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 <drink...@chromium.org>
Acked-by: Leilk Liu <leilk....@mediatek.com>
> ---
>
> 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;
> + }
> }
> }
> }
--
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