| Message ID | 1473256422-14012-1-git-send-email-linus.walleij@linaro.org |
|---|---|
| State | New |
| Headers | show |
From: Linus Walleij <linus.walleij@linaro.org> Date: Wed, 7 Sep 2016 15:53:42 +0200 > On some systems (such as the Qualcomm APQ8060 Dragonboard) the > RESET signal of the SMSC911x is not pulled up by a resistor (or > the internal pull-up that will pull it up if the pin is not > even connected) but instead connected to a GPIO line, so that > the operating system must explicitly deassert RESET before use. > > Support this in the SMSC911x driver so this ethernet connector > can be used on such targets. > > Notice that we request the line to go logical low (deassert) > whilst the line on the actual component is active low. This > is managed in the respective hardware description when > specifying the GPIO line with e.g. device tree or ACPI. With > device tree it looks like this in one case: > > reset-gpios = <&tlmm 30 GPIO_ACTIVE_LOW>; > > Which means that logically requesting the RESET line to be > deasserted will result in the line being driven high, taking > the device out of reset. > > Cc: Jeremy Linton <jeremy.linton@arm.com> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Applied.
diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c index ca3134540d2d..8ab8d4b9614b 100644 --- a/drivers/net/ethernet/smsc/smsc911x.c +++ b/drivers/net/ethernet/smsc/smsc911x.c @@ -62,6 +62,7 @@ #include <linux/acpi.h> #include <linux/pm_runtime.h> #include <linux/property.h> +#include <linux/gpio/consumer.h> #include "smsc911x.h" @@ -147,6 +148,9 @@ struct smsc911x_data { /* regulators */ struct regulator_bulk_data supplies[SMSC911X_NUM_SUPPLIES]; + /* Reset GPIO */ + struct gpio_desc *reset_gpiod; + /* clock */ struct clk *clk; }; @@ -438,6 +442,11 @@ static int smsc911x_request_resources(struct platform_device *pdev) netdev_err(ndev, "couldn't get regulators %d\n", ret); + /* Request optional RESET GPIO */ + pdata->reset_gpiod = devm_gpiod_get_optional(&pdev->dev, + "reset", + GPIOD_OUT_LOW); + /* Request clock */ pdata->clk = clk_get(&pdev->dev, NULL); if (IS_ERR(pdata->clk))
On some systems (such as the Qualcomm APQ8060 Dragonboard) the RESET signal of the SMSC911x is not pulled up by a resistor (or the internal pull-up that will pull it up if the pin is not even connected) but instead connected to a GPIO line, so that the operating system must explicitly deassert RESET before use. Support this in the SMSC911x driver so this ethernet connector can be used on such targets. Notice that we request the line to go logical low (deassert) whilst the line on the actual component is active low. This is managed in the respective hardware description when specifying the GPIO line with e.g. device tree or ACPI. With device tree it looks like this in one case: reset-gpios = <&tlmm 30 GPIO_ACTIVE_LOW>; Which means that logically requesting the RESET line to be deasserted will result in the line being driven high, taking the device out of reset. Cc: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- ChangeLog v2->v3: - Specify in the commit message that the component has an internal pull-up that will act if the RESET line is not connected. - Specify in the commit message that the hardware description such as device tree or ACPI is responsible of flagging the line as active low. ChangeLog v1->v2: - Use devm_gpiod_request_optiona() and request the line with GPIOD_OUT_LOW so it is deasserted immediately if active. --- drivers/net/ethernet/smsc/smsc911x.c | 9 +++++++++ 1 file changed, 9 insertions(+) -- 2.7.4