linux-kernel - [PATCH 4/5] W1: w1-gpio - rework handling of platform data

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Date:	Sun, 24 Feb 2013 22:59:36 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	Evgeniy Polyakov <zbr@...emap.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Ville Syrjala <syrjala@....fi>, Daniel Mack <zonque@...il.com>,
	Matt Ranostay <mranostay@...il.com>,
	panto@...oniou-consulting.com, koen@...inion.thruhere.net
Subject: [PATCH 4/5] W1: w1-gpio - rework handling of platform data

The platform data in the dveice structure does not belong to the driver
and so it should not be trying to alter it, but instead use a local pointer
and populate it with a local copy in case we are dealing with device tree
setup.

Also allow mixed setups where platform data coexists with device tree and
prefer kernel-supplied data (it may be easier to fiddle in kernel structure
before committing final result to device tree).

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---
 drivers/w1/masters/w1-gpio.c | 44 +++++++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index aa97a96..465ce52 100644
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -55,30 +55,34 @@ static struct of_device_id w1_gpio_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
 
-static int w1_gpio_probe_dt(struct platform_device *pdev)
+static struct w1_gpio_platform_data *
+w1_gpio_probe_dt(struct platform_device *pdev)
 {
-	struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+	struct w1_gpio_platform_data *pdata;
 	struct device_node *np = pdev->dev.of_node;
 
+	if (!np)
+		return ERR_PTR(-ENOENT);
+
 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	if (of_get_property(np, "linux,open-drain", NULL))
 		pdata->is_open_drain = 1;
 
 	pdata->pin = of_get_gpio(np, 0);
 	pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
-	pdev->dev.platform_data = pdata;
 
-	return 0;
+	return pdata;
 }
 
 #else
 
-static inline int w1_gpio_probe_dt(struct platform_device *pdev)
+static inline struct w1_gpio_platform_data *
+w1_gpio_probe_dt(struct platform_device *pdev)
 {
-	return -ENOSYS;
+	return NULL;
 }
 
 #endif
@@ -94,19 +98,17 @@ static int w1_gpio_probe(struct platform_device *pdev)
 	if (IS_ERR(pinctrl))
 		dev_warn(&pdev->dev, "unable to select pin group\n");
 
-	if (of_have_populated_dt()) {
-		err = w1_gpio_probe_dt(pdev);
-		if (err < 0) {
-			dev_err(&pdev->dev, "Failed to parse DT\n");
-			return err;
-		}
-	}
-
-	pdata = pdev->dev.platform_data;
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata)
+		pdata = w1_gpio_probe_dt(pdev);
 
 	if (!pdata) {
 		dev_err(&pdev->dev, "No configuration data\n");
 		return -ENXIO;
+	} else if (IS_ERR(pdata)) {
+		err = PTR_ERR(pdata);
+		dev_err(&pdev->dev, "Failed to parse DT\n");
+		return err;
 	}
 
 	master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
@@ -172,7 +174,7 @@ static int w1_gpio_probe(struct platform_device *pdev)
 static int w1_gpio_remove(struct platform_device *pdev)
 {
 	struct w1_bus_master *master = platform_get_drvdata(pdev);
-	struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+	const struct w1_gpio_platform_data *pdata = master->data;
 
 	if (pdata->enable_external_pullup)
 		pdata->enable_external_pullup(0);
@@ -190,7 +192,9 @@ static int w1_gpio_remove(struct platform_device *pdev)
 #ifdef CONFIG_PM_SLEEP
 static int w1_gpio_suspend(struct device *dev)
 {
-	const struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
+	struct platform_device *pdev = to_platform_device(dev);
+	struct w1_bus_master *master = platform_get_drvdata(pdev);
+	const struct w1_gpio_platform_data *pdata = master->data;
 
 	if (pdata->enable_external_pullup)
 		pdata->enable_external_pullup(0);
@@ -200,7 +204,9 @@ static int w1_gpio_suspend(struct device *dev)
 
 static int w1_gpio_resume(struct device *dev)
 {
-	const struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
+	struct platform_device *pdev = to_platform_device(dev);
+	struct w1_bus_master *master = platform_get_drvdata(pdev);
+	const struct w1_gpio_platform_data *pdata = master->data;
 
 	if (pdata->enable_external_pullup)
 		pdata->enable_external_pullup(1);
-- 
1.7.11.7

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