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>

diff --git a/Documentation/devicetree/bindings/pci/mvebu-pci.txt b/Documentation/devicetree/bindings/pci/mvebu-pci.txt
index 638673aec306d1b48130367143e3bd11b14ad506..8bb3245e1946cd4dbbd758d3582b3f0b230c85f7 100644 (file)
--- a/Documentation/devicetree/bindings/pci/mvebu-pci.txt
+++ b/Documentation/devicetree/bindings/pci/mvebu-pci.txt
@@ -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";
        };

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index af23038a52ac3394ef1b93ff65dbd985640170c3..2d5f414bc45ae84a6ce420d182a2edd3568a3546 100644 (file)
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -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",