From: Marek Vasut marex@denx.de
[ Upstream commit df88005bd81b80c944d185554e264a4b0f993c37 ]
In case the power domain clock are ungated before the reset is asserted, the system might freeze completely. This is likely due to a device is an undefined state being attached to bus, which sporadically leads to a bus hang. Assert the reset before the clock are enabled to assure the device is in defined state before being attached to bus.
Fixes: fe58c887fb8ca ("soc: imx: gpcv2: add support for optional resets") Signed-off-by: Marek Vasut marex@denx.de Reviewed-by: Fabio Estevam festevam@denx.de Reviewed-by: Lucas Stach l.stach@pengutronix.de Signed-off-by: Shawn Guo shawnguo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/soc/imx/gpcv2.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c index b4aa28420f2a8..4dc3a3f73511e 100644 --- a/drivers/soc/imx/gpcv2.c +++ b/drivers/soc/imx/gpcv2.c @@ -237,6 +237,8 @@ static int imx_pgc_power_up(struct generic_pm_domain *genpd) } }
+ reset_control_assert(domain->reset); + /* Enable reset clocks for all devices in the domain */ ret = clk_bulk_prepare_enable(domain->num_clks, domain->clks); if (ret) { @@ -244,7 +246,8 @@ static int imx_pgc_power_up(struct generic_pm_domain *genpd) goto out_regulator_disable; }
- reset_control_assert(domain->reset); + /* delays for reset to propagate */ + udelay(5);
if (domain->bits.pxx) { /* request the domain to power up */