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Date: Tue, 21 Jul 2020 21:40:44 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Alexandru Ardelean <alexandru.ardelean@...log.com>,
linux-iio <linux-iio@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] iio: adc: ad7124: move chip ID & name on the chip_info table
On Mon, Jul 20, 2020 at 2:30 PM Jonathan Cameron <jic23@...nel.org> wrote:
>
> On Tue, 14 Jul 2020 08:11:11 +0300
> Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:
>
> > This change does the following:
> > * removes the SPI device table in favor of the OF device table
> > * adds 'name' && 'chip_id' fields to chip_info
> > * implements chip ID & silicon revision checking; the device ID for
> > AD7124-4 is 0x0, so just checking that value can be useless;
> > but at least the silicon revision isn't 0, so a non-zero value can be
> > used to check that "a" device is on the SPI bus; it's probably the best
> > way to narrow it down to one of the 2 AD7124 chip IDs
> >
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
> Nice patch.
Doesn't this patch bring an opposite to what you are trying to clean up, i.e.
of_get_match_data(), of_device.h?
> Applied to the togreg branch of iio.git and pushed out as testing for
> the auto builders to play with it.
>
> At somepoint we could think about moving this driver over to generic
> fw interfaces, but that is a bigger job and no particular reason to
> do that now (if it's even possible!)
>
> Thanks,
>
> Jonathan
>
> > ---
> > drivers/iio/adc/ad7124.c | 73 ++++++++++++++++++++++++++++++++--------
> > 1 file changed, 59 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
> > index bb53ab265b64..8dce06e9e69c 100644
> > --- a/drivers/iio/adc/ad7124.c
> > +++ b/drivers/iio/adc/ad7124.c
> > @@ -12,6 +12,7 @@
> > #include <linux/interrupt.h>
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > +#include <linux/of_device.h>
> > #include <linux/regulator/consumer.h>
> > #include <linux/spi/spi.h>
> >
> > @@ -47,6 +48,15 @@
> > #define AD7124_ADC_CTRL_MODE_MSK GENMASK(5, 2)
> > #define AD7124_ADC_CTRL_MODE(x) FIELD_PREP(AD7124_ADC_CTRL_MODE_MSK, x)
> >
> > +/* AD7124 ID */
> > +#define AD7124_DEVICE_ID_MSK GENMASK(7, 4)
> > +#define AD7124_DEVICE_ID_GET(x) FIELD_GET(AD7124_DEVICE_ID_MSK, x)
> > +#define AD7124_SILICON_REV_MSK GENMASK(3, 0)
> > +#define AD7124_SILICON_REV_GET(x) FIELD_GET(AD7124_SILICON_REV_MSK, x)
> > +
> > +#define CHIPID_AD7124_4 0x0
> > +#define CHIPID_AD7124_8 0x1
> > +
> > /* AD7124_CHANNEL_X */
> > #define AD7124_CHANNEL_EN_MSK BIT(15)
> > #define AD7124_CHANNEL_EN(x) FIELD_PREP(AD7124_CHANNEL_EN_MSK, x)
> > @@ -120,6 +130,8 @@ static const char * const ad7124_ref_names[] = {
> > };
> >
> > struct ad7124_chip_info {
> > + const char *name;
> > + unsigned int chip_id;
> > unsigned int num_inputs;
> > };
> >
> > @@ -165,9 +177,13 @@ static const struct iio_chan_spec ad7124_channel_template = {
> >
> > static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
> > [ID_AD7124_4] = {
> > + .name = "ad7127-4",
> > + .chip_id = CHIPID_AD7124_4,
> > .num_inputs = 8,
> > },
> > [ID_AD7124_8] = {
> > + .name = "ad7127-8",
> > + .chip_id = CHIPID_AD7124_8,
> > .num_inputs = 16,
> > },
