Subject: [PATCH 1/2] net: fec: Do a sanity check on the gpio number

From: Fabio Estevam <[email-masked]>
Date: Sat, 16 Feb 2013 20:53:26 -0200

From: Fabio Estevam <[email-masked]>

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.

Signed-off-by: Fabio Estevam <[email-masked]>
---
 drivers/net/ethernet/freescale/fec.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
index 0fe68c4..5864a67 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -1689,6 +1689,9 @@ 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) {
-- 
1.7.9.5