[PATCH v2 2/3] soc: rockchip: add driver handling grf setup

Doug Anderson dianders at chromium.org
Wed Nov 16 13:50:56 PST 2016


On Tue, Nov 15, 2016 at 2:38 PM, Heiko Stuebner <heiko at sntech.de> wrote:
> The General Register Files are an area of registers containing a lot
> of single-bit settings for numerous components as well full components
> like usbphy control. Therefore all used components are accessed
> via the syscon provided by the grf nodes or from the sub-devices
> created through the simple-mfd created from the grf node.
> Some settings are not used by anything but will need to be set up
> according to expectations on the kernel side.
> Best example is the force_jtag setting, which defaults to on and
> results in the soc switching the pin-outputs between jtag and sdmmc
> automatically depending on the card-detect status. This conflicts
> heavily with how the dw_mmc driver expects to do its work and also
> with the clock-controller, which has most likely deactivated the
> jtag clock due to it being unused.
> So far the handling of this setting was living in the mach-rockchip
> code for the arm32-based rk3288 but that of course doesn't work
> for arm64 socs and would also look ugly for further arm32 socs.
> Also always disabling this setting is quite specific to linux and
> its subsystems, other operating systems might prefer other settings,
> so that the bootloader cannot really set a sane default for all.
> So introduce a top-level driver for the grf that handles these
> settings that need to be a certain way but nobody cares about.
> Other needed settings might surface in the future and can then
> be added here, but only as a last option. Ideally general GRF
> settings should be handled in the driver needing them.
> Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> ---
>  drivers/soc/rockchip/Kconfig  |  10 ++++
>  drivers/soc/rockchip/Makefile |   1 +
>  drivers/soc/rockchip/grf.c    | 134 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 145 insertions(+)

Other than the header file stuff pointed out by Shawn, this looks good
to me now.

Reviewed-by: Douglas Anderson <dianders at chromium.org>

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