Hi Damian, On Mon, May 9, 2011 at 4:03 PM, Damian Hobson-Garcia <dhobsong@xxxxxxxxxx> wrote: > Hi Magnus, > >> Please add Runtime PM support to the MERAM driver. The MSTP113 bit of >> SMSTPCR1 should be dynamically controlled using pm_runtime_get_sync() >> and pm_runtime_put_sync(). > > So one thing that I noticed while adding in the runtime PM support is > that the MERAM bit in RMSTPCR1 seems to be enabled as a power on default > on the chip. (I determined this by dumping the register from u-boot and > poking around in the u-boot code to verify that u-boot doesn't seem to > be enabling this). > > Even if pm_runtime_get_sync() and pm_runtime_put_sync() correctly enable > and disable the SMSTPCR1, with the RMSTPCR1 enabled, the clock doesn't > actually turn off. > > While I still think that its a good idea to add the > pm_runtime_get_sync() and pm_runtime_put_sync() calls to do their thing > on the SMSTPCR1 side, with the current configuration we won't actually > be saving any power. Good catch, yes, the MSTP bits need to be disabled on both sides for the clocks to be stopped. I recall the default state of each MSTP bit to vary somehow. I think we simply should add code to initialize all SH-side MSTP bits as disabled, that's the easiest. Thanks, / magnus -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
