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@xxxxxxxxx>
---
Changelog:
v1->v2:
- use reset API compatible bindings (Reported by Kumar Gala and Thierry
Reding)
- add gpio properties to DT examples (Reported by Kumar Gala)
- only fail (return) on EPROBE_DEFER and skip port parsing otherwise
- use us delay instead of ms delay
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Andrew Lunn <andrew@xxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Cc: Stephen Warren <swarren@xxxxxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-pci@xxxxxxxxxxxxxxx
---
.../devicetree/bindings/pci/mvebu-pci.txt | 6 ++++
drivers/pci/host/pci-mvebu.c | 33 +++++++++++++++++++-
2 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/pci/mvebu-pci.txt b/Documentation/devicetree/bindings/pci/mvebu-pci.txt
index 638673a..8bb3245 100644
--- 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 bd7092a..a9ad4b3 100644
--- 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);
+ udelay(reset_udelay);
+ }
+
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",
--
1.7.10.4
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