soc: imx: gpc: Disable 6sl display power gating for ERR006287

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 <leonard.crestez@nxp.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
index 32f0748..13ff983 100644 (file)
--- a/drivers/soc/imx/gpc.c
+++ b/drivers/soc/imx/gpc.c
@@ -288,26 +288,31 @@ 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[] = {
@@ -416,6 +421,11 @@ static int imx_gpc_probe(struct platform_device *pdev)
                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);