gpio: mvebu: Add clk support to prevent lockup

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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

diff --git a/arch/arm/boot/dts/kirkwood.dtsi b/arch/arm/boot/dts/kirkwood.dtsi
index 19709fbe12cf5d4052edde715613e997cec6eb33..cf8e8926a034047f7203342b25df5312b6884227 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 7472182967ce15b44d964d184038fbca247724e8..61a6fde6c089b28a76f3ca5012309c101ebcf2b2 100644 (file)
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -42,6 +42,7 @@
 #include <linux/io.h>
 #include <linux/of_irq.h>
 #include <linux/of_device.h>
+#include <linux/clk.h>
 #include <linux/pinctrl/consumer.h>
 
 /*
@@ -496,6 +497,7 @@ 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;
@@ -529,6 +531,11 @@ 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;