pinctrl: freescale: imx: implement gpio_disable_free for Vybrid

The Freescale Vybrid SoC has GPIO capabilities as part of the
IOMUXC. To enable GPIO's, the gpio_request_enable callback has
been implemented, however the corsponding gpio_disable_free
callback is missing. So far, disabling (unexporting) a GPIO left
the pin in its last state.

Implement a proper gpio_disable_free function which clears the
three enable bits which influence the state (IBE, OBE and PUE).

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
index a5bb939..4c435cf 100644 (file)
--- a/drivers/pinctrl/freescale/pinctrl-imx.c
+++ b/drivers/pinctrl/freescale/pinctrl-imx.c
@@ -341,6 +341,31 @@ mux_pin:
        return 0;
 }
 
+static void imx_pmx_gpio_disable_free(struct pinctrl_dev *pctldev,
+                       struct pinctrl_gpio_range *range, unsigned offset)
+{
+       struct imx_pinctrl *ipctl = pinctrl_dev_get_drvdata(pctldev);
+       const struct imx_pinctrl_soc_info *info = ipctl->info;
+       const struct imx_pin_reg *pin_reg;
+       u32 reg;
+
+       /*
+        * Only Vybrid has the input/output buffer enable flags (IBE/OBE)
+        * They are part of the shared mux/conf register.
+        */
+       if (!(info->flags & SHARE_MUX_CONF_REG))
+               return;
+
+       pin_reg = &info->pin_regs[offset];
+       if (pin_reg->mux_reg == -1)
+               return;
+
+       /* Clear IBE/OBE/PUE to disable the pin (Hi-Z) */
+       reg = readl(ipctl->base + pin_reg->mux_reg);
+       reg &= ~0x7;
+       writel(reg, ipctl->base + pin_reg->mux_reg);
+}
+
 static int imx_pmx_gpio_set_direction(struct pinctrl_dev *pctldev,
           struct pinctrl_gpio_range *range, unsigned offset, bool input)
 {
@@ -377,6 +402,7 @@ static const struct pinmux_ops imx_pmx_ops = {
        .get_function_groups = imx_pmx_get_groups,
        .set_mux = imx_pmx_set,
        .gpio_request_enable = imx_pmx_gpio_request_enable,
+       .gpio_disable_free = imx_pmx_gpio_disable_free,
        .gpio_set_direction = imx_pmx_gpio_set_direction,
 };