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Re: [PATCH] spi/rockchip: Make sure spi clk is on in rockchip_spi_set_cs

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  Re: [PATCH] spi/rockchip: Make sure spi clk is on in  rockchip_spi_set_cs Mark Brown <broonie@kernel.org> - 2016-03-05 13:50 +0100

#1350886 — Re: [PATCH] spi/rockchip: Make sure spi clk is on in rockchip_spi_set_cs

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On Fri, Feb 26, 2016 at 10:31:50AM +0800, Huang, Tao wrote:

> You misunderstand me. I talk about spi_setup, as
> Documentation/spi/spi-summary, which would normally be called from
> probe() before the first I/O is done to the device.
> spi_setup will call spi_set_cs(spi, false), which introduced with commit
> 1a7b7ee72c21 ("spi: Ensure that CS line is in non-active state after
> spi_setup()"). And spi_set_cs will call spi->master->set_cs, and set_cs
> callback will access register. Without clk enable, I believe some
> drivers will failed to run.

That's definitely very driver specific, a large proportion of devices
don't manage their chip selects via the SPI controller at all.

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