Hi Lucas, > -----Original Message----- > From: Lucas Stach [mailto:l.stach@xxxxxxxxxxxxxx] > Sent: Thursday, March 23, 2017 10:44 PM > To: Shawn Guo > Cc: Fabio Estevam; A.S. Dong; devicetree@xxxxxxxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; patchwork- > lst@xxxxxxxxxxxxxx > Subject: [PATCH 2/2] soc/imx: add workaround for i.MX6QP to the GPC PD > driver > > On i.MX6QP, due to hardware erratum ERR009619, the PRE clocks may be > stalled during the power up sequencing of the PU power domain. As this may > lead to a complete loss of display output, the recommended workaround is > to keep the PU domain enabled during normal system operation. > > Implement this by rejecting the domain power down request on the affected > SoC. > > Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > --- > drivers/soc/imx/gpc.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c index > 4294287e5f6c..599e1e46f694 100644 > --- a/drivers/soc/imx/gpc.c > +++ b/drivers/soc/imx/gpc.c > @@ -45,6 +45,7 @@ struct imx_pm_domain { > unsigned int reg_offs; > signed char cntr_pdn_bit; > unsigned int ipg_rate_mhz; > + bool allow_dynamic_pd; > }; > > static inline struct imx_pm_domain * > @@ -59,6 +60,9 @@ static int imx6_pm_domain_power_off(struct > generic_pm_domain *genpd) > int iso, iso2sw; > u32 val; > > + if (!pd->allow_dynamic_pd) > + return -EBUSY; > + > /* Read ISO and ISO2SW power down delays */ > regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PUPSCR_OFFS, &val); > iso = val & 0x3f; > @@ -255,6 +259,7 @@ static struct imx_pm_domain imx_gpc_domains[] = { > }, > .reg_offs = 0x260, > .cntr_pdn_bit = 0, > + .allow_dynamic_pd = true, > }, { > .base = { > .name = "DISPLAY", > @@ -263,23 +268,33 @@ static struct imx_pm_domain imx_gpc_domains[] = { > }, > .reg_offs = 0x240, > .cntr_pdn_bit = 4, > + .allow_dynamic_pd = true, Just a Nitpick, besides shawn's comment in another mail, if we use a domain flag like IMX_PD_ALWAYS_ON set by SoC errata flag, then probably we can save all the default allow_dynamic_pd lines. This also release the life when adding new domains. Otherwise, the two patch seems good to me. Regards Dong Aisheng > } > }; > > struct imx_gpc_dt_data { > int num_domains; > + bool err009619_present; > }; > > static const struct imx_gpc_dt_data imx6q_dt_data = { > .num_domains = 2, > + .err009619_present = false, > +}; > + > +static const struct imx_gpc_dt_data imx6qp_dt_data = { > + .num_domains = 2, > + .err009619_present = true, > }; > > static const struct imx_gpc_dt_data imx6sl_dt_data = { > .num_domains = 3, > + .err009619_present = false, > }; > > static const struct of_device_id imx_gpc_dt_ids[] = { > { .compatible = "fsl,imx6q-gpc", .data = &imx6q_dt_data }, > + { .compatible = "fsl,imx6qp-gpc", .data = &imx6qp_dt_data }, > { .compatible = "fsl,imx6sl-gpc", .data = &imx6sl_dt_data }, > { } > }; > @@ -377,6 +392,10 @@ static int imx_gpc_probe(struct platform_device *pdev) > return ret; > } > > + /* Disable PU power down in normal operation if ERR009619 is present > */ > + if (of_id_data->err009619_present) > + imx_gpc_domains[1].allow_dynamic_pd = false; > + > if (!pgc_node) { > ret = imx_gpc_old_dt_init(&pdev->dev, regmap, > of_id_data->num_domains); > -- > 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
