linux-kernel - [PATCH 3/4] i2c: core: treat EPROBE_DEFER when acquiring SCL/SDA GPIOs

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Message-ID: <20200804095926.205643-4-codrin.ciubotariu@microchip.com>
Date:   Tue, 4 Aug 2020 12:59:25 +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: [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>
---

Changes from RFC:
 - return -EINVAL if i2c_init_recovery() doesn't have the complete
   information;
 - 'else if' added when checking if i2c_generic_scl_recovery() is used;
 - moved i2c_init_recovery() before class-link creation; class-link
   cleanup removed;
 - moved debug print when the adapter is probed after call to
   i2c_init_recovery();

 drivers/i2c/i2c-core-base.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index cf0c5eb152e1..99dbaead269e 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -375,15 +375,16 @@ 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";
@@ -399,10 +400,7 @@ 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;
-	}
-
-	if (bri->recover_bus == i2c_generic_scl_recovery) {
+	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
 		/* Generic SCL recovery */
 		if (!bri->set_scl || !bri->get_scl) {
 			err_str = "no {get|set}_scl() found";
@@ -414,10 +412,12 @@ 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 -EINVAL;
 }
 
 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
@@ -1444,12 +1444,16 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	if (res)
 		goto out_reg;
 
-	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
-
 	pm_runtime_no_callbacks(&adap->dev);
 	pm_suspend_ignore_children(&adap->dev, true);
 	pm_runtime_enable(&adap->dev);
 
+	res = i2c_init_recovery(adap);
+	if (res == -EPROBE_DEFER)
+		goto out_reg;
+
+	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
+
 #ifdef CONFIG_I2C_COMPAT
 	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
 				       adap->dev.parent);
@@ -1458,8 +1462,6 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 			 "Failed to create compatibility class link\n");
 #endif
 
-	i2c_init_recovery(adap);
-
 	/* create pre-declared device nodes */
 	of_i2c_register_devices(adap);
 	i2c_acpi_register_devices(adap);
-- 
2.25.1