[PATCH linux dev-4.7 v2 0/1] Enable pinctrl to modify SPI1 strap bits

[Kun Yi]

Hi,

Context: re. Andrew's suggestion to a previous RFC proposal[1].

To modify SPI1 mode at runtime, pinctrl subsystem will need to add exception to
the read-only HWSTRAP rule. This patch does precisely that.

Sending this out as a standalone patch since it seems to me this change could
also make boot time SPI1 mode configuration easier. Instead of configuring
the strap bits in mach-aspeed/aspeed.c AND make sure device tree pinctrl
settings match what was configured, with this change device tree entry
should dictate default SPI1 mode regardless of what's set previously. E.g.
following node will be able to configure spi1 in master mode.

&spi1 {
        status = "okay";

        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_spi1_default>;
};

I saw Joel sent out a patch that configures SPI1 to master for every AST2500
machine, do we not have any uses currently for other modes?

[1] https://lists.ozlabs.org/pipermail/openbmc/2016-October/005194.html

Thanks,
Kun

Changes since v1:

- Allowed modifying partial bits of SPI1 strap bitmask instead of strictly
  allowing only bitmask == BIT[13:12] to go through
- Rename HW_STRAP_RESET to HW_STRAP_CLEAR and removed (to be obsoleted) macro

Kun Yi (1):
  pinctrl: aspeed: Enable ASPEED pinctrl driver to modify SPI1 strap
    bits

 drivers/pinctrl/aspeed/pinctrl-aspeed.c | 22 ++++++++++++++++++++--
 drivers/pinctrl/aspeed/pinctrl-aspeed.h |  2 +-
 2 files changed, 21 insertions(+), 3 deletions(-)

-- 
2.8.0.rc3.226.g39d4020