Hi Vince, On 10/08/16 06:23, Vince Hsu wrote: > Reading the DPD_REQ & DPD2_REQ registers returns the previous requests. > If we sets the current request bit with the returned value, then other > pads will be turned on or off unexpectedly. It was not 100% clear to me at first, but now I do see what you mean. The IO_DPD_REQ_CODE_OFF/ON indicates whether the rails are being turned off or on and then this action is applied for all rails whose bit is set. I have also taken a look at the Tegra TRMs for Tegra30, Tegra124 and Tegra210 and this behaviour appears consistent across all devices. > Signed-off-by: Vince Hsu <vinceh@xxxxxxxxxx> > --- > Hi, > > I found this issue when debugging one HDMI issue which only happened > after LP0 on Tegra124 chromebook. I did not test this patch on any > upstream platforms due to lack of setup, but it did pass Nvidia > internal EMIT verification. > > Thanks, > Vince > > > drivers/soc/tegra/pmc.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c > index 71c834f3847e..43c01a85334c 100644 > --- a/drivers/soc/tegra/pmc.c > +++ b/drivers/soc/tegra/pmc.c > @@ -979,8 +979,7 @@ int tegra_io_rail_power_on(unsigned int id) > > mask = 1 << bit; > > - value = tegra_pmc_readl(request); > - value |= mask; > + value = mask; > value &= ~IO_DPD_REQ_CODE_MASK; > value |= IO_DPD_REQ_CODE_OFF; Nit ... can we simply this further to be just ... value = IO_DPD_REQ_CODE_OFF | BIT(bit); > tegra_pmc_writel(value, request); > @@ -1016,8 +1015,7 @@ int tegra_io_rail_power_off(unsigned int id) > > mask = 1 << bit; > > - value = tegra_pmc_readl(request); > - value |= mask; > + value = mask; > value &= ~IO_DPD_REQ_CODE_MASK; > value |= IO_DPD_REQ_CODE_ON; Same here? > tegra_pmc_writel(value, request); > Otherwise ... Reviewed-by: Jon Hunter <jonathanh@xxxxxxxxxx> Cheers Jon -- nvpublic -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
