[PATCH] i2c: stu300: use devm managed resources

[PATCH] i2c: stu300: use devm managed resources

[Linus Walleij]

Allocate memory for device state using devm_kzalloc(), get the
clock using devm_clk_get(), get the IRQ using devm_request_irq(),
request and remap memory using devm_request_and_ioremap().
All to simplify accounting and letting the kernel do the
garbage-collection.

Signed-off-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
ChangeLog v2->v3:
- Also delete the cached physical base and size from the state
  holder struct.
ChangeLog v1->v2:
- Use more devm* stuff, at Wolfram's request.
- Note: based on a clean v3.5-rc6, may need some patch -p1 < patch
  to apply on the i2c tree, if you want me to rebase it, just tell
  me where to find the baseline.
---
 drivers/i2c/busses/i2c-stu300.c |   81 +++++++++------------------------------
 1 files changed, 18 insertions(+), 63 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stu300.c b/drivers/i2c/busses/i2c-stu300.c
index 4d44af1..a051eae 100644
--- a/drivers/i2c/busses/i2c-stu300.c
+++ b/drivers/i2c/busses/i2c-stu300.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2007-2009 ST-Ericsson AB
+ * Copyright (C) 2007-2012 ST-Ericsson AB
  * License terms: GNU General Public License (GPL) version 2
  * ST DDC I2C master mode driver, used in e.g. U300 series platforms.
  * Author: Linus Walleij <linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>
@@ -139,8 +139,6 @@ module_param(scl_frequency, uint,  0644);
  * struct stu300_dev - the stu300 driver state holder
  * @pdev: parent platform device
  * @adapter: corresponding I2C adapter
- * @phybase: location of I/O area in memory
- * @physize: size of I/O area in memory
  * @clk: hardware block clock
  * @irq: assigned interrupt line
  * @cmd_issue_lock: this locks the following cmd_ variables
@@ -155,8 +153,6 @@ module_param(scl_frequency, uint,  0644);
 struct stu300_dev {
 	struct platform_device	*pdev;
 	struct i2c_adapter	adapter;
-	resource_size_t		phybase;
-	resource_size_t		physize;
 	void __iomem		*virtbase;
 	struct clk		*clk;
 	int			irq;
@@ -873,64 +869,44 @@ stu300_probe(struct platform_device *pdev)
 	int ret = 0;
 	char clk_name[] = "I2C0";
 
-	dev = kzalloc(sizeof(struct stu300_dev), GFP_KERNEL);
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct stu300_dev), GFP_KERNEL);
 	if (!dev) {
 		dev_err(&pdev->dev, "could not allocate device struct\n");
-		ret = -ENOMEM;
-		goto err_no_devmem;
+		return -ENOMEM;
 	}
 
 	bus_nr = pdev->id;
 	clk_name[3] += (char)bus_nr;
-	dev->clk = clk_get(&pdev->dev, clk_name);
+	dev->clk = devm_clk_get(&pdev->dev, clk_name);
 	if (IS_ERR(dev->clk)) {
-		ret = PTR_ERR(dev->clk);
 		dev_err(&pdev->dev, "could not retrieve i2c bus clock\n");
-		goto err_no_clk;
+		return PTR_ERR(dev->clk);
 	}
 
 	dev->pdev = pdev;
-	platform_set_drvdata(pdev, dev);
-
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		ret = -ENOENT;
-		goto err_no_resource;
-	}
+	if (!res)
+		return -ENOENT;
 
