linux-kernel - [PATCH v1 1/4] soc: imx8mm: gpcv2: Power sequence for DISP

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Date:   Mon,  2 May 2022 12:02:30 +0200
From:   Viraj Shah <viraj.shah@...utronix.de>
To:     shawnguo@...nel.org, s.hauer@...gutronix.de
Cc:     Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Peng Fan <peng.fan@....com>,
        Frieder Schrempf <frieder.schrempf@...tron.de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/4] soc: imx8mm: gpcv2: Power sequence for DISP

As per the imx8mm reference manual, read bit 25(GPC_DISPMIX_
PWRDNACKN) of the power handshake register and wait for ack during
power on/off.

Signed-off-by: Viraj Shah <viraj.shah@...utronix.de>
---
 drivers/soc/imx/gpcv2.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
index 3cb123016b3e..8ee70c30964f 100644
--- a/drivers/soc/imx/gpcv2.c
+++ b/drivers/soc/imx/gpcv2.c
@@ -254,11 +254,24 @@ static int imx_pgc_power_up(struct generic_pm_domain *genpd)
 		/*
 		 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
 		 * for PUP_REQ/PDN_REQ bit to be cleared
+		 *
+		 * As per "5.2.9.5 Example Code 5" in i.MX-8MMini-yhsc.pdf
+		 * Display power on section checks for bit 25 of
+		 * Power handshake register to be cleared.
 		 */
-		ret = regmap_read_poll_timeout(domain->regmap,
-					       GPC_PU_PGC_SW_PUP_REQ, reg_val,
-					       !(reg_val & domain->bits.pxx),
-					       0, USEC_PER_MSEC);
+		if (domain->bits.pxx == IMX8MM_DISPMIX_SW_Pxx_REQ) {
+			regmap_update_bits(domain->regmap, GPC_PU_PWRHSK,
+				   BIT(7), BIT(7));
+			ret = regmap_read_poll_timeout(domain->regmap,
+						GPC_PU_PWRHSK, reg_val,
+						!(reg_val & IMX8MM_DISPMIX_HSK_PWRDNACKN),
+						0, USEC_PER_MSEC);
+		} else
+			ret = regmap_read_poll_timeout(domain->regmap,
+						GPC_PU_PGC_SW_PUP_REQ, reg_val,
+						!(reg_val & domain->bits.pxx),
+						0, USEC_PER_MSEC);
+
 		if (ret) {
 			dev_err(domain->dev, "failed to command PGC\n");
 			goto out_clk_disable;
@@ -355,11 +368,24 @@ static int imx_pgc_power_down(struct generic_pm_domain *genpd)
 		/*
 		 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
 		 * for PUP_REQ/PDN_REQ bit to be cleared
+		 *
+		 * As per "5.2.9.5 Example Code 5" in i.MX-8MMini-yhsc.pdf
+		 * Display power on section checks for bit 25 of
+		 * Power handshake register to be set.
 		 */
-		ret = regmap_read_poll_timeout(domain->regmap,
+		if (domain->bits.pxx == IMX8MM_DISPMIX_SW_Pxx_REQ) {
+			regmap_clear_bits(domain->regmap, GPC_PU_PWRHSK,
+				   BIT(7));
+			ret = regmap_read_poll_timeout(domain->regmap,
+						GPC_PU_PWRHSK, reg_val,
+						!(reg_val & IMX8MM_DISPMIX_HSK_PWRDNACKN),
+						0, USEC_PER_MSEC);
+		} else {
+			ret = regmap_read_poll_timeout(domain->regmap,
 					       GPC_PU_PGC_SW_PDN_REQ, reg_val,
 					       !(reg_val & domain->bits.pxx),
 					       0, USEC_PER_MSEC);
+		}
 		if (ret) {
 			dev_err(domain->dev, "failed to command PGC\n");
 			goto out_clk_disable;
-- 
2.20.1