On Sat, 22 Sep 2018 10:42:44 +0100 Jonathan Cameron <ji...@kernel.org> wrote:
> A few follow ups to the discussion here from me.. > > Note it's helpful to crop and email and no one really minds if you > just act on their review without acknowledging it (so cut the > bits you fully agree with out too - saves on scrolling / reading time ;) > > A catch all, "Agree with everything else and will fix for v2" covers > everything you don't want to discuss further. > (not that I'm great at doing this either :( > ... > > > > diff --git a/drivers/iio/magnetometer/rm3100-core.c > > > > b/drivers/iio/magnetometer/rm3100-core.c > > > > new file mode 100644 > > > > index 000000000000..55d515e0fe67 > > > > --- /dev/null > > > > +++ b/drivers/iio/magnetometer/rm3100-core.c > > > > @@ -0,0 +1,399 @@ > > > > +// SPDX-License-Identifier: GPL-2.0+ > > > > +/* > > > > + * PNI RM3100 9-axis geomagnetic sensor driver core. > > > > + * > > > > + * Copyright (C) 2018 Song Qiang <songqiang1304...@gmail.com> > > > > + * > > > > + * User Manual available at > > > > + * <https://www.pnicorp.com/download/rm3100-user-manual/> > > > > + * > > > > + * TODO: Scale channel, event generaton, pm. > > > > > > at least read support for _SCALE is mandatory, IMHO > > > > > > > Okay, I'll add it in next version. > > > Just for the record, it's only mandatory in cases where > it is known (you'd be amazed how often we only know the value is monotonic) > > Now as you put it in the todo list, it's presumably known here > hence Peter's comment :) > > (just avoiding setting precedence) > > > > ... > > > > +static const struct regmap_range rm3100_readable_ranges[] = { > > > > + regmap_reg_range(RM_W_REG_START, RM_W_REG_END), > > > > +}; > > > > + > > > > +const struct regmap_access_table rm3100_readable_table = { > > > > > > static > > > > > > > I was planning to let rm3100-i2c.c and rm3100-spi.c to share these 6 > > structures, because the only different configuration of regmap between > > these two files lies in 'struct regmap_config'. To achieve this, I have > > to expose these 3 structures to be referenced in rm3100-i2c.c and > > rm3100-spi.c > > Since *_common_probe() and *_common_remove() are exposed, I thought it > > was fine to expose these structures to reduce redundant code, is this > > prohibited? > Nope, but are you doing it in this patch? + you need to export the > symbols if you are going to do that otherwise modular builds > will fail to probe (and possibly build - I can't recall and am too > lazy to check this morning - not enough coffee yet!) > > .. > > > > + *val = le32_to_cpu((buffer[0] << 16) + (buffer[1] << 8) + > > > > buffer[2]); > > > > > > no need for le32_to_cpu() > > > > > > > I think I didn't fully understand this, I'll look into it. > > > > To point you in the right direction here. When you explicitly pull out > individual bytes like you are doing here, you are getting them in a particular > endian order. Shifts and adding (though normally convention is | when doing > this) are done in machine endianness, hence the *val is already in the > endian type of your cpu. > > > > > + *val = sign_extend32(*val, 23); > > > > + > > > > + return IIO_VAL_INT; > > > > +} > > > > + > > > > +#define RM_CHANNEL(axis, idx) \ > > > > > > use RM3100_ prefix please > > > > > > > In the last driver I wrote, name of registers are so long that I have to > > suppress them as possible as I can, it seems like this one doesn't need > > to. :) > > > > > > + { > > > > \ > > > > + .type = IIO_MAGN, > > > > \ > > > > + .modified = 1, > > > > \ > > > > + .channel2 = IIO_MOD_##axis, > > > > \ > > > > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > > > > \ > > > > + .info_mask_shared_by_type = > > > > BIT(IIO_CHAN_INFO_SAMP_FREQ),\ > > > > + .scan_index = idx, > > > > \ > > > > + .scan_type = { > > > > \ > > > > + .sign = 's', > > > > \ > > > > + .realbits = 24, > > > > \ > > > > + .storagebits = 32, > > > > \ > > > > + .shift = 8, > > > > \ > > > > + .endianness = IIO_LE, > > > > \ > > > > + }, > > > > \ > > > > + } > > > > + > > > > +static const struct iio_chan_spec rm3100_channels[] = { > > > > + RM_CHANNEL(X, 0), > > > > + RM_CHANNEL(Y, 1), > > > > + RM_CHANNEL(Z, 2), > > > > + IIO_CHAN_SOFT_TIMESTAMP(3), > > > > +}; > > > > + > > > > +static const unsigned long rm3100_scan_masks[] = {GENMASK(2, 0), 0}; > > > > + > > > > +#define RM_SAMP_NUM 14 > > > > > > prefix > > > > > > > + > > > > +/* Frequency : rm3100_samp_rates[][0].rm3100_samp_rates[][1]Hz. > > > > + * Time between reading: rm3100_sam_rates[][2]ms (The first on is > > > > actially 1.7). > > > > > > one > > > actually > > > 1.7 what unit? > > > > > > > It's in milliseconds. These time values are used for lookup so I do not > > need to compute time between conversion from measurement frequency, and > > they are used for wait time, I thought a little longer is better. > > I think the comment above this structure isn't very clear, I'll find a > > better way to explain it. > Please also use kernel standard comment syntax > > /* > * Frequency... > */ > > > > ... > > > > + if (i != RM_SAMP_NUM) { > > > > + mutex_lock(&data->lock); > > > > + ret = regmap_write(regmap, RM_REG_TMRC, i + > > > > RM_TMRC_OFFSET); > > > > + if (ret < 0) > > > > > > unlock? > > > > > > > These actions are for changing the sampling frequency. This device > > cannot start conversion if CMM register is not reset after reading from > > CCX/CCY/CCZ registers. So I unlock it later since conversion should have > > already been stopped and other threads should not access the bus. > Hmm. If you are holding the lock across function calls you need > to look at lockdep annotations. > > Also, I suspect something is wrong here as you are unlocking in > the good path but not the bad one which seems unlikely to be > as intended... > > > > > > > + return ret; > > > > + > > > > + /* Checking if cycle count registers need changing. */ > > > > + if (val == 600 && cycle_count == 200) { > > > > + for (i = 0; i < 3; i++) { > > > > + regmap_write(regmap, RM_REG_CCXL + 2 * > > > > i, 100); > > > > + if (ret < 0) > > > > > > unlock? > > > > > > > + return ret; > > > > + } > > > > + } else if (val != 600 && cycle_count == 100) { > > > > + for (i = 0; i < 3; i++) { > > > > + regmap_write(regmap, RM_REG_CCXL + 2 * > > > > i, 200); > > > > + if (ret < 0) > > > > > > unlock? > > > > > > > + return ret; > > > > + } > > > > + } > > > > + /* Writing TMRC registers requires CMM reset. */ > > > > + ret = regmap_write(regmap, RM_REG_CMM, 0); > > > > + if (ret < 0) > > > > > > unlock? > > > > > > > + return ret; > > > > + ret = regmap_write(regmap, RM_REG_CMM, RM_CMM_PMX | > > > > + RM_CMM_PMY | RM_CMM_PMZ | RM_CMM_START); > > > > + if (ret < 0) > > > > > > unlock? > > > > > > > + return ret; > > > > + mutex_unlock(&data->lock); > > > > + > > > > + data->conversion_time = rm3100_samp_rates[i][2] + 3000; > > > > + return 0; > > > > + } > > > > + return -EINVAL; > > > > +} > > > > + > > > > +static int rm3100_read_raw(struct iio_dev *indio_dev, > > > > + const struct iio_chan_spec *chan, > > > > + int *val, int *val2, long mask) > > > > +{ > > > > + struct rm3100_data *data = iio_priv(indio_dev); > > > > + int ret; > > > > + > > > > + switch (mask) { > > > > + case IIO_CHAN_INFO_RAW: > > > > + ret = iio_device_claim_direct_mode(indio_dev); > > > > + if (ret < 0) > > > > > > release_direct_mode() here? > > > > > > > Oh..yes! > > This should have stopped you reading more than once so I'm surprised > this slipped through. I guess the usual last minute change problem ;) > (we all do it however much we know we should retest properly) Ah. Just realised. Error path :) > > Jonathan
