Hi,
On 05/04/17 18:03, Andrew Lunn wrote:
> 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 <rogerq@xxxxxx>
>> Signed-off-by: Sekhar Nori <nsekhar@xxxxxx>
>> ---
>> .../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.
>
Yes we need. Some of our boards have separate GPIO RESET lines for
different PHYs on the same MDIO bus.
cheers,
-roger
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
