2015-11-09 04:14:59

by Nicolas Boichat

Subject: [PATCH v2] spi: mediatek: single device does not require cs_gpios

When only one device is present, it is not necessary to specify
cs_gpios, as the CS line can be controlled by the hardware
module.

Without this patch, older device tree bindings used before
37457607 "spi: mediatek: mt8173 spi multiple devices support"
would cause a panic on boot. This fixes the crash, and
re-introduces backward compatibility.

Signed-off-by: Nicolas Boichat <[email protected]>
---

v2: Use gpio_is_valid()

Applies on top of broonie/spi.git/for-next.

drivers/spi/spi-mt65xx.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 563954a..7840067 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -410,7 +410,7 @@ static int mtk_spi_setup(struct spi_device *spi)
if (!spi->controller_data)
spi->controller_data = (void *)&mtk_default_chip_info;

- if (mdata->dev_comp->need_pad_sel)
+ if (mdata->dev_comp->need_pad_sel && gpio_is_valid(spi->cs_gpio))
gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));

return 0;
@@ -632,13 +632,23 @@ static int mtk_spi_probe(struct platform_device *pdev)
goto err_put_master;
}

- for (i = 0; i < master->num_chipselect; i++) {
- ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i],
- dev_name(&pdev->dev));
- if (ret) {
- dev_err(&pdev->dev,
- "can't get CS GPIO %i\n", i);
- goto err_put_master;
+ if (!master->cs_gpios && master->num_chipselect > 1) {
+ dev_err(&pdev->dev,
+ "cs_gpios not specified and num_chipselect > 1\n");
+ ret = -EINVAL;
+ goto err_put_master;
+ }
+
+ if (master->cs_gpios) {
+ for (i = 0; i < master->num_chipselect; i++) {
+ ret = devm_gpio_request(&pdev->dev,
+ master->cs_gpios[i],
+ dev_name(&pdev->dev));
+ if (ret) {
+ dev_err(&pdev->dev,
+ "can't get CS GPIO %i\n", i);
+ goto err_put_master;
+ }
}
}
}
--
2.6.0.rc2.230.g3dd15c0

2015-11-14 02:27:30

by Leilk Liu

Subject: Re: [PATCH v2] spi: mediatek: single device does not require cs_gpios

On Mon, 2015-11-09 at 12:14 +0800, Nicolas Boichat wrote:
> When only one device is present, it is not necessary to specify
> cs_gpios, as the CS line can be controlled by the hardware
> module.
>
> Without this patch, older device tree bindings used before
> 37457607 "spi: mediatek: mt8173 spi multiple devices support"
> would cause a panic on boot. This fixes the crash, and
> re-introduces backward compatibility.
>
> Signed-off-by: Nicolas Boichat <[email protected]>

Acked-by: Leilk Liu <[email protected]>

> ---
>
> v2: Use gpio_is_valid()
>
> Applies on top of broonie/spi.git/for-next.
>
> drivers/spi/spi-mt65xx.c | 26 ++++++++++++++++++--------
> 1 file changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
> index 563954a..7840067 100644
> --- a/drivers/spi/spi-mt65xx.c
> +++ b/drivers/spi/spi-mt65xx.c
> @@ -410,7 +410,7 @@ static int mtk_spi_setup(struct spi_device *spi)
> if (!spi->controller_data)
> spi->controller_data = (void *)&mtk_default_chip_info;
>
> - if (mdata->dev_comp->need_pad_sel)
> + if (mdata->dev_comp->need_pad_sel && gpio_is_valid(spi->cs_gpio))
> gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
>
> return 0;
> @@ -632,13 +632,23 @@ static int mtk_spi_probe(struct platform_device *pdev)
> goto err_put_master;
> }
>
> - for (i = 0; i < master->num_chipselect; i++) {
> - ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i],
> - dev_name(&pdev->dev));
> - if (ret) {
> - dev_err(&pdev->dev,
> - "can't get CS GPIO %i\n", i);
> - goto err_put_master;
> + if (!master->cs_gpios && master->num_chipselect > 1) {
> + dev_err(&pdev->dev,
> + "cs_gpios not specified and num_chipselect > 1\n");
> + ret = -EINVAL;
> + goto err_put_master;
> + }
> +
> + if (master->cs_gpios) {
> + for (i = 0; i < master->num_chipselect; i++) {
> + ret = devm_gpio_request(&pdev->dev,
> + master->cs_gpios[i],
> + dev_name(&pdev->dev));
> + if (ret) {
> + dev_err(&pdev->dev,
> + "can't get CS GPIO %i\n", i);
> + goto err_put_master;
> + }
> }
> }
> }

2015-11-17 10:49:19

by Matthias Brugger

Subject: Re: [PATCH v2] spi: mediatek: single device does not require cs_gpios

On 14/11/15 03:27, lei liu wrote:
> On Mon, 2015-11-09 at 12:14 +0800, Nicolas Boichat wrote:
>> When only one device is present, it is not necessary to specify
>> cs_gpios, as the CS line can be controlled by the hardware
>> module.
>>
>> Without this patch, older device tree bindings used before
>> 37457607 "spi: mediatek: mt8173 spi multiple devices support"
>> would cause a panic on boot. This fixes the crash, and
>> re-introduces backward compatibility.
>>
>> Signed-off-by: Nicolas Boichat <[email protected]>
>
> Acked-by: Leilk Liu <[email protected]>
>

Please make sure this fix get applied to v4.3 as well.

Thanks,
Matthias