linux-kernel - [RFC PATCH 3/4] i2c: core: treat EPROBE

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Date:   Fri, 19 Jun 2020 17:19:03 +0300
From:   Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
To:     <linux-i2c@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <wsa@...nel.org>, <robh+dt@...nel.org>,
        <ludovic.desroches@...rochip.com>, <nicolas.ferre@...rochip.com>,
        <alexandre.belloni@...tlin.com>, <linux@...linux.org.uk>,
        <kamel.bouhara@...tlin.com>,
        Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
Subject: [RFC PATCH 3/4] i2c: core: treat EPROBE_DEFER when acquiring SCL/SDA GPIOs

Even if I2C bus GPIO recovery is optional, devm_gpiod_get() can return
-EPROBE_DEFER, so we should at least treat that. This ends up with
i2c_register_adapter() to be able to return -EPROBE_DEFER.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@...rochip.com>
---
 drivers/i2c/i2c-core-base.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 4ee29fec4e93..f8d9f2048ca8 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -368,15 +368,16 @@ static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
 	return i2c_gpio_init_generic_recovery(adap);
 }
 
-static void i2c_init_recovery(struct i2c_adapter *adap)
+static int i2c_init_recovery(struct i2c_adapter *adap)
 {
 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 	char *err_str;
 
 	if (!bri)
-		return;
+		return 0;
 
-	i2c_gpio_init_recovery(adap);
+	if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	if (!bri->recover_bus) {
 		err_str = "no recover_bus() found";
@@ -392,7 +393,7 @@ static void i2c_init_recovery(struct i2c_adapter *adap)
 			if (gpiod_get_direction(bri->sda_gpiod) == 0)
 				bri->set_sda = set_sda_gpio_value;
 		}
-		return;
+		return 0;
 	}
 
 	if (bri->recover_bus == i2c_generic_scl_recovery) {
@@ -407,10 +408,12 @@ static void i2c_init_recovery(struct i2c_adapter *adap)
 		}
 	}
 
-	return;
+	return 0;
  err:
 	dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 	adap->bus_recovery_info = NULL;
+
+	return 0;
 }
 
 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
@@ -1476,7 +1479,9 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 			 "Failed to create compatibility class link\n");
 #endif
 
-	i2c_init_recovery(adap);
+	res = i2c_init_recovery(adap);
+	if (res == -EPROBE_DEFER)
+		goto out_link;
 
 	/* create pre-declared device nodes */
 	of_i2c_register_devices(adap);
@@ -1493,6 +1498,11 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 
 	return 0;
 
+out_link:
+#ifdef CONFIG_I2C_COMPAT
+	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
+				 adap->dev.parent);
+#endif
 out_reg:
 	init_completion(&adap->dev_released);
 	device_unregister(&adap->dev);
-- 
2.25.1