + GAIN_SCALE_GAIN(4, BU27008_GSEL_4X), + GAIN_SCALE_GAIN(8, BU27008_GSEL_8X), + GAIN_SCALE_GAIN(16, BU27008_GSEL_16X), + GAIN_SCALE_GAIN(32, BU27008_GSEL_32X), + GAIN_SCALE_GAIN(64, BU27008_GSEL_64X), + GAIN_SCALE_GAIN(256, BU27008_GSEL_256X), + GAIN_SCALE_GAIN(512, BU27008_GSEL_512X), + GAIN_SCALE_GAIN(1024, BU27008_GSEL_1024X), +}; + +#define BU27008_MEAS_MODE_100MS 0x00 +#define BU27008_MEAS_MODE_55MS 0x01 +#define BU27008_MEAS_MODE_200MS 0x02 +#define BU27008_MEAS_MODE_400MS 0x04 + +static const struct iio_itime_sel_mul bu27008_itimes[] = { + GAIN_SCALE_ITIME_US(400000, BU27008_MEAS_MODE_400MS, 8), + GAIN_SCALE_ITIME_US(200000, BU27008_MEAS_MODE_200MS, 4), + GAIN_SCALE_ITIME_US(100000, BU27008_MEAS_MODE_100MS, 2), + GAIN_SCALE_ITIME_US(55000, BU27008_MEAS_MODE_55MS, 1), +}; + +/* + * All the RGBC channels share the same gain. + * IR gain can be fine-tuned from the gain set for the RGBC by 2 bit, but this + * would yield quite complex gain setting. Especially since not all bit + * compinations are supported. And in any case setting GAIN for RGBC will + * always also change the IR-gain. + * + * On top of this, the selector '0' which corresponds to hw-gain 1X on RGBC, + * corresponds to gain 2X on IR. Rest of the selctors correspond to same gains + * though. This, however, makes it not possible to use shared gain for all + * RGBC and IR settings even though they are all changed at the one go. + */ +#define BU27008_CHAN(color, data, separate_avail) \ +{ \ + .type = IIO_INTENSITY, \ + .modified = 1, \ + .channel2 = IIO_MOD_LIGHT_##color, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ + BIT(IIO_CHAN_INFO_SCALE), \ + .info_mask_separate_available = (separate_avail), \ + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_INT_TIME), \ + .info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_INT_TIME), \ + .address = BU27008_REG_##data##_LO, \ + .scan_index = BU27008_##color, \ + .scan_type = { \ + .sign = 's', \ + .realbits = 16, \ + .storagebits = 16, \ + .endianness = IIO_LE, \ + }, \ +} + +/* For raw reads we always configure DATA3 for CLEAR */ +static const struct iio_chan_spec bu27008_channels[] = { + BU27008_CHAN(RED, DATA0, BIT(IIO_CHAN_INFO_SCALE)), + BU27008_CHAN(GREEN, DATA1, BIT(IIO_CHAN_INFO_SCALE)), + BU27008_CHAN(BLUE, DATA2, BIT(IIO_CHAN_INFO_SCALE)), + BU27008_CHAN(CLEAR, DATA2, BIT(IIO_CHAN_INFO_SCALE)), + /* + * We don't allow setting scale for IR (because of shared gain bits). + * Hence we don't advertise available ones either. + */ + BU27008_CHAN(IR, DATA3, 0), + IIO_CHAN_SOFT_TIMESTAMP(BU27008_NUM_CHANS), +}; + +struct bu27008_data { + struct regmap *regmap; + struct iio_trigger *trig; + struct device *dev; + struct iio_gts gts; + struct iio_gts gts_ir; + int irq; + + /* + * Prevent changing gain/time config when scale is read/written. + * Similarly, protect the integration_time read/change sequence. + * Prevent changing gain/time when data is read. + */ + struct mutex mutex; +}; + +static const struct regmap_range bu27008_volatile_ranges[] = { + { + .range_min = BU27008_REG_SYSTEM_CONTROL, /* SWRESET */ + .range_max = BU27008_REG_SYSTEM_CONTROL, + }, { + .range_min = BU27008_REG_MODE_CONTROL3, /* VALID */ + .range_max = BU27008_REG_MODE_CONTROL3, + }, { + .range_min = BU27008_REG_DATA0_LO, /* DATA */ + .range_max = BU27008_REG_DATA3_HI, + }, +}; + +static const struct regmap_access_table bu27008_volatile_regs = { + .yes_ranges = &bu27008_volatile_ranges[0], + .n_yes_ranges = ARRAY_SIZE(bu27008_volatile_ranges), +}; + +static const struct regmap_range bu27008_read_only_ranges[] = { + { + .range_min = BU27008_REG_DATA0_LO, + .range_max = BU27008_REG_DATA3_HI, + }, { + .range_min = BU27008_REG_MANUFACTURER_ID, + .range_max = BU27008_REG_MANUFACTURER_ID, + } +}; + +static const struct regmap_access_table bu27008_ro_regs = { + .no_ranges = &bu27008_read_only_ranges[0], + .n_no_ranges = ARRAY_SIZE(bu27008_read_only_ranges), +}; + +static const struct regmap_config bu27008_regmap = { + .reg_bits = 8, + .val_bits = 8, + .max_register = BU27008_REG_MAX, + .cache_type = REGCACHE_RBTREE, + .volatile_table = &bu27008_volatile_regs, + .wr_table = &bu27008_ro_regs, +}; + +#define BU27008_MAX_VALID_RESULT_WAIT_US 50000 +#define BU27008_VALID_RESULT_WAIT_QUANTA_US 1000 + +static int bu27008_chan_read_data(struct bu27008_data *data, int reg, int *val) +{ + int ret, valid; + __le16 tmp; + + ret = regmap_read_poll_timeout(data->regmap, BU27008_REG_MODE_CONTROL3, + valid, (valid & BU27008_MASK_VALID), + BU27008_VALID_RESULT_WAIT_QUANTA_US, + BU27008_MAX_VALID_RESULT_WAIT_US); + if (ret) + return ret; + + ret = regmap_bulk_read(data->regmap, reg, &tmp, sizeof(tmp)); + if (ret) + dev_err(data->dev, "Reading channel data failed\n"); + + *val = le16_to_cpu(tmp); + + return ret; +} + +static int bu27008_get_gain(struct bu27008_data *data, struct iio_gts *gts, int *gain) +{ + int ret, sel; + + ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL2, &sel); + if (ret) + return ret; + + sel = FIELD_GET(BU27008_MASK_RGBC_GAIN, sel); + + ret = iio_gts_find_gain_by_sel(gts, sel); + if (ret < 0) { + dev_err(data->dev, "unknown gain value 0x%x\n", sel); + return ret; + } + + *gain = ret; + + return 0; +} + +static int bu27008_write_gain_sel(struct bu27008_data *data, int sel) +{ + int regval; + + regval = FIELD_PREP(BU27008_MASK_RGBC_GAIN, sel); + + /* + * We do always set also the LOW bits of IR-gain because othervice we + * would risk resulting an invalid GAIN register value. + * + * We could allow setting separate gains for RGBC and IR when the + * values were such that HW could support both gain settings. + * Eg, when the shared bits were same for both gain values. + * + * This, however, has a negligible benefit compared to the increased + * software complexity when we would need to go through the gains + * for both channels separately when the integration time changes. + * This would end up with nasty logic for computing gain values for + * both channels - and rejecting them if shared bits changed. + * + * We should then build the logic by guessing what a user prefers. + * RGBC or IR gains correctly set while other jumps to odd value? + * Maybe look-up a value where both gains are somehow optimized + * <what this somehow is, is ATM unknown to us>. Or maybe user would + * expect us to reject changes when optimal gains can't be set to both + * channels w/given integration time. At best that would result + * solution that works well for a very specific subset of + * configurations but causes unexpected corner-cases. + * + * So, we