gpio: mvebu: Add clk support to prevent lockup

commit de88747f514a4e0cca416a8871de2302f4f77790 upstream.

The kirkwood SoC GPIO cores use the runit clock. Add code to
clk_prepare_enable() runit, otherwise there is a danger of locking up
the SoC by accessing the GPIO registers when runit clock is not
ticking.

Reported-by: Simon Baatz <gmbnomis@gmail.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Simon Baatz <gmbnomis@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/boot/dts/kirkwood.dtsi b/arch/arm/boot/dts/kirkwood.dtsi
index 578466e90b0b1479680525dcf73024abbfc478d3..c57b9c64d5e8227039a6c2cdee0445bccb441d7f 100644 (file)
--- a/arch/arm/boot/dts/kirkwood.dtsi
+++ b/arch/arm/boot/dts/kirkwood.dtsi
@@ -38,6 +38,7 @@
                        interrupt-controller;
                        #interrupt-cells = <2>;
                        interrupts = <35>, <36>, <37>, <38>;
+                       clocks = <&gate_clk 7>;
                };
 
                gpio1: gpio@10140 {
@@ -49,6 +50,7 @@
                        interrupt-controller;
                        #interrupt-cells = <2>;
                        interrupts = <39>, <40>, <41>;
+                       clocks = <&gate_clk 7>;
                };
 
                serial@12000 {

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index 6819d63cb1673647e35821ce3feede298e3e56c7..456663c02997b61a8fcb65993a367e87519ee380 100644 (file)
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -41,6 +41,7 @@
 #include <linux/io.h>
 #include <linux/of_irq.h>
 #include <linux/of_device.h>
+#include <linux/clk.h>
 #include <linux/pinctrl/consumer.h>
 
 /*
@@ -495,6 +496,7 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
        struct resource *res;
        struct irq_chip_generic *gc;
        struct irq_chip_type *ct;
+       struct clk *clk;
        unsigned int ngpios;
        int soc_variant;
        int i, cpu, id;
@@ -528,6 +530,11 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
                return id;
        }
 
+       clk = devm_clk_get(&pdev->dev, NULL);
+       /* Not all SoCs require a clock.*/
+       if (!IS_ERR(clk))
+               clk_prepare_enable(clk);
+
        mvchip->soc_variant = soc_variant;
        mvchip->chip.label = dev_name(&pdev->dev);
        mvchip->chip.dev = &pdev->dev;