Messages in this thread | | | From | Stephen Warren <> | Date | Mon, 14 Nov 2011 11:00:45 -0800 | Subject | RE: [PATCH] ARM: SAMSUNG: Save/restore GPIO drive strength across suspend/resume |
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Thomas Abraham wrote at Monday, November 14, 2011 6:57 AM: > On 12 November 2011 16:30, Linus Walleij <linus.walleij@linaro.org> wrote: > > On Sat, Nov 12, 2011 at 6:01 AM, Inderpal Singh > > <inderpal.singh@linaro.org> wrote: > > > >> GPIO driver strength settings are not preserved across suspend/resume > >> for s5pc100, s5pv210 and Exynos platforms which has been the cause of > >> mmc/sd card read/write failures after resume. Fix this by saving and > >> restoring the GPIO driver strength register settings across suspend/resume. > >> > >> Signed-off-by: Inderpal Singh <inderpal.singh@linaro.org> > > > > On a related theme: I am thinking about how to support preserving > > drive strength (etc) across suspend/resume and deepsleep in the > > pincontrol subsystem. > > > > Currently I am playing with the idea to let pin groups have states, > > as the different configurations seem to be 90% or so about very > > specific sleep modes, so say: > > > > pinconf_set_group_state("mmcgroup", PINCONF_STATE_ACTIVE); > > pinconf_set_group_state("mmcgroup", PINCONF_STATE_SUSPENDED); > > pinconf_set_group_state("mmcgroup", PINCONF_STATE_SLEEP); > > > The API name suggests that power state is set based on a pin group. > For a driver, the following could be convenient as the driver transits > through various power management states. > > struct pinmux pmx; > pmx = pinmux_get(dev, "i2c0"); > > [...] > > pinmux_set_state(pmx, PINCONF_STATE_SLEEP); > [...] > pinmux_set_state(pmx, PINCONF_STATE_ACTIVE);
That seems a more consistent driver-oriented API, yes.
I'd of course lean towards adding the pin config data into the mapping table, and using the existing feature struct pinmux_map name field to name those states, and allowing dynamic transitioning between states, rather than adding a complete new API and namespace for these states.
-- nvpublic
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