[PATCH v2] net: stmmac: Use msleep rather then udelay for reset delay

[PATCH v2] 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>

---

Changes in v2:
- Use DIV_ROUND_UP instead of handcoding the same

 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..ebf6abc 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(DIV_ROUND_UP(data->delays[0], 1000));
+
 			gpio_set_value(reset_gpio, active_low ? 0 : 1);
-			udelay(data->delays[1]);
+			if (data->delays[1])
+				msleep(DIV_ROUND_UP(data->delays[1], 1000));
+
 			gpio_set_value(reset_gpio, active_low ? 1 : 0);
-			udelay(data->delays[2]);
+			if (data->delays[2])
+				msleep(DIV_ROUND_UP(data->delays[2], 1000));
 		}
 	}
 #endif
-- 
2.5.1

Re: [PATCH v2] net: stmmac: Use msleep rather then udelay for reset delay

[David Miller]

From: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Date: Fri, 11 Sep 2015 22:25:48 +0200

> 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>

Applied, thanks.