[PATCH v2] pci: pci_mvebu: Add support for reset-gpios

[Pali Rohár]

Release PERST# signal via GPIO when "reset-gpios" is defined in device tree.

Signed-off-by: Pali Rohár <pali at kernel.org>
Reviewed-by: Stefan Roese <sr at denx.de>
---
Changes in v2:
* select DM_GPIO
* use asm/gpio.h
---
 drivers/pci/Kconfig     |  1 +
 drivers/pci/pci_mvebu.c | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 436acca898e4..22f4995453ed 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -301,6 +301,7 @@ config PCI_MVEBU
 	depends on (ARCH_KIRKWOOD || ARCH_MVEBU)
 	select MISC
 	select DM_RESET
+	select DM_GPIO
 	help
 	  Say Y here if you want to enable PCIe controller support on
 	  Kirkwood and Armada 370/XP/375/38x SoCs.
diff --git a/drivers/pci/pci_mvebu.c b/drivers/pci/pci_mvebu.c
index d80f87e0cfc6..5bd340a421b8 100644
--- a/drivers/pci/pci_mvebu.c
+++ b/drivers/pci/pci_mvebu.c
@@ -22,6 +22,7 @@
 #include <asm/io.h>
 #include <asm/arch/cpu.h>
 #include <asm/arch/soc.h>
+#include <asm/gpio.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
@@ -60,6 +61,7 @@ struct mvebu_pcie {
 	struct resource mem;
 	void __iomem *iobase;
 	struct resource io;
+	struct gpio_desc reset_gpio;
 	u32 intregs;
 	u32 port;
 	u32 lane;
@@ -416,6 +418,14 @@ static int mvebu_pcie_probe(struct udevice *dev)
 	struct udevice *ctlr = pci_get_controller(dev);
 	struct pci_controller *hose = dev_get_uclass_priv(ctlr);
 	u32 reg;
+	int ret;
+
+	/* Request for optional PERST# GPIO */
+	ret = gpio_request_by_name(dev, "reset-gpios", 0, &pcie->reset_gpio, GPIOD_IS_OUT);
+	if (ret && ret != -ENOENT) {
+		printf("%s: unable to request reset-gpios: %d\n", pcie->name, ret);
+		return ret;
+	}
 
 	/*
 	 * Change Class Code of PCI Bridge device to PCI Bridge (0x600400)
@@ -537,6 +547,10 @@ static int mvebu_pcie_probe(struct udevice *dev)
 	pcie->cfgcache[(PCI_PREF_MEMORY_BASE - 0x10) / 4] =
 		PCI_PREF_RANGE_TYPE_64 | (PCI_PREF_RANGE_TYPE_64 << 16);
 
+	/* Release PERST# via GPIO when it was defined */
+	if (dm_gpio_is_valid(&pcie->reset_gpio))
+		dm_gpio_set_value(&pcie->reset_gpio, 0);
+
 	mvebu_pcie_wait_for_link(pcie);
 
 	return 0;
-- 
2.20.1