[U-Boot] [PATCH v2 1/2] dm: pinctrl: Avoid race condition on probe for UCLASS_PINCTRL

Patrice Chotard patrice.chotard at st.com
Mon Feb 25 12:39:55 UTC 2019


In case of system with several pin-controller device, probe the first
UCLASS_PINCTRL by seq number (defined by alias) to avoid race condition
with I2C PINCONTROL driver for GPIO expander (GPIO expander need I2C bus,
I2C driver need PINCONFIG).

Signed-off-by: Patrick DELAUNAY <patrick.delaunay at st.com>
Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---

Changes in v2: None

 drivers/pinctrl/pinctrl-uclass.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-uclass.c b/drivers/pinctrl/pinctrl-uclass.c
index 0e3260afd1ee..abb622cfe79e 100644
--- a/drivers/pinctrl/pinctrl-uclass.c
+++ b/drivers/pinctrl/pinctrl-uclass.c
@@ -201,11 +201,14 @@ static int pinctrl_select_state_simple(struct udevice *dev)
 	int ret;
 
 	/*
-	 * For simplicity, assume the first device of PINCTRL uclass
-	 * is the correct one.  This is most likely OK as there is
-	 * usually only one pinctrl device on the system.
+	 * For most system, there is only one pincontroller device. But in
+	 * case of multiple pincontroller devices, probe the one with sequence
+	 * number 0 (defined by alias) to avoid race condition.
 	 */
-	ret = uclass_get_device(UCLASS_PINCTRL, 0, &pctldev);
+	ret = uclass_get_device_by_seq(UCLASS_PINCTRL, 0, &pctldev);
+	if (ret)
+		/* if not found, get the first one */
+		ret = uclass_get_device(UCLASS_PINCTRL, 0, &pctldev);
 	if (ret)
 		return ret;
 
-- 
1.9.1



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