On Tue, 6 Feb 2018 14:46:47 +0100
Tomas Novotny <tomas@xxxxxxxxxx> wrote:
> Hi Peter,
>
> On Mon, 5 Feb 2018 20:55:30 +0100 (CET)
> Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx> wrote:
>
> > On Mon, 5 Feb 2018, Tomas Novotny wrote:
> >
> > > VCNL4200 is an integrated long distance (up to 1500mm) proximity and
> > > ambient light sensor.
> > >
> > > The support is very basic. There is no configuration of proximity and
> > > ambient light sensing yet. Only the reading of both measured values is
> > > done.
> >
> > I think the main issue is the lack of a data ready flag; most drivers
> > return new samples (and wait for a new sample if necessary) -- the
> > VCNL4200 hardware does not seem to support that directly
>
> There are only integration times defined in the datasheet.
>
> > one way would be to use a timer and wait the integration time if
> > necessary, not sure if this mandatory for IIO -- having both semantics in
>
> me neither... Would be enough just to export the integration time via channel
> info?
This is not an unheard of situation unfortunately. Right now I'm
struggling to remember when we last hit this but has definitely come up before.
So I 'think' we are putting the sensor in a free running mode here
and the issue Peter raises is that we can't tell if we have
'fresh' data or not.
For that you can take the approach taken in various sensors which
are on demand triggered - but with a restriction in the minimum time between
readings - this is common in humidity and gas sensors IIRC.
So what you do is record the time of a particular reading and then
check if the new reading is 'too' close to the previous time. If it is
you sleep a bit. This is only ever approximate though as with clock
drifts you will eventually either miss a reading or get get a repeat
(just not the vast majority of the time).
Supporting both forms in driver is fine - semantically from a userspace
point of view it won't be able to tell the difference.
Exporting integration time (and being able to control it) is good
but doesn't prevent userspace from ignoring it and getting invalid
data.
Looks like for the proximity we can run it in an ondemand mode
but not the ALS..
Strange question though - what is the mysterious 'white' channel?
(in the datasheet)
>
> > one driver may be confusing
> >
> > some more suggestions below
> >
> > regards, p.
> >
> > > Signed-off-by: Tomas Novotny <tomas@xxxxxxxxxx>
> > > ---
> > > drivers/iio/light/Kconfig | 5 +--
> > > drivers/iio/light/vcnl4000.c | 72 ++++++++++++++++++++++++++++++++++++++++++--
> > > 2 files changed, 72 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> > > index 2356ed9285df..cab222fa8d18 100644
> > > --- a/drivers/iio/light/Kconfig
> > > +++ b/drivers/iio/light/Kconfig
> > > @@ -396,11 +396,12 @@ config US5182D
> > > will be called us5182d.
> > >
> > > config VCNL4000
> > > - tristate "VCNL4000/4010/4020 combined ALS and proximity sensor"
> > > + tristate "VCNL4000/4010/4020/4200 combined ALS and proximity sensor"
> > > depends on I2C
> > > help
> > > Say Y here if you want to build a driver for the Vishay VCNL4000,
> > > - VCNL4010, VCNL4020 combined ambient light and proximity sensor.
> > > + VCNL4010, VCNL4020, VCNL4200 combined ambient light and proximity
> > > + sensor.
> > >
> > > To compile this driver as a module, choose M here: the
> > > module will be called vcnl4000.
> > > diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> > > index d7e43fd9333e..41f5fad50f63 100644
> > > --- a/drivers/iio/light/vcnl4000.c
> > > +++ b/drivers/iio/light/vcnl4000.c
> > > @@ -1,5 +1,5 @@
> > > /*
> > > - * vcnl4000.c - Support for Vishay VCNL4000/4010/4020 combined ambient
> > > + * vcnl4000.c - Support for Vishay VCNL4000/4010/4020/4200 combined ambient
> > > * light and proximity sensor
> > > *
> > > * Copyright 2012 Peter Meerwald <pmeerw@xxxxxxxxxx>
> > > @@ -8,13 +8,15 @@
> > > * the GNU General Public License. See the file COPYING in the main
> > > * directory of this archive for more details.
> > > *
> > > - * IIO driver for VCNL4000 (7-bit I2C slave address 0x13)
> > > + * IIO driver for:
> > > + * VCNL4000/10/20 (7-bit I2C slave address 0x13)
> > > + * VCNL4200 (7-bit I2C slave address 0x51)
> > > *
> > > * TODO:
> > > * allow to adjust IR current
> > > * proximity threshold and event handling
> > > * periodic ALS/proximity measurement (VCNL4010/20)
> > > - * interrupts (VCNL4010/20)
> > > + * interrupts (VCNL4010/20/200)
> >
> > not sure if this notations is very clear; maybe better
> > * interrupts (VCNL4010/20, VCNL4200)
>
> ok.
