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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: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
This commit is contained in:
Sebastian Hesselbarth 2013-08-13 14:25:23 +02:00 committed by Jason Cooper
parent e5615c30c1
commit 52ba992e20
2 changed files with 38 additions and 1 deletions
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6
Documentation/devicetree/bindings/pci/mvebu-pci.txt
View File

@ -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";
};

33
drivers/pci/host/pci-mvebu.c
View File

@ -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",