From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lucas Stach Subject: Re: [PATCH v3 1/2] soc: imx: gpc: Disable 6sl display power gating for ERR006287 Date: Wed, 11 Jul 2018 14:16:32 +0200 Message-ID: <1531311392.3163.47.camel@pengutronix.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Leonard Crestez , Ulf Hansson , Shawn Guo Cc: Fabio Estevam , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-imx@nxp.com, kernel@pengutronix.de List-Id: linux-pm@vger.kernel.org Am Mittwoch, den 11.07.2018, 15:11 +0300 schrieb Leonard Crestez: > The imx6sl chip errata document describes ERR006287 like this: > > > Upon resuming from power gating, the modules in the display power domain > > (eLCDIF, EPDC, PXP and SPDC) might fail to perform register reads > correctly. > > > When the modules listed above are used, do not use power gating on the > > display power domain. > > Link: https://www.nxp.com/docs/en/errata/IMX6SLCE.pdf#page=62 > > Handle this in the safest possible way by keeping the DISP domain > always-on. > > Signed-off-by: Leonard Crestez Reviewed-by: Lucas Stach Can you send a follow on patch to switch the i.MX6QP errata workaround to use GENPD_FLAG_ALWAYS_ON and remove the -EBUSY stuff in the power down path? Regards, Lucas > --- >  drivers/soc/imx/gpc.c | 10 ++++++++++ >  1 file changed, 10 insertions(+) > > diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c > index 526f2d02dc78..f7960f773019 100644 > --- a/drivers/soc/imx/gpc.c > +++ b/drivers/soc/imx/gpc.c > @@ -339,30 +339,35 @@ static struct imx_pm_domain imx_gpc_domains[] = { >  }; >   >  struct imx_gpc_dt_data { > >   int num_domains; > >   bool err009619_present; > > + bool err006287_present; >  }; >   >  static const struct imx_gpc_dt_data imx6q_dt_data = { > >   .num_domains = 2, > >   .err009619_present = false, > > + .err006287_present = false, >  }; >   >  static const struct imx_gpc_dt_data imx6qp_dt_data = { > >   .num_domains = 2, > >   .err009619_present = true, > > + .err006287_present = false, >  }; >   >  static const struct imx_gpc_dt_data imx6sl_dt_data = { > >   .num_domains = 3, > >   .err009619_present = false, > > + .err006287_present = true, >  }; >   >  static const struct imx_gpc_dt_data imx6sx_dt_data = { > >   .num_domains = 4, > >   .err009619_present = false, > > + .err006287_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 }, > @@ -467,10 +472,15 @@ static int imx_gpc_probe(struct platform_device *pdev) > >   /* Disable PU power down in normal operation if ERR009619 is present */ > >   if (of_id_data->err009619_present) > >   imx_gpc_domains[GPC_PGC_DOMAIN_PU].flags |= > >   PGC_DOMAIN_FLAG_NO_PD; >   > > + /* Keep DISP always on if ERR006287 is present */ > > + if (of_id_data->err006287_present) > > + imx_gpc_domains[GPC_PGC_DOMAIN_DISPLAY].base.flags |= > > + GENPD_FLAG_ALWAYS_ON; > + > >   if (!pgc_node) { > >   ret = imx_gpc_old_dt_init(&pdev->dev, regmap, > >     of_id_data->num_domains); > >   if (ret) > >   return ret;