On Sun, 28 Oct 2018 13:23:23 +0530
Nishad Kamdar <nishadkam...@gmail.com> wrote:

> Replace platform data with device tree support.
> 
> Signed-off-by: Nishad Kamdar <nishadkam...@gmail.com>
The whole gpio in or out thing makes less and less sense to
me and seems to contradict the datasheet.

If I'm not missing something I would just get rid of the option.
If I am missing something (not hard in the datasheet which, whilst
fairly clear, is a rather long ;)

Jonathan

> ---
>  drivers/staging/iio/resolver/Kconfig    |  1 +
>  drivers/staging/iio/resolver/ad2s1210.c | 17 ++++++++---------
>  drivers/staging/iio/resolver/ad2s1210.h | 17 -----------------
>  3 files changed, 9 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/staging/iio/resolver/Kconfig 
> b/drivers/staging/iio/resolver/Kconfig
> index 6a469ee6101f..cc1202ff813d 100644
> --- a/drivers/staging/iio/resolver/Kconfig
> +++ b/drivers/staging/iio/resolver/Kconfig
> @@ -15,6 +15,7 @@ config AD2S90
>  
>  config AD2S1210
>       tristate "Analog Devices ad2s1210 driver"
> +     depends on OF
>       depends on SPI
>       depends on GPIOLIB || COMPILE_TEST
>       help
> diff --git a/drivers/staging/iio/resolver/ad2s1210.c 
> b/drivers/staging/iio/resolver/ad2s1210.c
> index 0234869e9d74..5ecdb5785132 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.c
> +++ b/drivers/staging/iio/resolver/ad2s1210.c
> @@ -17,6 +17,7 @@
>  #include <linux/delay.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/module.h>
> +#include <linux/of.h>
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> @@ -76,7 +77,6 @@ struct ad2s1210_gpio {
>  };
>  
>  struct ad2s1210_state {
> -     const struct ad2s1210_platform_data *pdata;
>       struct mutex lock;
>       struct spi_device *sdev;
>       struct gpio_desc *sample;
> @@ -84,6 +84,7 @@ struct ad2s1210_state {
>       struct gpio_desc *a1;
>       struct gpio_desc *res0;
>       struct gpio_desc *res1;
> +     bool gpioin;
>       unsigned int fclkin;
>       unsigned int fexcit;
>       bool hysteresis;
> @@ -314,7 +315,7 @@ static ssize_t ad2s1210_store_control(struct device *dev,
>       }
>       st->resolution
>               = ad2s1210_resolution_value[data & AD2S1210_SET_RESOLUTION];
> -     if (st->pdata->gpioin) {
> +     if (st->gpioin) {
>               data = ad2s1210_read_resolution_pin(st);
>               if (data != st->resolution)
>                       dev_warn(dev, "ad2s1210: resolution settings not 
> match\n");
> @@ -376,7 +377,7 @@ static ssize_t ad2s1210_store_resolution(struct device 
> *dev,
>       }
>       st->resolution
>               = ad2s1210_resolution_value[data & AD2S1210_SET_RESOLUTION];
> -     if (st->pdata->gpioin) {
> +     if (st->gpioin) {
>               data = ad2s1210_read_resolution_pin(st);
>               if (data != st->resolution)
>                       dev_warn(dev, "ad2s1210: resolution settings not 
> match\n");
> @@ -603,7 +604,7 @@ static int ad2s1210_initial(struct ad2s1210_state *st)
>       int ret;
>  
>       mutex_lock(&st->lock);
> -     if (st->pdata->gpioin)
> +     if (st->gpioin)
>               st->resolution = ad2s1210_read_resolution_pin(st);
>       else
>               ad2s1210_set_resolution_pin(st);
> @@ -644,7 +645,7 @@ static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
>       int ret, i;
>       struct spi_device *spi = st->sdev;
>       struct ad2s1210_gpio *pin;
> -     unsigned long flags = st->pdata->gpioin ? GPIOD_IN : GPIOD_OUT_LOW;
> +     unsigned long flags = st->gpioin ? GPIOD_IN : GPIOD_OUT_LOW;
>  
>       struct ad2s1210_gpio gpios[] = {
>               { .ptr = &st->sample, .name = "sample", .flags = GPIOD_IN },
> @@ -673,16 +674,14 @@ static int ad2s1210_probe(struct spi_device *spi)
>  {
>       struct iio_dev *indio_dev;
>       struct ad2s1210_state *st;
> +     struct device_node *np = spi->dev.of_node;
>       int ret;
>  
> -     if (!spi->dev.platform_data)
> -             return -EINVAL;
> -
>       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
>       if (!indio_dev)
>               return -ENOMEM;
>       st = iio_priv(indio_dev);
> -     st->pdata = spi->dev.platform_data;
> +     st->gpioin = of_property_read_bool(np, "gpioin");

Hmm. This bothered me in the earlier patch.  How are we meant to configure
these pins... (and this time I actually loaded the datasheet)

A0 and A1 always seem to be control signals written to the device so
I don't really understand why we would ever want them to be 'inputs'
on our host.

RES0 and RES1 are also control signals. Clearly marked as logic inputs.

The only thing I can think here is there is an evaluation board out there
were we are not in control of these, some other controller is.
That is a pretty weird board if so, hence I would only support the version
where we use GPIO outputs from the host.

This will further simplify patch 1 and get rid fo the need for this
non standard bit of devicetree binding.


>       ret = ad2s1210_setup_gpios(st);
>       if (ret < 0)
>               return ret;
> diff --git a/drivers/staging/iio/resolver/ad2s1210.h 
> b/drivers/staging/iio/resolver/ad2s1210.h
> index 63d479b20a6c..e69de29bb2d1 100644
> --- a/drivers/staging/iio/resolver/ad2s1210.h
> +++ b/drivers/staging/iio/resolver/ad2s1210.h
> @@ -1,17 +0,0 @@
> -/*
> - * ad2s1210.h plaform data for the ADI Resolver to Digital Converters:
> - * AD2S1210
> - *
> - * Copyright (c) 2010-2010 Analog Devices Inc.
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License version 2 as
> - * published by the Free Software Foundation.
> - */
> -#ifndef _AD2S1210_H
> -#define _AD2S1210_H
> -
> -struct ad2s1210_platform_data {
> -     bool                    gpioin;
> -};
> -#endif /* _AD2S1210_H */

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