linux-kernel - RE: [PATCH 2/3] net: mdio-gpio: Add support for active low gpio pins

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Date:	Wed, 16 Apr 2014 02:44:53 +0000
From:	Chris Healy <chealy@...co-us.com>
To:	Guenter Roeck <linux@...ck-us.net>,
	Florian Fainelli <f.fainelli@...il.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"cphealy@...il.com" <cphealy@...il.com>
Subject: RE: [PATCH 2/3] net: mdio-gpio: Add support for active low gpio pins

Some systems using mdio-gpio may use active-low gpio pins
(eg with inverters or FETs connected to all or some of the
gpio pins).

Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Tested-by: Chris Healy <cphealy@...il.com>
---
 drivers/net/phy/mdio-gpio.c |   19 +++++++++++++------
 include/linux/mdio-gpio.h   |    3 +++
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/net/phy/mdio-gpio.c b/drivers/net/phy/mdio-gpio.c
index e853066..fac211a 100644
--- a/drivers/net/phy/mdio-gpio.c
+++ b/drivers/net/phy/mdio-gpio.c
@@ -33,28 +33,32 @@
 struct mdio_gpio_info {
        struct mdiobb_ctrl ctrl;
        int mdc, mdio;
+       int mdc_active_low, mdio_active_low;
 };

 static void *mdio_gpio_of_get_data(struct platform_device *pdev)
 {
        struct device_node *np = pdev->dev.of_node;
        struct mdio_gpio_platform_data *pdata;
+       enum of_gpio_flags flags;
        int ret;

        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return NULL;

-       ret = of_get_gpio(np, 0);
+       ret = of_get_gpio_flags(np, 0, &flags);
        if (ret < 0)
                return NULL;

        pdata->mdc = ret;
+       pdata->mdc_active_low = flags & OF_GPIO_ACTIVE_LOW;

-       ret = of_get_gpio(np, 1);
+       ret = of_get_gpio_flags(np, 1, &flags);
        if (ret < 0)
                return NULL;
        pdata->mdio = ret;
+       pdata->mdio_active_low = flags & OF_GPIO_ACTIVE_LOW;

        return pdata;
 }
@@ -65,7 +69,8 @@ static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
                container_of(ctrl, struct mdio_gpio_info, ctrl);

        if (dir)
-               gpio_direction_output(bitbang->mdio, 1);
+               gpio_direction_output(bitbang->mdio,
+                                     1 ^ bitbang->mdio_active_low);
        else
                gpio_direction_input(bitbang->mdio);
 }
@@ -75,7 +80,7 @@ static int mdio_get(struct mdiobb_ctrl *ctrl)
        struct mdio_gpio_info *bitbang =
                container_of(ctrl, struct mdio_gpio_info, ctrl);

-       return gpio_get_value(bitbang->mdio);
+       return gpio_get_value(bitbang->mdio) ^ bitbang->mdio_active_low;
 }

 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
@@ -83,7 +88,7 @@ static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
        struct mdio_gpio_info *bitbang =
                container_of(ctrl, struct mdio_gpio_info, ctrl);

-       gpio_set_value(bitbang->mdio, what);
+       gpio_set_value(bitbang->mdio, what ^ bitbang->mdio_active_low);
 }

 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
@@ -91,7 +96,7 @@ static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
        struct mdio_gpio_info *bitbang =
                container_of(ctrl, struct mdio_gpio_info, ctrl);

-       gpio_set_value(bitbang->mdc, what);
+       gpio_set_value(bitbang->mdc, what ^ bitbang->mdc_active_low);
 }

 static struct mdiobb_ops mdio_gpio_ops = {
@@ -117,7 +122,9 @@ static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
        bitbang->ctrl.ops = &mdio_gpio_ops;
        bitbang->ctrl.reset = pdata->reset;
        bitbang->mdc = pdata->mdc;
+       bitbang->mdc_active_low = pdata->mdc_active_low;
        bitbang->mdio = pdata->mdio;
+       bitbang->mdio_active_low = pdata->mdio_active_low;

        new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
        if (!new_bus)
diff --git a/include/linux/mdio-gpio.h b/include/linux/mdio-gpio.h
index 7c9fe3c..57e57fe 100644
--- a/include/linux/mdio-gpio.h
+++ b/include/linux/mdio-gpio.h
@@ -18,6 +18,9 @@ struct mdio_gpio_platform_data {
        unsigned int mdc;
        unsigned int mdio;

+       bool mdc_active_low;
+       bool mdio_active_low;
+
        unsigned int phy_mask;
        int irqs[PHY_MAX_ADDR];
        /* reset callback */
--
1.7.9.7


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