> > };
> > @@ -503,6 +519,34 @@ static int ad7124_soft_reset(struct ad7124_state *st)
> > return -EIO;
> > }
> >
> > +static int ad7124_check_chip_id(struct ad7124_state *st)
> > +{
> > + unsigned int readval, chip_id, silicon_rev;
> > + int ret;
> > +
> > + ret = ad_sd_read_reg(&st->sd, AD7124_ID, 1, &readval);
> > + if (ret < 0)
> > + return ret;
> > +
> > + chip_id = AD7124_DEVICE_ID_GET(readval);
> > + silicon_rev = AD7124_SILICON_REV_GET(readval);
> > +
> > + if (chip_id != st->chip_info->chip_id) {
> > + dev_err(&st->sd.spi->dev,
> > + "Chip ID mismatch: expected %u, got %u\n",
> > + st->chip_info->chip_id, chip_id);
> > + return -ENODEV;
> > + }
> > +
> > + if (silicon_rev == 0) {
> > + dev_err(&st->sd.spi->dev,
> > + "Silicon revision empty. Chip may not be present\n");
> > + return -ENODEV;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int ad7124_init_channel_vref(struct ad7124_state *st,
> > unsigned int channel_number)
> > {
> > @@ -665,25 +709,28 @@ static int ad7124_setup(struct ad7124_state *st)
> >
> > static int ad7124_probe(struct spi_device *spi)
> > {
> > - const struct spi_device_id *id;
> > + const struct ad7124_chip_info *info;
> > struct ad7124_state *st;
> > struct iio_dev *indio_dev;
> > int i, ret;
> >
> > + info = of_device_get_match_data(&spi->dev);
> > + if (!info)
> > + return -ENODEV;
> > +
> > indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > if (!indio_dev)
> > return -ENOMEM;
> >
> > st = iio_priv(indio_dev);
> >
> > - id = spi_get_device_id(spi);
> > - st->chip_info = &ad7124_chip_info_tbl[id->driver_data];
> > + st->chip_info = info;
> >
> > ad_sd_init(&st->sd, indio_dev, spi, &ad7124_sigma_delta_info);
> >
> > spi_set_drvdata(spi, indio_dev);
> >
> > - indio_dev->name = spi_get_device_id(spi)->name;
> > + indio_dev->name = st->chip_info->name;
> > indio_dev->modes = INDIO_DIRECT_MODE;
> > indio_dev->info = &ad7124_info;
> >
> > @@ -721,6 +768,10 @@ static int ad7124_probe(struct spi_device *spi)
> > if (ret < 0)
> > goto error_clk_disable_unprepare;
> >
> > + ret = ad7124_check_chip_id(st);
> > + if (ret)
> > + goto error_clk_disable_unprepare;
> > +
> > ret = ad7124_setup(st);
> > if (ret < 0)
> > goto error_clk_disable_unprepare;
> > @@ -768,16 +819,11 @@ static int ad7124_remove(struct spi_device *spi)
> > return 0;
> > }
> >
> > -static const struct spi_device_id ad7124_id_table[] = {
> > - { "ad7124-4", ID_AD7124_4 },
> > - { "ad7124-8", ID_AD7124_8 },
> > - {}
> > -};
> > -MODULE_DEVICE_TABLE(spi, ad7124_id_table);
> > -
> > static const struct of_device_id ad7124_of_match[] = {
> > - { .compatible = "adi,ad7124-4" },
> > - { .compatible = "adi,ad7124-8" },
> > + { .compatible = "adi,ad7124-4",
> > + .data = &ad7124_chip_info_tbl[ID_AD7124_4], },
> > + { .compatible = "adi,ad7124-8",
> > + .data = &ad7124_chip_info_tbl[ID_AD7124_8], },
> > { },
> > };
> > MODULE_DEVICE_TABLE(of, ad7124_of_match);
> > @@ -789,7 +835,6 @@ static struct spi_driver ad71124_driver = {
> > },
> > .probe = ad7124_probe,
> > .remove = ad7124_remove,
> > - .id_table = ad7124_id_table,
> > };
> > module_spi_driver(ad71124_driver);
> >
>
--
With Best Regards,
Andy Shevchenko
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