linux-kernel - [PATCH net-next v2] net: phy: micrel: Make the GPIO to be non-exclusive

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Message-ID: <20220825201447.1444396-1-horatiu.vultur@microchip.com>
Date:   Thu, 25 Aug 2022 22:14:47 +0200
From:   Horatiu Vultur <horatiu.vultur@...rochip.com>
To:     <andrew@...n.ch>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <hkallweit1@...il.com>, <linux@...linux.org.uk>,
        <davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
        <pabeni@...hat.com>, <michael@...le.cc>,
        <UNGLinuxDriver@...rochip.com>, <maxime.chevallier@...tlin.com>,
        Horatiu Vultur <horatiu.vultur@...rochip.com>
Subject: [PATCH net-next v2] net: phy: micrel: Make the GPIO to be non-exclusive

The same GPIO line can be shared by multiple phys for the coma mode pin.
If that is the case then, all the other phys that share the same line
will failed to be probed because the access to the gpio line is not
non-exclusive.
Fix this by making access to the gpio line to be nonexclusive using flag
GPIOD_FLAGS_BIT_NONEXCLUSIVE. This allows all the other PHYs to be
probed.

Fixes: 738871b09250ee ("net: phy: micrel: add coma mode GPIO")
Signed-off-by: Horatiu Vultur <horatiu.vultur@...rochip.com>
---
v1->v2:
- add comment describing that there should not be anyone putting back
  the phy in coma mode.
---
 drivers/net/phy/micrel.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index e78d0bf69bc3..6f52b4fb6888 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -2873,12 +2873,18 @@ static int lan8814_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+/* It is expected that there will not be any 'lan8814_take_coma_mode'
+ * function called in suspend. Because the GPIO line can be shared, so if one of
+ * the phys goes back in coma mode, then all the other PHYs will go, which is
+ * wrong.
+ */
 static int lan8814_release_coma_mode(struct phy_device *phydev)
 {
 	struct gpio_desc *gpiod;
 
 	gpiod = devm_gpiod_get_optional(&phydev->mdio.dev, "coma-mode",
-					GPIOD_OUT_HIGH_OPEN_DRAIN);
+					GPIOD_OUT_HIGH_OPEN_DRAIN |
+					GPIOD_FLAGS_BIT_NONEXCLUSIVE);
 	if (IS_ERR(gpiod))
 		return PTR_ERR(gpiod);
 
-- 
2.33.0