gpio: mxc: add clock operation

Some i.MX SoCs have GPIO clock gates in CCM CCGR, such as
i.MX6SLL, need to enable clocks before accessing GPIO
registers, add optional clock operation for GPIO driver.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
index 11ec7228ab083554222d4a737d90332db59c6479..f4dc31d88a04f5375ec02722d42fc81f6b57dba6 100644 (file)
--- a/drivers/gpio/gpio-mxc.c
+++ b/drivers/gpio/gpio-mxc.c
@@ -20,6 +20,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 

+#include <linux/clk.h>

 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>


@@ -60,6 +61,7 @@ struct mxc_gpio_hwdata {
 struct mxc_gpio_port {
        struct list_head node;
        void __iomem *base;
 struct mxc_gpio_port {
        struct list_head node;
        void __iomem *base;

+       struct clk *clk;

        int irq;
        int irq_high;
        struct irq_domain *domain;
        int irq;
        int irq_high;
        struct irq_domain *domain;


@@ -434,6 +436,17 @@ static int mxc_gpio_probe(struct platform_device *pdev)
        if (port->irq < 0)
                return port->irq;
 
        if (port->irq < 0)
                return port->irq;
 

+       /* the controller clock is optional */
+       port->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(port->clk))
+               port->clk = NULL;
+
+       err = clk_prepare_enable(port->clk);
+       if (err) {
+               dev_err(&pdev->dev, "Unable to enable clock.\n");
+               return err;
+       }
+

        /* disable the interrupt and clear the status */
        writel(0, port->base + GPIO_IMR);
        writel(~0, port->base + GPIO_ISR);
        /* disable the interrupt and clear the status */
        writel(0, port->base + GPIO_IMR);
        writel(~0, port->base + GPIO_ISR);


@@ -502,6 +515,7 @@ static int mxc_gpio_probe(struct platform_device *pdev)
 out_irqdomain_remove:
        irq_domain_remove(port->domain);
 out_bgio:
 out_irqdomain_remove:
        irq_domain_remove(port->domain);
 out_bgio:

+       clk_disable_unprepare(port->clk);

        dev_info(&pdev->dev, "%s failed with errno %d\n", __func__, err);
        return err;
 }
        dev_info(&pdev->dev, "%s failed with errno %d\n", __func__, err);
        return err;
 }