netdev - [PATCH v3] net: fec: Do a sanity check on the gpio number

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Message-Id: <1361114964-10517-1-git-send-email-festevam@gmail.com>
Date:	Sun, 17 Feb 2013 12:29:24 -0300
From:	Fabio Estevam <festevam@...il.com>
To:	davem@...emloft.net
Cc:	s.hauer@...gutronix.de, shawn.guo@...aro.org, marex@...x.de,
	netdev@...r.kernel.org, Fabio Estevam <fabio.estevam@...escale.com>
Subject: [PATCH v3] net: fec: Do a sanity check on the gpio number

From: Fabio Estevam <fabio.estevam@...escale.com>

Since commit 372e722ea4d (gpiolib: use descriptors internally) the following 
warning is seen on a mx28evk board:

[    5.116291] ------------[ cut here ]------------
[    5.121306] WARNING: at drivers/gpio/gpiolib.c:125 gpio_to_desc+0x30/0x44()
[    5.128491] invalid GPIO -2
[    5.131563] Modules linked in:
[    5.134846] [<c0014e20>] (unwind_backtrace+0x0/0xf4) from [<c001d428>] (warn_slowpath_common+0x4c/0x68)
[    5.144682] [<c001d428>] (warn_slowpath_common+0x4c/0x68) from [<c001d4d8>] (warn_slowpath_fmt+0x30/0x40)
[    5.154693] [<c001d4d8>] (warn_slowpath_fmt+0x30/0x40) from [<c0283434>] (gpio_to_desc+0x30/0x44)
[    5.164002] [<c0283434>] (gpio_to_desc+0x30/0x44) from [<c0285470>] (gpio_request_one+0x10/0xe8)
[    5.173294] [<c0285470>] (gpio_request_one+0x10/0xe8) from [<c0282f50>] (devm_gpio_request_one+0x40/0x74)
[    5.183332] [<c0282f50>] (devm_gpio_request_one+0x40/0x74) from [<c0319be0>] (fec_probe+0x2d0/0x99c)
[    5.192923] [<c0319be0>] (fec_probe+0x2d0/0x99c) from [<c02c8114>] (platform_drv_probe+0x14/0x18)
[    5.202228] [<c02c8114>] (platform_drv_probe+0x14/0x18) from [<c02c6e00>] (driver_probe_device+0x90/0x224)
[    5.212332] [<c02c6e00>] (driver_probe_device+0x90/0x224) from [<c02c7028>] (__driver_attach+0x94/0x98)
[    5.222162] [<c02c7028>] (__driver_attach+0x94/0x98) from [<c02c5750>] (bus_for_each_dev+0x78/0x98)
[    5.231642] [<c02c5750>] (bus_for_each_dev+0x78/0x98) from [<c02c5fd0>] (bus_add_driver+0x1a4/0x240)
[    5.241207] [<c02c5fd0>] (bus_add_driver+0x1a4/0x240) from [<c02c7608>] (driver_register+0x78/0x140)
[    5.250768] [<c02c7608>] (driver_register+0x78/0x140) from [<c00087a4>] (do_one_initcall+0x30/0x17c)
[    5.260347] [<c00087a4>] (do_one_initcall+0x30/0x17c) from [<c05fa29c>] (kernel_init_freeable+0xe8/0x1b0)
[    5.270381] [<c05fa29c>] (kernel_init_freeable+0xe8/0x1b0) from [<c044dfd4>] (kernel_init+0x8/0xe4)
[    5.279886] [<c044dfd4>] (kernel_init+0x8/0xe4) from [<c000f248>] (ret_from_fork+0x14/0x2c)
[    5.288740] ---[ end trace c15c72a22979d58d ]--- 

mx28evk has two ethernet controllers. The GPIO that performs the 
ethernet reset on both ports is the same GPIO, so on the board dts file, only in
one ethernet instance is passed the GPIO reset property.

Validate the gpio number prior to requesting it in order to avoid such warning.

With such gpio validation in place, it is also safe to change from pr_debug to 
dev_err in the case the gpio request fails.

Signed-off-by: Fabio Estevam <fabio.estevam@...escale.com>
---
Changes since v2:
- Merge the two patches into a single one, and use dev_err
Changes since v1:
- Added Shawn's ack
 drivers/net/ethernet/freescale/fec.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
index 0fe68c4..1a2071b 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -1689,10 +1689,13 @@ static void fec_reset_phy(struct platform_device *pdev)
 		msec = 1;
 
 	phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
+	if (!gpio_is_valid(phy_reset))
+		return;
+
 	err = devm_gpio_request_one(&pdev->dev, phy_reset,
 				    GPIOF_OUT_INIT_LOW, "phy-reset");
 	if (err) {
-		pr_debug("FEC: failed to get gpio phy-reset: %d\n", err);
+		dev_err(&pdev->dev, "failed to get phy-reset-gpios: %d\n", err);
 		return;
 	}
 	msleep(msec);
-- 
1.7.9.5

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