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Commit 52ba992e authored by Sebastian Hesselbarth's avatar Sebastian Hesselbarth Committed by Jason Cooper
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PCI: mvebu: add support for reset on GPIO 



This patch adds a check for DT passed reset-gpios property and deasserts/
asserts reset pin on probe/remove with configurable delay. Corresponding
binding documentation is also updated.

Signed-off-by: default avatarSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: default avatarJason Cooper <jason@lakedaemon.net>
parent e5615c30

Documentation/devicetree/bindings/pci/mvebu-pci.txt

+6 −0
Original line number Diff line number Diff line
@@ -76,6 +76,8 @@ and the following optional properties: 
- marvell,pcie-lane: the physical PCIe lane number, for ports having

  multiple lanes. If this property is not found, we assume that the

  value is 0.

- reset-gpios: optional gpio to PERST#

- reset-delay-us: delay in us to wait after reset de-assertion



Example:
@@ -138,6 +140,10 @@ pcie-controller { 
		interrupt-map = <0 0 0 0 &mpic 58>;

		marvell,pcie-port = <0>;

		marvell,pcie-lane = <0>;

		/* low-active PERST# reset on GPIO 25 */

		reset-gpios = <&gpio0 25 1>;

		/* wait 20ms for device settle after reset deassertion */

		reset-delay-us = <20000>;

		clocks = <&gateclk 5>;

		status = "disabled";

	};

drivers/pci/host/pci-mvebu.c

+32 −1
Original line number Diff line number Diff line
@@ -9,14 +9,17 @@ 
#include <linux/kernel.h>

#include <linux/pci.h>

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/gpio.h>

#include <linux/module.h>

#include <linux/mbus.h>

#include <linux/msi.h>

#include <linux/slab.h>

#include <linux/platform_device.h>

#include <linux/of_address.h>

#include <linux/of_pci.h>

#include <linux/of_irq.h>

#include <linux/of_gpio.h>

#include <linux/of_pci.h>

#include <linux/of_platform.h>



/*
@@ -126,6 +129,9 @@ struct mvebu_pcie_port { 
	unsigned int io_target;

	unsigned int io_attr;

	struct clk *clk;

	int reset_gpio;

	int reset_active_low;

	char *reset_name;

	struct mvebu_sw_pci_bridge bridge;

	struct device_node *dn;

	struct mvebu_pcie *pcie;
@@ -857,6 +863,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev) 
	i = 0;

	for_each_child_of_node(pdev->dev.of_node, child) {

		struct mvebu_pcie_port *port = &pcie->ports[i];

		enum of_gpio_flags flags;



		if (!of_device_is_available(child))

			continue;
@@ -897,6 +904,30 @@ static int mvebu_pcie_probe(struct platform_device *pdev) 
			continue;

		}



		port->reset_gpio = of_get_named_gpio_flags(child,

						   "reset-gpios", 0, &flags);

		if (gpio_is_valid(port->reset_gpio)) {

			u32 reset_udelay = 20000;



			port->reset_active_low = flags & OF_GPIO_ACTIVE_LOW;

			port->reset_name = kasprintf(GFP_KERNEL,

				     "pcie%d.%d-reset", port->port, port->lane);

			of_property_read_u32(child, "reset-delay-us",

					     &reset_udelay);



			ret = devm_gpio_request_one(&pdev->dev,

			    port->reset_gpio, GPIOF_DIR_OUT, port->reset_name);

			if (ret) {

				if (ret == -EPROBE_DEFER)

					return ret;

				continue;

			}



			gpio_set_value(port->reset_gpio,

				       (port->reset_active_low) ? 1 : 0);

			msleep(reset_udelay/1000);

		}



		port->clk = of_clk_get_by_name(child, NULL);

		if (IS_ERR(port->clk)) {

			dev_err(&pdev->dev, "PCIe%d.%d: cannot get clock\n",