>
> > > */
> > >
> > > #include <linux/module.h>
> > > @@ -28,6 +30,7 @@
> > > #define VCNL4000_DRV_NAME "vcnl4000"
> > > #define VCNL4000_PROD_ID 0x01
> > > #define VCNL4010_PROD_ID 0x02 /* for VCNL4020, VCNL4010 */
> > > +#define VCNL4200_PROD_ID 0x58
> > >
> > > #define VCNL4000_COMMAND 0x80 /* Command register */
> > > #define VCNL4000_PROD_REV 0x81 /* Product ID and Revision ID */
> > > @@ -40,6 +43,12 @@
> > > #define VCNL4000_PS_MEAS_FREQ 0x89 /* Proximity test signal frequency */
> > > #define VCNL4000_PS_MOD_ADJ 0x8a /* Proximity modulator timing adjustment */
> > >
> > > +#define VCNL4200_AL_CONF 0x00 /* Ambient light configuration */
> > > +#define VCNL4200_PS_CONF1 0x03 /* Proximity configuration */
> > > +#define VCNL4200_PS_DATA 0x08 /* Proximity data */
> > > +#define VCNL4200_AL_DATA 0x09 /* Ambient light data */
> > > +#define VCNL4200_DEV_ID 0x0e /* Device ID, slave address and version */
> > > +
> > > /* Bit masks for COMMAND register */
> > > #define VCNL4000_AL_RDY BIT(6) /* ALS data ready? */
> > > #define VCNL4000_PS_RDY BIT(5) /* proximity data ready? */
> > > @@ -48,6 +57,7 @@
> > >
> > > enum vcnl4000_device_ids {
> > > VCNL4000,
> > > + VCNL4200,
> > > };
> > >
> > > struct vcnl4000_data {
> > > @@ -68,6 +78,7 @@ struct vcnl4000_chip_spec {
> > >
> > > static const struct i2c_device_id vcnl4000_id[] = {
> > > { "vcnl4000", VCNL4000 },
> > > + { "vcnl4200", VCNL4200 },
> > > { }
> > > };
> > > MODULE_DEVICE_TABLE(i2c, vcnl4000_id);
> > > @@ -92,6 +103,33 @@ static int vcnl4000_init(struct vcnl4000_data *data)
> > > return 0;
> > > };
> > >
> > > +static int vcnl4200_init(struct vcnl4000_data *data)
> > > +{
> > > + int ret;
> > > +
> > > + ret = i2c_smbus_read_word_data(data->client, VCNL4200_DEV_ID);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + if ((ret & 0xff) != VCNL4200_PROD_ID)
> > > + return -ENODEV;
> > > +
> > > + data->prod = "VCNL4200";
> > > + data->rev = ret >> 8 & 0xf;
> >
> > I'd add parenthesis for readability (and those who are not superfamiliar
> > with C operator precedence), i.e. (ret >> 8)
>
> I must admit that I was looking at C operator precedence manual to strip the
> unnecessary parenthesis. I will add them back.
>
> > > +
> > > + /* Set defaults and enable both sensors */
> >
> > maybe: both channels, instead of sensors?
>
> ok.
>
> > > + ret = i2c_smbus_write_byte_data(data->client, VCNL4200_AL_CONF, 0x00);
> > > + if (ret < 0)
> > > + return -EIO;
> >
> > why not simply return ret? an error value should in general not be
> > modified but returned as-is
>
> My mistake, I will fix it.
>
> I will post v2.
>
> Thanks for the review,
>
> Tomas
>
> > > + ret = i2c_smbus_write_byte_data(data->client, VCNL4200_PS_CONF1, 0x00);
> > > + if (ret < 0)
> > > + return -EIO;
> > > +
> > > + data->al_scale = 24000;
> > > +
> > > + return 0;
> > > +};
> > > +
> > > static int vcnl4000_measure(struct vcnl4000_data *data, u8 req_mask,
> > > u8 rdy_mask, u8 data_reg, int *val)
> > > {
> > > @@ -138,6 +176,19 @@ static int vcnl4000_measure(struct vcnl4000_data *data, u8 req_mask,
> > > return ret;
> > > }
> > >
> > > +static int vcnl4200_measure(struct vcnl4000_data *data, u8 reg, int *val)
> > > +{
> > > + int ret;
> > > +
> > > + ret = i2c_smbus_read_word_data(data->client, reg);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + *val = ret;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static int vcnl4000_measure_light(struct vcnl4000_data *data, int *val)
> > > {
> > > return vcnl4000_measure(data,
> > > @@ -145,6 +196,11 @@ static int vcnl4000_measure_light(struct vcnl4000_data *data, int *val)
> > > VCNL4000_AL_RESULT_HI, val);
> > > }
> > >
> > > +static int vcnl4200_measure_light(struct vcnl4000_data *data, int *val)
> > > +{
> > > + return vcnl4200_measure(data, VCNL4200_AL_DATA, val);
> > > +}
> > > +
> > > static int vcnl4000_measure_proximity(struct vcnl4000_data *data, int *val)
> > > {
> > > return vcnl4000_measure(data,
> > > @@ -152,12 +208,22 @@ static int vcnl4000_measure_proximity(struct vcnl4000_data *data, int *val)
> > > VCNL4000_PS_RESULT_HI, val);
> > > }
> > >
> > > +static int vcnl4200_measure_proximity(struct vcnl4000_data *data, int *val)
> > > +{
> > > + return vcnl4200_measure(data, VCNL4200_PS_DATA, val);
> > > +}
> > > +
> > > static const struct vcnl4000_chip_spec vcnl4000_chip_spec_cfg[] = {
> > > [VCNL4000] = {
> > > .init = vcnl4000_init,
> > > .measure_light = vcnl4000_measure_light,
> > > .measure_proximity = vcnl4000_measure_proximity,
> > > },
> > > + [VCNL4200] = {
> > > + .init = vcnl4200_init,
> > > + .measure_light = vcnl4200_measure_light,
> > > + .measure_proximity = vcnl4200_measure_proximity,
> > > + },
> > > };
> > >
> > > static const struct iio_chan_spec vcnl4000_channels[] = {
> > >
> >
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