[PATCH 1/3] iio: adc: ad7887: convert dual-channel mode to DT/ACPI

[PATCH 1/3] iio: adc: ad7887: convert dual-channel mode to DT/ACPI

[Alexandru Ardelean]

This change converts the configuration of the dual-channel mode from the
old platform-data, to the device_property_present() function, which
supports both device-tree and ACPI configuration setups.

With this change the old platform_data include of the driver can be
removed.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/iio/adc/ad7887.c             | 10 +++++-----
 include/linux/platform_data/ad7887.h | 21 ---------------------
 2 files changed, 5 insertions(+), 26 deletions(-)
 delete mode 100644 include/linux/platform_data/ad7887.h

diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c
index 4f6f0e0e03ee..06f684c053a0 100644
--- a/drivers/iio/adc/ad7887.c
+++ b/drivers/iio/adc/ad7887.c
@@ -23,8 +23,6 @@
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 
-#include <linux/platform_data/ad7887.h>
-
 #define AD7887_REF_DIS		BIT(5)	/* on-chip reference disable */
 #define AD7887_DUAL		BIT(4)	/* dual-channel mode */
 #define AD7887_CH_AIN1		BIT(3)	/* convert on channel 1, DUAL=1 */
@@ -241,9 +239,9 @@ static void ad7887_reg_disable(void *data)
 
 static int ad7887_probe(struct spi_device *spi)
 {
-	struct ad7887_platform_data *pdata = spi->dev.platform_data;
 	struct ad7887_state *st;
 	struct iio_dev *indio_dev;
+	bool dual_mode;
 	uint8_t mode;
 	int ret;
 
@@ -286,7 +284,9 @@ static int ad7887_probe(struct spi_device *spi)
 	mode = AD7887_PM_MODE4;
 	if (!st->reg)
 		mode |= AD7887_REF_DIS;
-	if (pdata && pdata->en_dual)
+
+	dual_mode = device_property_present(&spi->dev, "adi,dual-channel-mode");
+	if (dual_mode)
 		mode |= AD7887_DUAL;
 
 	st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
@@ -298,7 +298,7 @@ static int ad7887_probe(struct spi_device *spi)
 	spi_message_init(&st->msg[AD7887_CH0]);
 	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
 
-	if (pdata && pdata->en_dual) {
+	if (dual_mode) {
 		st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
 
 		st->xfer[1].rx_buf = &st->data[0];
diff --git a/include/linux/platform_data/ad7887.h b/include/linux/platform_data/ad7887.h
deleted file mode 100644
index 9b4dca6ae70b..000000000000
--- a/include/linux/platform_data/ad7887.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * AD7887 SPI ADC driver
- *
- * Copyright 2010 Analog Devices Inc.
- */
-#ifndef IIO_ADC_AD7887_H_
-#define IIO_ADC_AD7887_H_
-
-/**
- * struct ad7887_platform_data - AD7887 ADC driver platform data
- * @en_dual: Whether to use dual channel mode. If set to true AIN1 becomes the
- *	second input channel, and Vref is internally connected to Vdd. If set to
- *	false the device is used in single channel mode and AIN1/Vref is used as
- *	VREF input.
- */
-struct ad7887_platform_data {
-	bool en_dual;
-};
-
-#endif /* IIO_ADC_AD7887_H_ */
-- 
2.17.1

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

[Alexandru Ardelean]

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>
---
 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);
 
-- 
2.17.1

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

[Jonathan Cameron]

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);
>  

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

[Jonathan Cameron]

On Tue, 17 Nov 2020 11:01:11 +0000
Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:

> 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.

Having said that.... Why are we going through this dance for driver with
only one compatible?   Are there other parts on their way?
If not, perhaps we should just rip out the matching code entirely in
the interests of simplicity.

Jonathan

> 
> 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);
> >    
> 

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

[Alexandru Ardelean]

On Tue, Nov 17, 2020 at 1:06 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Tue, 17 Nov 2020 11:01:11 +0000
> Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:
>
> > 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.
>
> Having said that.... Why are we going through this dance for driver with
> only one compatible?   Are there other parts on their way?
> If not, perhaps we should just rip out the matching code entirely in
> the interests of simplicity.