-	dev->phybase = res->start;
-	dev->physize = resource_size(res);
-
-	if (request_mem_region(dev->phybase, dev->physize,
-			       NAME " I/O Area") == NULL) {
-		ret = -EBUSY;
-		goto err_no_ioregion;
-	}
-
-	dev->virtbase = ioremap(dev->phybase, dev->physize);
+	dev->virtbase = devm_request_and_ioremap(&pdev->dev, res);
 	dev_dbg(&pdev->dev, "initialize bus device I2C%d on virtual "
 		"base %p\n", bus_nr, dev->virtbase);
-	if (!dev->virtbase) {
-		ret = -ENOMEM;
-		goto err_no_ioremap;
-	}
+	if (!dev->virtbase)
+		return -ENOMEM;
 
 	dev->irq = platform_get_irq(pdev, 0);
-	if (request_irq(dev->irq, stu300_irh, 0,
-			NAME, dev)) {
-		ret = -EIO;
-		goto err_no_irq;
-	}
+	ret = devm_request_irq(&pdev->dev, dev->irq, stu300_irh, 0, NAME, dev);
+	if (ret < 0)
+		return ret;
 
 	dev->speed = scl_frequency;
 
 	clk_enable(dev->clk);
 	ret = stu300_init_hw(dev);
 	clk_disable(dev->clk);
-
 	if (ret != 0) {
 		dev_err(&dev->pdev->dev, "error initializing hardware.\n");
-		goto err_init_hw;
+		return -EIO;
 	}
 
 	/* IRQ event handling initialization */
@@ -952,29 +928,13 @@ stu300_probe(struct platform_device *pdev)
 	/* i2c device drivers may be active on return from add_adapter() */
 	ret = i2c_add_numbered_adapter(adap);
 	if (ret) {
-		dev_err(&dev->pdev->dev, "failure adding ST Micro DDC "
+		dev_err(&pdev->dev, "failure adding ST Micro DDC "
 		       "I2C adapter\n");
-		goto err_add_adapter;
+		return ret;
 	}
-	return 0;
 
- err_add_adapter:
- err_init_hw:
-	free_irq(dev->irq, dev);
- err_no_irq:
-	iounmap(dev->virtbase);
- err_no_ioremap:
-	release_mem_region(dev->phybase, dev->physize);
- err_no_ioregion:
-	platform_set_drvdata(pdev, NULL);
- err_no_resource:
-	clk_put(dev->clk);
- err_no_clk:
-	kfree(dev);
- err_no_devmem:
-	dev_err(&pdev->dev, "failed to add " NAME " adapter: %d\n",
-		pdev->id);
-	return ret;
+	platform_set_drvdata(pdev, dev);
+	return 0;
 }
 
 #ifdef CONFIG_PM
@@ -1013,12 +973,7 @@ stu300_remove(struct platform_device *pdev)
 	i2c_del_adapter(&dev->adapter);
 	/* Turn off everything */
 	stu300_wr8(0x00, dev->virtbase + I2C_CR);
-	free_irq(dev->irq, dev);
-	iounmap(dev->virtbase);
-	release_mem_region(dev->phybase, dev->physize);
-	clk_put(dev->clk);
 	platform_set_drvdata(pdev, NULL);
-	kfree(dev);
 	return 0;
 }
 
-- 
1.7.7.6

Re: [PATCH] i2c: stu300: use devm managed resources

[Wolfram Sang]

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On Sat, Jul 14, 2012 at 11:23:13PM +0200, Linus Walleij wrote:
> Allocate memory for device state using devm_kzalloc(), get the
> clock using devm_clk_get(), get the IRQ using devm_request_irq(),
> request and remap memory using devm_request_and_ioremap().
> All to simplify accounting and letting the kernel do the
> garbage-collection.
> 
> Signed-off-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
> ChangeLog v2->v3:
> - Also delete the cached physical base and size from the state
>   holder struct.
> ChangeLog v1->v2:
> - Use more devm* stuff, at Wolfram's request.
> - Note: based on a clean v3.5-rc6, may need some patch -p1 < patch
>   to apply on the i2c tree, if you want me to rebase it, just tell
>   me where to find the baseline.

I can't apply this on top of your clk_prepare/unprepare patch. I tried
to fix it but was unsure how to handle the clk_unprepare in the error
path of probe. Could you fix it? (BTW as mentioned before, my next
branch is here: git://git.pengutronix.de/git/wsa/linux.git
i2c-embedded/for-next)

Thanks,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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