[PATCH v7 03/16] PCI: imx6: Simplify reset handling by using by using *_FLAG_HAS_*_RESET

[Frank Li <Frank.Li@nxp.com>]

Refactors the reset handling logic in the imx6 PCI driver by adding
IMX6_PCIE_FLAG_HAS_*_RESET bitmask define for drvdata::flags.

The drvdata::flags and a bitmask ensures a cleaner and more scalable
switch-case structure for handling reset.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---

Notes:
    Change from v4 to v5:
    - Add Mani's Reviewed-by tag
    - Fixed MQ_EP's flags
    
    Chagne from v3 to v4:
    - none
    Change from v2 to v3:
    - add Philipp's Reviewed-by tag
    Change from v1 to v2:
    - remove condition check before reset_control_(de)assert() because it is
      none ops if a NULL pointer pass down.
    - still keep condition check at probe to help identify dts file mismatch
      problem.
    
    Change from v1 to v2:
    - remove condition check before reset_control_(de)assert() because it is
      none ops if a NULL pointer pass down.
    - still keep condition check at probe to help identify dts file mismatch
      problem.

 drivers/pci/controller/dwc/pci-imx6.c | 108 ++++++++++----------------
 1 file changed, 41 insertions(+), 67 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 4d620249f3d52..294f61a9c6fd9 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -61,6 +61,8 @@ enum imx6_pcie_variants {
 #define IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE	BIT(1)
 #define IMX6_PCIE_FLAG_SUPPORTS_SUSPEND		BIT(2)
 #define IMX6_PCIE_FLAG_HAS_PHY			BIT(3)
+#define IMX6_PCIE_FLAG_HAS_APP_RESET		BIT(4)
+#define IMX6_PCIE_FLAG_HAS_PHY_RESET		BIT(5)
 
 #define imx6_check_flag(pci, val)     (pci->drvdata->flags & val)
 
@@ -661,18 +663,10 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
 
 static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 {
+	reset_control_assert(imx6_pcie->pciephy_reset);
+	reset_control_assert(imx6_pcie->apps_reset);
+
 	switch (imx6_pcie->drvdata->variant) {
-	case IMX7D:
-	case IMX8MQ:
-	case IMX8MQ_EP:
-		reset_control_assert(imx6_pcie->pciephy_reset);
-		fallthrough;
-	case IMX8MM:
-	case IMX8MM_EP:
-	case IMX8MP:
-	case IMX8MP_EP:
-		reset_control_assert(imx6_pcie->apps_reset);
-		break;
 	case IMX6SX:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
 				   IMX6SX_GPR12_PCIE_TEST_POWERDOWN,
@@ -693,6 +687,8 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
 				   IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
 		break;
+	default:
+		break;
 	}
 
 	/* Some boards don't have PCIe reset GPIO. */
@@ -706,14 +702,10 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	struct dw_pcie *pci = imx6_pcie->pci;
 	struct device *dev = pci->dev;
 
+	reset_control_deassert(imx6_pcie->pciephy_reset);
+
 	switch (imx6_pcie->drvdata->variant) {
-	case IMX8MQ:
-	case IMX8MQ_EP:
-		reset_control_deassert(imx6_pcie->pciephy_reset);
-		break;
 	case IMX7D:
-		reset_control_deassert(imx6_pcie->pciephy_reset);
-
 		/* Workaround for ERR010728, failure of PCI-e PLL VCO to
 		 * oscillate, especially when cold.  This turns off "Duty-cycle
 		 * Corrector" and other mysterious undocumented things.
@@ -745,11 +737,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 
 		usleep_range(200, 500);
 		break;
-	case IMX6Q:		/* Nothing to do */
-	case IMX8MM:
-	case IMX8MM_EP:
-	case IMX8MP:
-	case IMX8MP_EP:
+	default:
 		break;
 	}
 