So, this one has a bit of a funny story.
There's an AD7888 which is similar in terms of registers but with more channels.
Lars did a patch to support it on top of AD7887:
    https://github.com/analogdevicesinc/linux/commits/iio-ad7888

We tried to order a part for this to test the changes, but we got a
reply that it's obsolete.
The website says it is still in production.
So, I was confused about the answer we got. ¯\_(ツ)_/¯

In the meantime, I thought I'd take some of the cleanup value of Lars'
work and do the cleanup only.
We may still find that part somewhere and maybe add it, or maybe
another one would come along.
I don't know at this point. I'm mostly looking at some of my backlog
stuff and trying to cleanup old stuff.

I'm fine to simplify the driver now and add the matching bits later.

>
> Jonathan
>
> >
> > 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);
> > >
> >
>

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

[Jonathan Cameron]

On Tue, 17 Nov 2020 17:03:06 +0200
Alexandru Ardelean <ardeleanalex@gmail.com> wrote:

> On Tue, Nov 17, 2020 at 1:06 PM Jonathan Cameron
> <Jonathan.Cameron@huawei.com> wrote:
> >
> > On Tue, 17 Nov 2020 11:01:11 +0000
> > Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:
> >  
> > > 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.  
> >
> > Having said that.... Why are we going through this dance for driver with
> > only one compatible?   Are there other parts on their way?
> > If not, perhaps we should just rip out the matching code entirely in
> > the interests of simplicity.  
> 
> So, this one has a bit of a funny story.
> There's an AD7888 which is similar in terms of registers but with more channels.
> Lars did a patch to support it on top of AD7887:
>     https://github.com/analogdevicesinc/linux/commits/iio-ad7888
> 
> We tried to order a part for this to test the changes, but we got a
> reply that it's obsolete.
> The website says it is still in production.
> So, I was confused about the answer we got. ¯\_(ツ)_/¯
> 
> In the meantime, I thought I'd take some of the cleanup value of Lars'
> work and do the cleanup only.
> We may still find that part somewhere and maybe add it, or maybe
> another one would come along.
> I don't know at this point. I'm mostly looking at some of my backlog
> stuff and trying to cleanup old stuff.
> 
> I'm fine to simplify the driver now and add the matching bits later.

Sounds good to me.

> 
> >
> > Jonathan
> >  
> > >
> > > 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);
> > > >  
> > >  
> >  

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

[Alexandru Ardelean]

On Tue, Nov 17, 2020 at 6:02 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Tue, 17 Nov 2020 17:03:06 +0200
> Alexandru Ardelean <ardeleanalex@gmail.com> wrote:
>
> > On Tue, Nov 17, 2020 at 1:06 PM Jonathan Cameron
> > <Jonathan.Cameron@huawei.com> wrote:
> > >
> > > On Tue, 17 Nov 2020 11:01:11 +0000
> > > Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:
> > >
> > > > 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.
> > >
> > > Having said that.... Why are we going through this dance for driver with
> > > only one compatible?   Are there other parts on their way?
> > > If not, perhaps we should just rip out the matching code entirely in
> > > the interests of simplicity.
> >
> > So, this one has a bit of a funny story.
> > There's an AD7888 which is similar in terms of registers but with more channels.
> > Lars did a patch to support it on top of AD7887:
> >     https://github.com/analogdevicesinc/linux/commits/iio-ad7888
> >
> > We tried to order a part for this to test the changes, but we got a
> > reply that it's obsolete.
> > The website says it is still in production.
> > So, I was confused about the answer we got. ¯\_(ツ)_/¯
> >
> > In the meantime, I thought I'd take some of the cleanup value of Lars'
> > work and do the cleanup only.
> > We may still find that part somewhere and maybe add it, or maybe
> > another one would come along.
> > I don't know at this point. I'm mostly looking at some of my backlog
> > stuff and trying to cleanup old stuff.
> >
> > I'm fine to simplify the driver now and add the matching bits later.
>
> Sounds good to me.

I'm a bit vague on the message of this reply.
Should I simplify it or leave it as-is?