keep it simple. Always set same selector to IR and RGBC. + * We disallow setting IR (as I expect that most of the users are + * interested in RGBC). This way we can show the user that the scales + * for RGBC and IR channels are different (1X Vs 2X with sel 0) while + * still keeping the operation deterministic. + */ + regval |= FIELD_PREP(BU27008_MASK_IR_GAIN_LO, sel); + + return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL2, + BU27008_MASK_RGBC_GAIN, regval); +} + +static int bu27008_set_gain(struct bu27008_data *data, int gain) +{ + int ret; + + ret = iio_gts_find_sel_by_gain(&data->gts, gain); + if (ret < 0) + return ret; + + return bu27008_write_gain_sel(data, ret); +} + +static int bu27008_get_int_time_sel(struct bu27008_data *data, int *sel) +{ + int ret, val; + + ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL1, &val); + *sel = FIELD_GET(BU27008_MASK_MEAS_MODE, val); + + return ret; +} + +static int bu27008_set_int_time_sel(struct bu27008_data *data, int sel) +{ + return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL1, + BU27008_MASK_MEAS_MODE, sel); +} + +static int bu27008_get_int_time(struct bu27008_data *data) +{ + int ret, sel; + + ret = bu27008_get_int_time_sel(data, &sel); + if (ret) + return ret; + + return iio_gts_find_int_time_by_sel(&data->gts, + sel & BU27008_MASK_MEAS_MODE); +} + +static int _bu27008_get_scale(struct bu27008_data *data, bool ir, int *val, + int *val2) +{ + struct iio_gts *gts; + int gain, ret; + + if (ir) + gts = &data->gts_ir; + else + gts = &data->gts; + + ret = bu27008_get_gain(data, gts, &gain); + if (ret) + return ret; + + ret = bu27008_get_int_time(data); + if (ret < 0) + return ret; + + return iio_gts_get_scale(gts, gain, ret, val, val2); +} + +static int bu27008_get_scale(struct bu27008_data *data, bool ir, int *val, + int *val2) +{ + int ret; + + mutex_lock(&data->mutex); + ret = _bu27008_get_scale(data, ir, val, val2); + mutex_unlock(&data->mutex); + + return ret; +} + +static int bu27008_set_int_time(struct bu27008_data *data, int time) +{ + int ret; + + ret = iio_gts_find_sel_by_int_time(&data->gts, time); + if (ret < 0) + return ret; + + return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL1, + BU27008_MASK_MEAS_MODE, ret); +} + +/* Try to change the time so that the scale is maintained */ +static int bu27008_try_set_int_time(struct bu27008_data *data, int int_time_new) +{ + int ret, old_time_sel, new_time_sel, old_gain, new_gain; + + mutex_lock(&data->mutex); + + ret = bu27008_get_int_time_sel(data, &old_time_sel); + if (ret < 0) + goto unlock_out; + + if (!iio_gts_valid_time(&data->gts, int_time_new)) { + dev_dbg(data->dev, "Unsupported integration time %u\n", + int_time_new); + + ret = -EINVAL; + goto unlock_out; + } + new_time_sel = iio_gts_find_sel_by_int_time(&data->gts, int_time_new); + if (new_time_sel == old_time_sel) { + ret = 0; + goto unlock_out; + } + + ret = bu27008_get_gain(data, &data->gts, &old_gain); + if (ret) + goto unlock_out; + + ret = iio_gts_find_new_gain_sel_by_old_gain_time(&data->gts, old_gain, + old_time_sel, new_time_sel, &new_gain); + if (ret) { + int scale1, scale2; + bool ok; + + _bu27008_get_scale(data, false, &scale1, &scale2); + dev_dbg(data->dev, + "Can't support time %u with current scale %u %u\n", + int_time_new, scale1, scale2); + + if (new_gain < 0) + goto unlock_out; + + /* + * If caller requests for integration time change and we + * can't support the scale - then the caller should be + * prepared to 'pick up the pieces and deal with the + * fact that the scale changed'. + */ + ret = iio_find_closest_gain_low(&data->gts, new_gain, &ok); + if (!ok) + dev_dbg(data->dev, "optimal gain out of range\n"); + + if (ret < 0) { + dev_dbg(data->dev, + "Total gain increase. Risk of saturation"); + ret = iio_gts_get_min_gain(&data->gts); + if (ret < 0) + goto unlock_out; + } + new_gain = ret; + dev_dbg(data->dev, "scale changed, new gain %u\n", new_gain); + } + + ret = bu27008_set_gain(data, new_gain); + if (ret) + goto unlock_out; + + ret = bu27008_set_int_time(data, int_time_new); + +unlock_out: + mutex_unlock(&data->mutex); + + return ret; +} + +static int bu27008_meas_set(struct bu27008_data *data, int state) +{ + return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL3, + BU27008_MASK_MEAS_EN, state); +} + +static int bu27008_chan_cfg(struct bu27008_data *data, + struct iio_chan_spec const *chan) +{ + int chan_sel; + + if (chan->scan_index == BU27008_BLUE) + chan_sel = BU27008_BLUE2_CLEAR3; + else + chan_sel = BU27008_CLEAR2_IR3; + + chan_sel = FIELD_PREP(BU27008_MASK_CHAN_SEL, chan_sel); + + return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL3, + BU27008_MASK_CHAN_SEL, chan_sel); +} + +static int bu27008_read_one(struct bu27008_data *data, struct iio_dev *idev, + struct iio_chan_spec const *chan, int *val, int *val2) +{ + int ret, int_time; + + ret = bu27008_chan_cfg(data, chan); + if (ret) + return ret; + + ret = bu27008_meas_set(data, BU27008_MEAS_EN); + if (ret) + return ret; + + int_time = bu27008_get_int_time(data); + if (int_time < 0) + int_time = 400000; + + msleep((int_time + 500) / 1000); + + ret = bu27008_chan_read_data(data, chan->address, val); + if (!ret) + ret = IIO_VAL_INT; + + if (bu27008_meas_set(data, BU27008_MEAS_DIS)) + dev_warn(data->dev, "measurement disabling failed\n"); + + return ret; +} + +static int bu27008_read_raw(struct iio_dev *idev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct bu27008_data *data = iio_priv(idev); + int busy, ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + { + busy = iio_device_claim_direct_mode(idev); + if (busy) + return -EBUSY; + + mutex_lock(&data->mutex); + ret = bu27008_read_one(data, idev, chan, val, val2); + mutex_unlock(&data->mutex); + + iio_device_release_direct_mode(idev); + + return ret; + } + case IIO_CHAN_INFO_SCALE: + ret = bu27008_get_scale(data, chan->scan_index == BU27008_IR, + val, val2); + if (ret) + return ret; + + return IIO_VAL_INT_PLUS_NANO; + + case IIO_CHAN_INFO_INT_TIME: + ret = bu27008_get_int_time(data); + if (ret < 0) + return ret; + + *val = 0; + *val2 = ret; + + return IIO_VAL_INT_PLUS_MICRO; + + default: + return -EINVAL; + } +} + +static int bu27008_set_scale(struct bu27008_data *data, + struct iio_chan_spec const *chan, + int val, int val2) +{ + int ret, gain_sel, time_sel, i; + + if (chan->scan_index == BU27008_IR) + return -EINVAL; + + mutex_lock(&data->mutex); + + ret = bu27008_get_int_time_sel(data, &time_sel); + if (ret < 0) + goto unlock_out; + + + ret = iio_gts_find_gain_sel_for_scale_using_time(&data->gts, time_sel, + val, val2 * 1000, &gain_sel); + if (ret) { + /* Could not support new scale with existing int-time */ + int new_time_sel; + + for (i = 0; i < data->gts.num_itime; i++) { + new_time_sel = data->gts.itime_table[i].sel; + ret = iio_gts_find_gain_sel_for_scale_using_time( + &data->gts, new_time_sel, val, val2 * 1000, + &gain_sel); + if (!ret) + break; + } + if (i == data->gts.num_itime) { + dev_err(data->dev, "Can't support scale %u %u\n", val, + val2); + + ret = -EINVAL; + goto unlock_out; + } + + ret = bu27008_set_int_time_sel(data, new_time_sel); + if (ret) + goto unlock_out; + } + + ret = bu27008_write_gain_sel(data, gain_sel); + +unlock_out: + mutex_unlock(&data->mutex); + + return ret; +} + +static int bu27008_write_raw(struct iio_dev *idev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct bu27008_data *data = iio_priv(idev); + int ret; + + /* + * We should not allow changing scale when measurement is ongoing. + * This could make values in buffer inconsistent. + */ + ret = iio_device_claim_direct_mode(idev); + if (ret) + return ret; + + switch (mask) { + case IIO_CHAN_INFO_SCALE: + ret = bu27008_set_scale(data, chan, val, val2); + break; + case IIO_CHAN_INFO_INT_TIME: + if (val) + ret = -EINVAL; + else + ret = bu27008_try_set_int_time(data, val2); + break; + default: + ret = -EINVAL; + break; + } + iio_device_release_direct_mode(idev); + + return ret; +} + +static int bu27008_read_avail(struct iio_dev *idev, + struct iio_chan_spec const *chan, const int **vals, + int *type, int *length, long mask) +{ + struct bu27008_data *data = iio_priv(idev); + + switch (mask) { + case IIO_CHAN_INFO_INT_TIME: + return iio_gts_avail_times(&data->gts, vals, type, length); + case IIO_CHAN_INFO_SCALE: + if (chan->channel2 == IIO_MOD_LIGHT_IR) + return iio_gts_all_avail_scales(&data->gts_ir, vals, + type, length); + return iio_gts_all_avail_scales(&data->gts, vals, type, length); + default: + return -EINVAL; + } +} + +static const struct iio_info bu27008_info = { + .read_raw = &bu27008_read_raw, + .write_raw = &bu27008_write_raw, + .read_avail = &bu27008_read_avail, + .validate_trigger = iio_validate_own_trigger, +}; + +static int bu27008_chip_init(struct bu27008_data *data) +{ + int ret; + + ret = regmap_update_bits(data->regmap, BU27008_REG_SYSTEM_CONTROL, + BU27008_MASK_SW_RESET, BU27008_MASK_SW_RESET); + if (ret) + return dev_err_probe(data->dev, ret, "Sensor reset failed\n"); + + /* + * The data-sheet does not tell how long performing the IC reset takes. + * However, the data-sheet says the minimum time it takes the IC to be + * able to take inputs after power is applied, is 100 uS. I'd assume + * > 1 mS is enough. + */ + msleep(1); + + return ret; +} + +static int bu27008_set_drdy_irq(struct bu27008_data *data, int state) +{ + return regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL3, + BU27008_MASK_INT_EN, state); +} + +static int bu27008_trigger_set_state(struct iio_trigger *trig, + bool state) +{ + struct bu27008_data *data = iio_trigger_get_drvdata(trig); + int ret = 0; + + if (state) + ret = bu27008_set_drdy_irq(data, BU27008_INT_EN); + else + ret = bu27008_set_drdy_irq(data, BU27008_INT_DIS); + if (ret) + dev_err(data->dev, "Failed to set trigger state\n"); + + return