@@ -796,16 +784,11 @@ static void imx6_pcie_ltssm_enable(struct device *dev)
 				   IMX6Q_GPR12_PCIE_CTL_2,
 				   IMX6Q_GPR12_PCIE_CTL_2);
 		break;
-	case IMX7D:
-	case IMX8MQ:
-	case IMX8MQ_EP:
-	case IMX8MM:
-	case IMX8MM_EP:
-	case IMX8MP:
-	case IMX8MP_EP:
-		reset_control_deassert(imx6_pcie->apps_reset);
+	default:
 		break;
 	}
+
+	reset_control_deassert(imx6_pcie->apps_reset);
 }
 
 static void imx6_pcie_ltssm_disable(struct device *dev)
@@ -819,16 +802,11 @@ static void imx6_pcie_ltssm_disable(struct device *dev)
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
 				   IMX6Q_GPR12_PCIE_CTL_2, 0);
 		break;
-	case IMX7D:
-	case IMX8MQ:
-	case IMX8MQ_EP:
-	case IMX8MM:
-	case IMX8MM_EP:
-	case IMX8MP:
-	case IMX8MP_EP:
-		reset_control_assert(imx6_pcie->apps_reset);
+	default:
 		break;
 	}
+
+	reset_control_assert(imx6_pcie->apps_reset);
 }
 
 static int imx6_pcie_start_link(struct dw_pcie *pci)
@@ -1287,36 +1265,24 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 					     "failed to get pcie phy\n");
 	}
 
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX7D:
-		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
-			imx6_pcie->controller_id = 1;
-
-		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev,
-									    "pciephy");
-		if (IS_ERR(imx6_pcie->pciephy_reset)) {
-			dev_err(dev, "Failed to get PCIEPHY reset control\n");
-			return PTR_ERR(imx6_pcie->pciephy_reset);
-		}
-
-		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
-									 "apps");
-		if (IS_ERR(imx6_pcie->apps_reset)) {
-			dev_err(dev, "Failed to get PCIE APPS reset control\n");
-			return PTR_ERR(imx6_pcie->apps_reset);
-		}
-		break;
-	case IMX8MM:
-	case IMX8MM_EP:
-	case IMX8MP:
-	case IMX8MP_EP:
-		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
-									 "apps");
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_APP_RESET)) {
+		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev, "apps");
 		if (IS_ERR(imx6_pcie->apps_reset))
 			return dev_err_probe(dev, PTR_ERR(imx6_pcie->apps_reset),
 					     "failed to get pcie apps reset control\n");
+	}
 
-		break;
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_PHY_RESET)) {
+		imx6_pcie->pciephy_reset = devm_reset_control_get_exclusive(dev, "pciephy");
+		if (IS_ERR(imx6_pcie->pciephy_reset))
+			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pciephy_reset),
+					     "Failed to get PCIEPHY reset control\n");
+	}
+
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX7D:
+		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
+			imx6_pcie->controller_id = 1;
 	default:
 		break;
 	}
@@ -1438,31 +1404,39 @@ static const struct imx6_pcie_drvdata drvdata[] = {
 	},
 	[IMX7D] = {
 		.variant = IMX7D,
-		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
+		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
+			 IMX6_PCIE_FLAG_HAS_APP_RESET |
+			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
 		.gpr = "fsl,imx7d-iomuxc-gpr",
 		.clk_names = {"pcie_bus", "pcie", "pcie_phy"},
 	},
 	[IMX8MQ] = {
 		.variant = IMX8MQ,
+		.flags = IMX6_PCIE_FLAG_HAS_APP_RESET |
+			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
 		.gpr = "fsl,imx8mq-iomuxc-gpr",
 		.clk_names = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"},
 	},
 	[IMX8MM] = {
 		.variant = IMX8MM,
 		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
-			 IMX6_PCIE_FLAG_HAS_PHY,
+			 IMX6_PCIE_FLAG_HAS_PHY |
+			 IMX6_PCIE_FLAG_HAS_APP_RESET,
 		.gpr = "fsl,imx8mm-iomuxc-gpr",
 		.clk_names = {"pcie_bus", "pcie", "pcie_aux"},
 	},
 	[IMX8MP] = {
 		.variant = IMX8MP,
 		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
-			 IMX6_PCIE_FLAG_HAS_PHY,
+			 IMX6_PCIE_FLAG_HAS_PHY |
+			 IMX6_PCIE_FLAG_HAS_APP_RESET,
 		.gpr = "fsl,imx8mp-iomuxc-gpr",
 		.clk_names = {"pcie_bus", "pcie", "pcie_aux"},
 	},
 	[IMX8MQ_EP] = {
 		.variant = IMX8MQ_EP,
+		.flags = IMX6_PCIE_FLAG_HAS_APP_RESET |
+			 IMX6_PCIE_FLAG_HAS_PHY_RESET,
 		.mode = DW_PCIE_EP_TYPE,
 		.gpr = "fsl,imx8mq-iomuxc-gpr",
 		.clk_names = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"},
-- 
2.34.1