>
> >
> > >
> > > Jonathan
> > >
> > > >
> > > > 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);
> > > > >
> > > >
> > >
>

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

[Jonathan Cameron]

On Wed, 18 Nov 2020 14:59:39 +0200
Alexandru Ardelean <ardeleanalex@gmail.com> wrote:

> On Tue, Nov 17, 2020 at 6:02 PM Jonathan Cameron
> <Jonathan.Cameron@huawei.com> wrote:
> >
> > On Tue, 17 Nov 2020 17:03:06 +0200
> > Alexandru Ardelean <ardeleanalex@gmail.com> wrote:
> >  
> > > On Tue, Nov 17, 2020 at 1:06 PM Jonathan Cameron
> > > <Jonathan.Cameron@huawei.com> wrote:  
> > > >
> > > > On Tue, 17 Nov 2020 11:01:11 +0000
> > > > Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:
> > > >  
> > > > > 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.  
> > > >
> > > > Having said that.... Why are we going through this dance for driver with
> > > > only one compatible?   Are there other parts on their way?
> > > > If not, perhaps we should just rip out the matching code entirely in
> > > > the interests of simplicity.  
> > >
> > > So, this one has a bit of a funny story.
> > > There's an AD7888 which is similar in terms of registers but with more channels.
> > > Lars did a patch to support it on top of AD7887:
> > >     https://github.com/analogdevicesinc/linux/commits/iio-ad7888
> > >
> > > We tried to order a part for this to test the changes, but we got a
> > > reply that it's obsolete.
> > > The website says it is still in production.
> > > So, I was confused about the answer we got. ¯\_(ツ)_/¯
> > >
> > > In the meantime, I thought I'd take some of the cleanup value of Lars'
> > > work and do the cleanup only.
> > > We may still find that part somewhere and maybe add it, or maybe
> > > another one would come along.
> > > I don't know at this point. I'm mostly looking at some of my backlog
> > > stuff and trying to cleanup old stuff.
> > >
> > > I'm fine to simplify the driver now and add the matching bits later.  
> >
> > Sounds good to me.  
> 
> I'm a bit vague on the message of this reply.
> Should I simplify it or leave it as-is?
oops.  Simplify it as then we don't have to worry about dealing with the
greybus case.

Jonathan

> 
> >  
> > >  
> > > >
> > > > Jonathan
> > > >  
> > > > >
> > > > > 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);
> > > > > >  
> > > > >  
> > > >  
> >  

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

[Andy Shevchenko]

On Tue, Nov 17, 2020 at 1:01 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> 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.

device_get_match_data() doesn't know about bus type specifics. One may
introduce a helper like

const void *spi_device_get_match_data(dev)
{
  const void *match = device_get_match_data(dev);
  if (match)
    return match;
  return spi_dev_id....;
}

And use it with the SPI ID table.

-- 
With Best Regards,
Andy Shevchenko

[PATCH 3/3] dt-bindings: adc: ad7887: add binding doc for AD7887

[Alexandru Ardelean]

This change adds a simple device-tree binding for thhe Analog Devices
AD7887 ADC.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 .../bindings/iio/adc/adi,ad7887.yaml          | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml
new file mode 100644
index 000000000000..9b30f4569b4e
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml
@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7887.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7887 low power, 12-bit ADC
+
+maintainers:
+  - Michael Hennerich <michael.hennerich@analog.com>
+
+description: |
+  Analog Devices AD7887 low power, 12-bit analog-to-digital converter (ADC)
+  that operates from a single 2.7 V to 5.25 V power supply.
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7887
+
+  reg:
+    maxItems: 1
+
+  spi-cpha: true
+
+  spi-cpol: true
+
+  avcc-supply: true
+
+  spi-max-frequency: true
+
+  vref-supply:
+    description:
+      ADC reference voltage supply
+
+  adi,dual-channel-mode:
+    description:
+      Configures dual-channel mode for the ADC. In dual-channel operation,
+      the AIN1/VREF pin assumes its AIN1 function, providing a second analog
+      input channel. In this case, he reference voltage for the part is provided
+      via the VDD pin. As a result, the input voltage range on both the AIN0 and
+      AIN1 inputs is 0 to VDD.
+    type: boolean
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - spi-cpha
+  - spi-cpol
+
+examples:
+  - |
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+                compatible = "adi,ad7887";
+                reg = <0>;
+                spi-max-frequency = <1000000>;
+                spi-cpol;
+                spi-cpha;
+
+                avcc-supply = <&adc_supply>;
+                vref-supply = <&adc_vref>;
+        };
+    };
+...
-- 
2.17.1

Re: [PATCH 3/3] dt-bindings: adc: ad7887: add binding doc for AD7887

[Jonathan Cameron]

On Tue, 17 Nov 2020 09:52:54 +0200
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:

> This change adds a simple device-tree binding for thhe Analog Devices
> AD7887 ADC.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>

Binding looks good to me.

