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SubjectRe: [PATCH] spi: Make GPIO CSs honour the SPI_NO_CS flag
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On Fri, 2018-10-12 at 10:23 +0100, Phil Elwell wrote:
> The SPI configuration state includes an SPI_NO_CS flag that disables
> all CS line manipulation, for applications that want to manage their
> own chip selects. However, this flag is ignored by the GPIO CS code
> in the SPI framework.

> @@ -729,7 +729,9 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
> enable = !enable;
>
> if (gpio_is_valid(spi->cs_gpio)) {
> - gpio_set_value(spi->cs_gpio, !enable);
> + /* Honour the SPI_NO_CS flag */
> + if (!(spi->mode & SPI_NO_CS))
> + gpio_set_value(spi->cs_gpio, !enable);
> /* Some SPI masters need both GPIO CS & slave_select */
> if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
> spi->controller->set_cs)

What about the calls to spi->controller->set_cs() after this? Should a
driver provided set_cs method be responsible for checking SPI_NO_CS?
Or should it not be called in the first place?

I imagine it depends on what set_cs needs to do, which might not be
solely related to changing the CS line.
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