soc: imx: gpcv2: allow domains without power-sequence control

Some of the PGC domains only control the handshake with the ADB400
and don't have any power sequence controls. Make such domains work
by allowing the pxx and map bits to be empty and skip all actions
using those controls.
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

drivers/soc/imx/gpcv2.c

@@ -163,24 +163,27 @@ static int imx_pgc_power_up(struct generic_pm_domain *genpd)
 		goto out_regulator_disable;
 	}
 
-	/* request the domain to power up */
-	regmap_update_bits(domain->regmap, GPC_PU_PGC_SW_PUP_REQ,
-			   domain->bits.pxx, domain->bits.pxx);
-	/*
-	 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
-	 * for PUP_REQ/PDN_REQ bit 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 (ret) {
-		dev_err(domain->dev, "failed to command PGC\n");
-		goto out_clk_disable;
-	}
+	if (domain->bits.pxx) {
+		/* request the domain to power up */
+		regmap_update_bits(domain->regmap, GPC_PU_PGC_SW_PUP_REQ,
+				   domain->bits.pxx, domain->bits.pxx);
+		/*
+		 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
+		 * for PUP_REQ/PDN_REQ bit 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 (ret) {
+			dev_err(domain->dev, "failed to command PGC\n");
+			goto out_clk_disable;
+		}
 
-	/* disable power control */
-	regmap_clear_bits(domain->regmap, GPC_PGC_CTRL(domain->pgc),
-			  GPC_PGC_CTRL_PCR);
+		/* disable power control */
+		regmap_clear_bits(domain->regmap, GPC_PGC_CTRL(domain->pgc),
+				  GPC_PGC_CTRL_PCR);
+	}
 
 	/* request the ADB400 to power up */
 	if (domain->bits.hskreq) {
@@ -245,23 +248,26 @@ static int imx_pgc_power_down(struct generic_pm_domain *genpd)
 		}
 	}
 
-	/* enable power control */
-	regmap_update_bits(domain->regmap, GPC_PGC_CTRL(domain->pgc),
-			   GPC_PGC_CTRL_PCR, GPC_PGC_CTRL_PCR);
-
-	/* request the domain to power down */
-	regmap_update_bits(domain->regmap, GPC_PU_PGC_SW_PDN_REQ,
-			   domain->bits.pxx, domain->bits.pxx);
-	/*
-	 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
-	 * for PUP_REQ/PDN_REQ bit to be cleared
-	 */
-	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;
+	if (domain->bits.pxx) {
+		/* enable power control */
+		regmap_update_bits(domain->regmap, GPC_PGC_CTRL(domain->pgc),
+				   GPC_PGC_CTRL_PCR, GPC_PGC_CTRL_PCR);
+
+		/* request the domain to power down */
+		regmap_update_bits(domain->regmap, GPC_PU_PGC_SW_PDN_REQ,
+				   domain->bits.pxx, domain->bits.pxx);
+		/*
+		 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
+		 * for PUP_REQ/PDN_REQ bit to be cleared
+		 */
+		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;
+		}
 	}
 
 	/* Disable reset clocks for all devices in the domain */
@@ -536,8 +542,9 @@ static int imx_pgc_domain_probe(struct platform_device *pdev)
 
 	pm_runtime_enable(domain->dev);
 
-	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
-			   domain->bits.map, domain->bits.map);
+	if (domain->bits.map)
+		regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+				   domain->bits.map, domain->bits.map);
 
 	ret = pm_genpd_init(&domain->genpd, NULL, true);
 	if (ret) {
@@ -557,8 +564,9 @@ static int imx_pgc_domain_probe(struct platform_device *pdev)
 out_genpd_remove:
 	pm_genpd_remove(&domain->genpd);
 out_domain_unmap:
-	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
-			   domain->bits.map, 0);
+	if (domain->bits.map)
+		regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+				   domain->bits.map, 0);
 	pm_runtime_disable(domain->dev);
 
 	return ret;
@@ -571,8 +579,9 @@ static int imx_pgc_domain_remove(struct platform_device *pdev)
 	of_genpd_del_provider(domain->dev->of_node);
 	pm_genpd_remove(&domain->genpd);
 
-	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
-			   domain->bits.map, 0);
+	if (domain->bits.map)
+		regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+				   domain->bits.map, 0);
 
 	pm_runtime_disable(domain->dev);