[PATCH] net: stmmac: Use msleep rather then udelay for reset delay

[PATCH] net: stmmac: Use msleep rather then udelay for reset delay

[Sjoerd Simons]

The reset delays used for stmmac are in the order of 10ms to 1 second,
which is far too long for udelay usage, so switch to using msleep.

Practically this fixes the PHY not being reliably detected in some cases
as udelay wouldn't actually delay for long enough to let the phy
reliably be reset.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
---

 drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index b735fa2..17fa588 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -161,11 +161,16 @@ int stmmac_mdio_reset(struct mii_bus *bus)
 
 		if (!gpio_request(reset_gpio, "mdio-reset")) {
 			gpio_direction_output(reset_gpio, active_low ? 1 : 0);
-			udelay(data->delays[0]);
+			if (data->delays[0])
+				msleep((data->delays[0] + 999) / 1000);
+
 			gpio_set_value(reset_gpio, active_low ? 0 : 1);
-			udelay(data->delays[1]);
+			if (data->delays[1])
+				msleep((data->delays[1] + 999) / 1000);
+
 			gpio_set_value(reset_gpio, active_low ? 1 : 0);
-			udelay(data->delays[2]);
+			if (data->delays[2])
+				msleep((data->delays[2] + 999) / 1000);
 		}
 	}
 #endif
-- 
2.5.1

Re: [PATCH] net: stmmac: Use msleep rather then udelay for reset delay

[David Miller]

From: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Date: Sun,  6 Sep 2015 17:50:59 +0200

> @@ -161,11 +161,16 @@ int stmmac_mdio_reset(struct mii_bus *bus)
>  
>  		if (!gpio_request(reset_gpio, "mdio-reset")) {
>  			gpio_direction_output(reset_gpio, active_low ? 1 : 0);
> -			udelay(data->delays[0]);
> +			if (data->delays[0])
> +				msleep((data->delays[0] + 999) / 1000);

Please use something like DIV_ROUND_UP(..., USEC_PER_MSEC) or similar.