ret; +} + +static const struct iio_trigger_ops bu27008_trigger_ops = { + .set_trigger_state = bu27008_trigger_set_state, +}; + +static irqreturn_t bu27008_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *idev = pf->indio_dev; + struct bu27008_data *data = iio_priv(idev); + struct { + __le16 chan[BU27008_NUM_HW_CHANS]; + s64 ts __aligned(8); + } raw; + int ret, dummy; + + memset(&raw, 0, sizeof(raw)); + + /* + * After some measurements, it seems reading the + * BU27008_REG_MODE_CONTROL3 debounces the IRQ line + */ + ret = regmap_read(data->regmap, BU27008_REG_MODE_CONTROL3, &dummy); + if (ret < 0) + goto err_read; + + ret = regmap_bulk_read(data->regmap, BU27008_REG_DATA0_LO, &raw.chan, + sizeof(raw.chan)); + if (ret < 0) + goto err_read; + + iio_push_to_buffers_with_timestamp(idev, &raw, pf->timestamp); +err_read: + iio_trigger_notify_done(idev->trig); + + return IRQ_HANDLED; +} + +static irqreturn_t bu27008_irq_thread_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *idev = pf->indio_dev; + struct bu27008_data *data = iio_priv(idev); + + iio_trigger_poll_nested(data->trig); + + return IRQ_HANDLED; +} + +static int bu27008_buffer_preenable(struct iio_dev *idev) +{ + struct bu27008_data *data = iio_priv(idev); + int chan_sel, ret; + + /* Configure channel selection */ + if (test_bit(BU27008_BLUE, idev->active_scan_mask)) { + if (test_bit(BU27008_CLEAR, idev->active_scan_mask)) + chan_sel = BU27008_BLUE2_CLEAR3; + else + chan_sel = BU27008_BLUE2_IR3; + } else { + chan_sel = BU27008_CLEAR2_IR3; + } + + chan_sel = FIELD_PREP(BU27008_MASK_CHAN_SEL, chan_sel); + + ret = regmap_update_bits(data->regmap, BU27008_REG_MODE_CONTROL3, + BU27008_MASK_CHAN_SEL, chan_sel); + if (ret) + return ret; + + return bu27008_meas_set(data, BU27008_MEAS_EN); +} + +static int bu27008_buffer_postdisable(struct iio_dev *idev) +{ + struct bu27008_data *data = iio_priv(idev); + + return bu27008_meas_set(data, BU27008_MEAS_DIS); +} + +static const struct iio_buffer_setup_ops bu27008_buffer_ops = { + .preenable = bu27008_buffer_preenable, + .postdisable = bu27008_buffer_postdisable, +}; + +static int bu27008_probe(struct i2c_client *i2c) +{ + struct device *dev = &i2c->dev; + struct iio_trigger *itrig; + struct bu27008_data *data; + struct regmap *regmap; + unsigned int part_id, reg; + struct iio_dev *idev; + char *name; + int ret; + + if (!i2c->irq) + dev_warn(dev, "No IRQ configured\n"); + + regmap = devm_regmap_init_i2c(i2c, &bu27008_regmap); + if (IS_ERR(regmap)) + return dev_err_probe(dev, PTR_ERR(regmap), + "Failed to initialize Regmap\n"); + + idev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!idev) + return -ENOMEM; + + ret = devm_regulator_get_enable(dev, "vdd"); + if (ret) + return dev_err_probe(dev, ret, "Failed to get regulator\n"); + + data = iio_priv(idev); + + ret = regmap_read(regmap, BU27008_REG_SYSTEM_CONTROL, ®); + if (ret) + return dev_err_probe(dev, ret, "Failed to access sensor\n"); + + part_id = FIELD_GET(BU27008_MASK_PART_ID, reg); + + if (part_id != BU27008_ID) + dev_warn(dev, "unknown device 0x%x\n", part_id); + + ret = devm_iio_init_iio_gts(dev, BU27008_SCALE_1X, 0, bu27008_gains, + ARRAY_SIZE(bu27008_gains), bu27008_itimes, + ARRAY_SIZE(bu27008_itimes), &data->gts); + if (ret) + return ret; + + ret = devm_iio_init_iio_gts(dev, BU27008_SCALE_1X, 0, bu27008_gains_ir, + ARRAY_SIZE(bu27008_gains_ir), bu27008_itimes, + ARRAY_SIZE(bu27008_itimes), &data->gts_ir); + if (ret) + return ret; + + mutex_init(&data->mutex); + data->regmap = regmap; + data->dev = dev; + data->irq = i2c->irq; + + idev->channels = bu27008_channels; + idev->num_channels = ARRAY_SIZE(bu27008_channels); + idev->name = "bu27008"; + idev->info = &bu27008_info; + idev->modes = INDIO_DIRECT_MODE; + idev->available_scan_masks = bu27008_scan_masks; + + ret = bu27008_chip_init(data); + if (ret) + return ret; + + if (i2c->irq) { + ret = devm_iio_triggered_buffer_setup(dev, idev, + &iio_pollfunc_store_time, + bu27008_trigger_handler, + &bu27008_buffer_ops); + if (ret) + return dev_err_probe(dev, ret, + "iio_triggered_buffer_setup_ext FAIL\n"); + + itrig = devm_iio_trigger_alloc(dev, "%sdata-rdy-dev%d", + idev->name, iio_device_id(idev)); + if (!itrig) + return -ENOMEM; + + data->trig = itrig; + + itrig->ops = &bu27008_trigger_ops; + iio_trigger_set_drvdata(itrig, data); + + name = devm_kasprintf(dev, GFP_KERNEL, "%s-bu27008", + dev_name(dev)); + + ret = devm_request_threaded_irq(dev, i2c->irq, + iio_pollfunc_store_time, + &bu27008_irq_thread_handler, + IRQF_ONESHOT, name, idev->pollfunc); + if (ret) + return dev_err_probe(dev, ret, + "Could not request IRQ\n"); + + + ret = devm_iio_trigger_register(dev, itrig); + if (ret) + return dev_err_probe(dev, ret, + "Trigger registration failed\n"); + } + + ret = devm_iio_device_register(dev, idev); + if (ret) + return dev_err_probe(dev, ret, + "Unable to register iio device\n"); + + return ret; +} + +static const struct of_device_id bu27008_of_match[] = { + { .compatible = "rohm,bu27008", }, + { } +}; +MODULE_DEVICE_TABLE(of, bu27008_of_match); + +static struct i2c_driver bu27008_i2c_driver = { + .driver = { + .name = "bu27008", + .of_match_table = bu27008_of_match, + }, + .probe_new = bu27008_probe, +}; +module_i2c_driver(bu27008_i2c_driver); + +MODULE_DESCRIPTION("ROHM BU27008 colour sensor driver"); +MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS(IIO_GTS_HELPER);
The ROHM BU27008 is a sensor with 5 photodiodes (red, green, blue, clear and IR) with four configurable channels. Red and green being always available and two out of the rest three (blue, clear, IR) can be selected to be simultaneously measured. Typical application is adjusting LCD backlight of TVs, mobile phones and tablet PCs. Add initial support for the ROHM BU27008 color sensor. - raw_read() of RGB and clear channels - triggered buffer w/ DRDY interrtupt Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> --- Revision history v1 => v2: drivers/iio/light/rohm-bu27008.c - Fix buffered data demuxing - Use generic trigger functions instead of rolling own ones - Drop unnecessary locking - Use generic iio_validate_own_trigger() - Some other more trivial fixes for review comments - use defines for [enable/disable] [measurement/data-ready IRQ] reg values and use regmap_update_bits() directly instead of regamap_[set/clear]_bits() --- drivers/iio/light/Kconfig | 14 + drivers/iio/light/Makefile | 1 + drivers/iio/light/rohm-bu27008.c | 964 +++++++++++++++++++++++++++++++ 3 files changed, 979 insertions(+) create mode 100644 drivers/iio/light/rohm-bu27008.c