Re: [PATCH 2/3] iio: adc: ad7887: convert driver to full DT probing

Jonathan Cameron
2020-11-17T11:01:55Z

On Tue, 17 Nov 2020 09:52:53 +0200
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:

> This change removes the SPI device table, adds an OF device table instead.
> This should also be usable for ACPI via PRP0001.
>
> This device is usually probed via device-tree, so it makes more sense to
> use the OF device table.
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
So, we've had a few cases of having to put the device_id table
back again recently.
https://lore.kernel.org/linux-iio/20201101152613.2c37581a@archlinux/

They tend to be due to greybus doing it's probing in yet another fashion.
So far they've been all i2c devices, but I kind of assume it does the same for spi.
https://elixir.bootlin.com/linux/latest/source/drivers/staging/greybus/spilib.c#L437

How device_get_match_data() plays with that I'm not sure. It probably
doesn't right now given swnode doesn't have a device_get_match_data() callback.

https://elixir.bootlin.com/linux/latest/source/drivers/base/swnode.c#L539

So after all that I think I've argued myself around to thinking what you have
here is fine. If someone wants to support this via a swnode then they can
figure out how to make that work.

+CC Vaishnav and Andy for their input.

Otherwise looks fine to me.

Thanks,

Jonathan

> ---
> drivers/iio/adc/ad7887.c | 23 +++++++++++++++--------
> 1 file changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c
> index 06f684c053a0..4f68a1b17ec8 100644
> --- a/drivers/iio/adc/ad7887.c
> +++ b/drivers/iio/adc/ad7887.c
> @@ -40,6 +40,7 @@ enum ad7887_channels {
>
> /**
> * struct ad7887_chip_info - chip specifc information
> + * @name: the name of the part
> * @int_vref_mv: the internal reference voltage
> * @channels: channels specification
> * @num_channels: number of channels
> @@ -47,6 +48,7 @@ enum ad7887_channels {
> * @num_dual_channels: number of channels in dual mode
> */
> struct ad7887_chip_info {
> + const char *name;
> u16 int_vref_mv;
> const struct iio_chan_spec *channels;
> unsigned int num_channels;
> @@ -218,6 +220,7 @@ static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
> * More devices added in future
> */
> [ID_AD7887] = {
> + .name = "ad7887",
> .channels = ad7887_channels,
> .num_channels = ARRAY_SIZE(ad7887_channels),
> .dual_channels = ad7887_dual_channels,
> @@ -239,12 +242,17 @@ static void ad7887_reg_disable(void *data)
>
> static int ad7887_probe(struct spi_device *spi)
> {
> + const struct ad7887_chip_info *info;
> struct ad7887_state *st;
> struct iio_dev *indio_dev;
> bool dual_mode;
> uint8_t mode;
> int ret;
>
> + info = device_get_match_data(&spi->dev);
> + if (!info)
> + return -ENODEV;
> +
> indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> if (indio_dev == NULL)
> return -ENOMEM;
> @@ -269,13 +277,12 @@ static int ad7887_probe(struct spi_device *spi)
> return ret;
> }
>
> - st->chip_info =
> - &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
> + st->chip_info = info;
>
> spi_set_drvdata(spi, indio_dev);
> st->spi = spi;
>
> - indio_dev->name = spi_get_device_id(spi)->name;
> + indio_dev->name = st->chip_info->name;
> indio_dev->info = &ad7887_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
>
> @@ -336,18 +343,18 @@ static int ad7887_probe(struct spi_device *spi)
> return devm_iio_device_register(&spi->dev, indio_dev);
> }
>
> -static const struct spi_device_id ad7887_id[] = {
> - {"ad7887", ID_AD7887},
> - {}
> +static const struct of_device_id ad7887_of_match[] = {
> + { .compatible = "adi,ad7887", .data = &ad7887_chip_info_tbl[ID_AD7887] },
> + { }
> };
> -MODULE_DEVICE_TABLE(spi, ad7887_id);
> +MODULE_DEVICE_TABLE(of, ad7887_of_match);
>
> static struct spi_driver ad7887_driver = {
> .driver = {
> .name = "ad7887",
> + .of_match_table = ad7887_of_match,
> },
> .probe = ad7887_probe,
> - .id_table = ad7887_id,
> };
> module_spi_driver(ad7887_driver);
>