On Wed, Apr 05, 2017 at 11:33:57AM +0300, Roger Quadros wrote:
> Some boards [1] leave the PHYs at an invalid state
> during system power-up or reset thus causing unreliability
> issues with the PHY like not being detected by the mdio bus
> or link not functional. To work around these boards have
> a GPIO connected to the PHY's reset pin.
>
> Implement GPIO reset handling for such cases.
>
> [1] - am572x-idk, am571x-idk, a437x-idk.
>
> Signed-off-by: Roger Quadros <rog...@ti.com>
> Signed-off-by: Sekhar Nori <nsek...@ti.com>
> ---
> .../devicetree/bindings/net/davinci-mdio.txt | 2 +
> drivers/net/ethernet/ti/davinci_mdio.c | 68
> +++++++++++++++++++---
> 2 files changed, 62 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/davinci-mdio.txt
> b/Documentation/devicetree/bindings/net/davinci-mdio.txt
> index 621156c..fd6ebe7 100644
> --- a/Documentation/devicetree/bindings/net/davinci-mdio.txt
> +++ b/Documentation/devicetree/bindings/net/davinci-mdio.txt
> @@ -12,6 +12,8 @@ Required properties:
>
> Optional properties:
> - ti,hwmods : Must be "davinci_mdio"
> +- reset-gpios : array of GPIO specifier for PHY hardware
> reset control
> +- reset-delay-us : reset assertion time [in microseconds]
>
> Note: "ti,hwmods" field is used to fetch the base address and irq
> resources from TI, omap hwmod data base during device registration.
> diff --git a/drivers/net/ethernet/ti/davinci_mdio.c
> b/drivers/net/ethernet/ti/davinci_mdio.c
> index 33df340..c6f9e55 100644
> --- a/drivers/net/ethernet/ti/davinci_mdio.c
> +++ b/drivers/net/ethernet/ti/davinci_mdio.c
> @@ -40,6 +40,9 @@
> #include <linux/of_device.h>
> #include <linux/of_mdio.h>
> #include <linux/pinctrl/consumer.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/of_gpio.h>
>
> /*
> * This timeout definition is a worst-case ultra defensive measure against
> @@ -53,6 +56,8 @@
>
> #define DEF_OUT_FREQ 2200000 /* 2.2 MHz */
>
> +#define DEFAULT_GPIO_RESET_DELAY 10 /* in microseconds */
> +
> struct davinci_mdio_of_param {
> int autosuspend_delay_ms;
> };
> @@ -104,6 +109,9 @@ struct davinci_mdio_data {
> */
> bool skip_scan;
> u32 clk_div;
> + struct gpio_desc **gpio_reset;
> + int num_gpios;
> + int reset_delay_us;
> };
>
> static void davinci_mdio_init_clk(struct davinci_mdio_data *data)
> @@ -142,6 +150,20 @@ static void davinci_mdio_enable(struct davinci_mdio_data
> *data)
> __raw_writel(data->clk_div | CONTROL_ENABLE, &data->regs->control);
> }
>
> +static void __davinci_gpio_reset(struct davinci_mdio_data *data)
> +{
> + int i;
> +
> + for (i = 0; i < data->num_gpios; i++) {
> + if (!data->gpio_reset[i])
> + continue;
> +
> + gpiod_set_value_cansleep(data->gpio_reset[i], 1);
> + udelay(data->reset_delay_us);
> + gpiod_set_value_cansleep(data->gpio_reset[i], 0);
> + }
> +}
Do you really need more than one GPIO? A single gpio would make all
this code a lot simpler.
Andrew
