[U-Boot] [PATCH] spi: tegra: fix hand in set_mode()

[Simon Glass]

Hi Stephen,

On 18 August 2016 at 10:53, Stephen Warren <swarren at wwwdotorg.org> wrote:
> From: Stephen Warren <swarren at nvidia.com>
>
> In tegra20_slink.c, the set_mode() function may be executed before the
> SPI bus is claimed the first time, and hence the clocks to the SPI
> controller may not be running. If so, any register read/write at this
> time will hang the CPU. Fix this by ensuring the clock is running as soon
> as the driver is probed. This is observed on the Tegra30 Beaver board.
>
> Apply the same clock initialization fix to all other Tegra SPI drivers so
> that if set_mode() is ever implemented there, the same bug will not appear.
> Note that tegra114_spi.c already operates in this fashion.
>
> The clock manipulation code is copied from claim_bus() to probe() rather
> than moved. This ensures that any calls to set_speed() take effect; the
> clock can't be set once during probe and left unchanged.
>
> Fixes: 5cb1b7b395c0 ("spi: tegra20: Add support for mode selection")
> Cc: Mirza Krak <mirza.krak at hostmobility.com>
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
>  drivers/spi/tegra20_sflash.c | 4 ++++
>  drivers/spi/tegra20_slink.c  | 4 ++++
>  drivers/spi/tegra210_qspi.c  | 3 +++
>  3 files changed, 11 insertions(+)

Reviewed-by: Simon Glass <sjg at chromium.org>

You might consider storing the mode and not acting on it until later.
But this is fine.

Regards,
Simon