Jonathan

> ---
>  .../bindings/iio/adc/adi,ad7887.yaml          | 70 +++++++++++++++++++
>  1 file changed, 70 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml
> new file mode 100644
> index 000000000000..9b30f4569b4e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7887.yaml
> @@ -0,0 +1,70 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/adi,ad7887.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices AD7887 low power, 12-bit ADC
> +
> +maintainers:
> +  - Michael Hennerich <michael.hennerich@analog.com>
> +
> +description: |
> +  Analog Devices AD7887 low power, 12-bit analog-to-digital converter (ADC)
> +  that operates from a single 2.7 V to 5.25 V power supply.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ad7887
> +
> +  reg:
> +    maxItems: 1
> +
> +  spi-cpha: true
> +
> +  spi-cpol: true
> +
> +  avcc-supply: true
> +
> +  spi-max-frequency: true
> +
> +  vref-supply:
> +    description:
> +      ADC reference voltage supply
> +
> +  adi,dual-channel-mode:
> +    description:
> +      Configures dual-channel mode for the ADC. In dual-channel operation,
> +      the AIN1/VREF pin assumes its AIN1 function, providing a second analog
> +      input channel. In this case, he reference voltage for the part is provided
> +      via the VDD pin. As a result, the input voltage range on both the AIN0 and
> +      AIN1 inputs is 0 to VDD.
> +    type: boolean
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - spi-cpha
> +  - spi-cpol
> +
> +examples:
> +  - |
> +    spi0 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        adc@0 {
> +                compatible = "adi,ad7887";
> +                reg = <0>;
> +                spi-max-frequency = <1000000>;
> +                spi-cpol;
> +                spi-cpha;
> +
> +                avcc-supply = <&adc_supply>;
> +                vref-supply = <&adc_vref>;
> +        };
> +    };
> +...

Re: [PATCH 1/3] iio: adc: ad7887: convert dual-channel mode to DT/ACPI

[Jonathan Cameron]

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

> This change converts the configuration of the dual-channel mode from the
> old platform-data, to the device_property_present() function, which
> supports both device-tree and ACPI configuration setups.
> 
> With this change the old platform_data include of the driver can be
> removed.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Hi Alex,

I'm a bit in too minds about device_property_present()
vs device_property_read_bool() which are the same thing under the hood.

Not sure which one conveys the correct semantics here.
I don't feel strongly enough about it though to do more than raise
eyebrows (i.e. not blocking this series).

Jonathan

> ---
>  drivers/iio/adc/ad7887.c             | 10 +++++-----
>  include/linux/platform_data/ad7887.h | 21 ---------------------
>  2 files changed, 5 insertions(+), 26 deletions(-)
>  delete mode 100644 include/linux/platform_data/ad7887.h
> 
> diff --git a/drivers/iio/adc/ad7887.c b/drivers/iio/adc/ad7887.c
> index 4f6f0e0e03ee..06f684c053a0 100644
> --- a/drivers/iio/adc/ad7887.c
> +++ b/drivers/iio/adc/ad7887.c
> @@ -23,8 +23,6 @@
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/triggered_buffer.h>
>  
> -#include <linux/platform_data/ad7887.h>
> -
>  #define AD7887_REF_DIS		BIT(5)	/* on-chip reference disable */
>  #define AD7887_DUAL		BIT(4)	/* dual-channel mode */
>  #define AD7887_CH_AIN1		BIT(3)	/* convert on channel 1, DUAL=1 */
> @@ -241,9 +239,9 @@ static void ad7887_reg_disable(void *data)
>  
>  static int ad7887_probe(struct spi_device *spi)
>  {
> -	struct ad7887_platform_data *pdata = spi->dev.platform_data;
>  	struct ad7887_state *st;
>  	struct iio_dev *indio_dev;
> +	bool dual_mode;
>  	uint8_t mode;
>  	int ret;
>  
> @@ -286,7 +284,9 @@ static int ad7887_probe(struct spi_device *spi)
>  	mode = AD7887_PM_MODE4;
>  	if (!st->reg)
>  		mode |= AD7887_REF_DIS;
> -	if (pdata && pdata->en_dual)
> +
> +	dual_mode = device_property_present(&spi->dev, "adi,dual-channel-mode");

It ends up as the same thing internally but sort of feels like
device_property_read_bool() might be a better fit?

