[PATCH v2 2/2] PCI: imx6: Add reset-gpio-active-high boolean property to DT

[Petr Štetiar]

We need that property in order to make the Toradex Apalis SoMs working
without breaking old DTBs. On Apalis SoMs the GPIO1_IO28 used to PCIe
reset is not connected directly to PERST# PCIe signal, but it's ORed
with RESETBMCU coming off the PMIC, and thus is inverted, active-high.

Signed-off-by: Petr Štetiar <ynezz at true.cz>
---
 Changes since v1:
  
  * Added documentation of reset-gpio and reset-gpio-active-high DT properties
  * Removed unnecessary double negation of GPIO value

 Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt |  5 +++++
 drivers/pci/host/pci-imx6.c                              | 14 +++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
index 3be80c6..23ecb47 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
@@ -19,6 +19,11 @@ Optional properties:
 - fsl,tx-deemph-gen2-6db: Gen2 (6db) De-emphasis value. Default: 20
 - fsl,tx-swing-full: Gen2 TX SWING FULL value. Default: 127
 - fsl,tx-swing-low: TX launch amplitude swing_low value. Default: 127
+- reset-gpio: Should specify the GPIO for PHY reset. Its not polarity aware
+  and defaults to active-low reset sequence (L=reset state, H=operation state).
+- reset-gpio-active-high: If present then the reset sequence using the GPIO
+  specified in the "reset-gpio" property is reversed (H=reset state,
+  L=operation state).
 
 Example:
 
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 2f817fa..17f4cc3 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -33,6 +33,7 @@
 
 struct imx6_pcie {
 	int			reset_gpio;
+	bool			gpio_active_high;
 	struct clk		*pcie_bus;
 	struct clk		*pcie_phy;
 	struct clk		*pcie;
@@ -310,9 +311,11 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
 
 	/* Some boards don't have PCIe reset GPIO. */
 	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
-		gpio_set_value_cansleep(imx6_pcie->reset_gpio, 0);
+		gpio_set_value_cansleep(imx6_pcie->reset_gpio,
+					imx6_pcie->gpio_active_high);
 		msleep(100);
-		gpio_set_value_cansleep(imx6_pcie->reset_gpio, 1);
+		gpio_set_value_cansleep(imx6_pcie->reset_gpio,
+					!imx6_pcie->gpio_active_high);
 	}
 	return 0;
 
@@ -546,9 +549,14 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
 
 	/* Fetch GPIOs */
 	imx6_pcie->reset_gpio = of_get_named_gpio(np, "reset-gpio", 0);
+	imx6_pcie->gpio_active_high = of_property_read_bool(np,
+						"reset-gpio-active-high");
 	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
 		ret = devm_gpio_request_one(&pdev->dev, imx6_pcie->reset_gpio,
-					    GPIOF_OUT_INIT_LOW, "PCIe reset");
+				imx6_pcie->gpio_active_high ?
+					GPIOF_OUT_INIT_HIGH :
+					GPIOF_OUT_INIT_LOW,
+				"PCIe reset");
 		if (ret) {
 			dev_err(&pdev->dev, "unable to get reset gpio\n");
 			return ret;
-- 
1.9.1