I assume device_property_present() will return true for say
adi,dual-channel-mode = <3>;
whereas in my head device_property_read_bool should at very least
print a warning on that (it doesn't :)



> +	if (dual_mode)
>  		mode |= AD7887_DUAL;
>  
>  	st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
> @@ -298,7 +298,7 @@ static int ad7887_probe(struct spi_device *spi)
>  	spi_message_init(&st->msg[AD7887_CH0]);
>  	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
>  
> -	if (pdata && pdata->en_dual) {
> +	if (dual_mode) {
>  		st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
>  
>  		st->xfer[1].rx_buf = &st->data[0];
> diff --git a/include/linux/platform_data/ad7887.h b/include/linux/platform_data/ad7887.h
> deleted file mode 100644
> index 9b4dca6ae70b..000000000000
> --- a/include/linux/platform_data/ad7887.h
> +++ /dev/null
> @@ -1,21 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0-or-later */
> -/*
> - * AD7887 SPI ADC driver
> - *
> - * Copyright 2010 Analog Devices Inc.
> - */
> -#ifndef IIO_ADC_AD7887_H_
> -#define IIO_ADC_AD7887_H_
> -
> -/**
> - * struct ad7887_platform_data - AD7887 ADC driver platform data
> - * @en_dual: Whether to use dual channel mode. If set to true AIN1 becomes the
> - *	second input channel, and Vref is internally connected to Vdd. If set to
> - *	false the device is used in single channel mode and AIN1/Vref is used as
> - *	VREF input.
> - */
> -struct ad7887_platform_data {
> -	bool en_dual;
> -};
> -
> -#endif /* IIO_ADC_AD7887_H_ */

Re: [PATCH 1/3] iio: adc: ad7887: convert dual-channel mode to DT/ACPI

[Andy Shevchenko]

On Tue, Nov 17, 2020 at 12:42 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Tue, 17 Nov 2020 09:52:52 +0200
> Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
>
> > This change converts the configuration of the dual-channel mode from the
> > old platform-data, to the device_property_present() function, which
> > supports both device-tree and ACPI configuration setups.
> >
> > With this change the old platform_data include of the driver can be
> > removed.
> >
> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> Hi Alex,
>
> I'm a bit in too minds about device_property_present()
> vs device_property_read_bool() which are the same thing under the hood.
>
> Not sure which one conveys the correct semantics here.
> I don't feel strongly enough about it though to do more than raise
> eyebrows (i.e. not blocking this series).

The idea as I understand it is that the 'present' can be run against
any type of property, while 'bool' is specifically for boolean (the
similarities is a detail of implementation).

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/3] iio: adc: ad7887: convert dual-channel mode to DT/ACPI

[Alexandru Ardelean]

On Tue, Nov 17, 2020 at 1:10 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Tue, Nov 17, 2020 at 12:42 PM Jonathan Cameron
> <Jonathan.Cameron@huawei.com> wrote:
> >
> > On Tue, 17 Nov 2020 09:52:52 +0200
> > Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
> >
> > > This change converts the configuration of the dual-channel mode from the
> > > old platform-data, to the device_property_present() function, which
> > > supports both device-tree and ACPI configuration setups.
> > >
> > > With this change the old platform_data include of the driver can be
> > > removed.
> > >
> > > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> > Hi Alex,
> >
> > I'm a bit in too minds about device_property_present()
> > vs device_property_read_bool() which are the same thing under the hood.
> >
> > Not sure which one conveys the correct semantics here.
> > I don't feel strongly enough about it though to do more than raise
> > eyebrows (i.e. not blocking this series).
>
> The idea as I understand it is that the 'present' can be run against
> any type of property, while 'bool' is specifically for boolean (the
> similarities is a detail of implementation).

Yeah, I'm also not sure which to use here.
I guess I got used to using device_property_present() a bit more.
They're both pretty used around other drivers.
I guess I'll leave it as is for now, unless other complaints.


>
> --
> With Best Regards,
> Andy Shevchenko