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Message-Id: <20130114141422.80D6D3E232D@localhost>
Date: Mon, 14 Jan 2013 14:14:22 +0000
From: Grant Likely <grant.likely@...retlab.ca>
To: Tony Prisk <linux@...sktech.co.nz>,
Linux Walleij <linus.walleij@...aro.org>
Cc: vt8500-wm8505-linux-kernel@...glegroups.com,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux@....linux.org.uk, Tony Prisk <linux@...sktech.co.nz>
Subject: Re: [PATCH v2] gpio: vt8500: memory cleanup missing
On Fri, 11 Jan 2013 08:09:46 +1300, Tony Prisk <linux@...sktech.co.nz> wrote:
> This driver is missing a .remove callback, and the fail path on
> probe is incomplete.
>
> If an error occurs in vt8500_add_chips, gpio_base is not unmapped.
> The driver is also ignoring the return value from this function so
> if a chip fails to register it completes as successful.
>
> Replaced pr_err with dev_err in vt8500_add_chips since the device is
> available.
>
> There is also no .remove callback defined. To allow removing the
> registered chips, I have moved *vtchip to be a static global.
>
> Signed-off-by: Tony Prisk <linux@...sktech.co.nz>
> ---
> v2:
> Remove global variable and use platform_set_drvdata instead.
>
> drivers/gpio/gpio-vt8500.c | 51 +++++++++++++++++++++++++++++++++++---------
> 1 file changed, 41 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpio/gpio-vt8500.c b/drivers/gpio/gpio-vt8500.c
> index b53320a..87e59b5 100644
> --- a/drivers/gpio/gpio-vt8500.c
> +++ b/drivers/gpio/gpio-vt8500.c
> @@ -233,10 +233,12 @@ static int vt8500_add_chips(struct platform_device *pdev, void __iomem *base,
> sizeof(struct vt8500_gpio_chip) * data->num_banks,
> GFP_KERNEL);
> if (!vtchip) {
> - pr_err("%s: failed to allocate chip memory\n", __func__);
> + dev_err(&pdev->dev, "failed to allocate chip memory\n");
> return -ENOMEM;
> }
>
> + platform_set_drvdata(pdev, vtchip);
> +
> for (i = 0; i < data->num_banks; i++) {
> vtchip[i].base = base;
> vtchip[i].regs = &data->banks[i];
> @@ -261,6 +263,7 @@ static int vt8500_add_chips(struct platform_device *pdev, void __iomem *base,
>
> gpiochip_add(chip);
> }
> +
> return 0;
> }
>
Watch out; irrelevant whitespace change here. From a maintainer point of
voiew, I'm less confident about a patch when I see unrelated whitespace
changes because it suggests that there are things in the patch that you
don't intend. It helps me out a lot if this stuff gets scrubbed before I
see it.
> @@ -273,36 +276,64 @@ static struct of_device_id vt8500_gpio_dt_ids[] = {
>
> static int vt8500_gpio_probe(struct platform_device *pdev)
> {
> + int ret;
> void __iomem *gpio_base;
> - struct device_node *np;
> + struct device_node *np = pdev->dev.of_node;
> const struct of_device_id *of_id =
> of_match_device(vt8500_gpio_dt_ids, &pdev->dev);
>
> - if (!of_id) {
> - dev_err(&pdev->dev, "Failed to find gpio controller\n");
> + if (!np) {
> + dev_err(&pdev->dev, "GPIO node missing in devicetree\n");
> return -ENODEV;
> }
>
> - np = pdev->dev.of_node;
> - if (!np) {
> - dev_err(&pdev->dev, "Missing GPIO description in devicetree\n");
> - return -EFAULT;
> + if (!of_id) {
> + dev_err(&pdev->dev, "No matching driver data\n");
> + return -ENODEV;
> }
Why is this flipped around? I don't see any functional reason for this
change.
In actual fact, since the driver needs both it only needs to test for
the of_id. If there is no node, then of_id will never be set.
>
> gpio_base = of_iomap(np, 0);
> if (!gpio_base) {
> dev_err(&pdev->dev, "Unable to map GPIO registers\n");
> - of_node_put(np);
> return -ENOMEM;
> }
>
> - vt8500_add_chips(pdev, gpio_base, of_id->data);
> + ret = vt8500_add_chips(pdev, gpio_base, of_id->data);
> + if (ret) {
> + iounmap(gpio_base);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int vt8500_gpio_remove(struct platform_device *pdev)
> +{
> + int i;
> + int ret;
> + const struct vt8500_gpio_data *data;
> + struct vt8500_gpio_chip *vtchip = platform_get_drvdata(pdev);
> + void __iomem *gpio_base = vtchip[0].base;
> + const struct of_device_id *of_id =
> + of_match_device(vt8500_gpio_dt_ids, &pdev->dev);
> +
> + data = of_id->data;
> +
> + for (i = 0; i < data->num_banks; i++) {
It would make for simpler code all around if num_banks was cached in the
vt8500_gpio_chip structure during the .probe() routine. It looks wrong
to be calling of_match_device() in the remove hook.
Otherwise this iteration looks much better.
g.
> + ret = gpiochip_remove(&vtchip[i].chip);
> + if (ret)
> + dev_warn(&pdev->dev, "gpiochip_remove returned %d\n",
> + ret);
> + }
> +
> + iounmap(gpio_base);
>
> return 0;
> }
>
> static struct platform_driver vt8500_gpio_driver = {
> .probe = vt8500_gpio_probe,
> + .remove = vt8500_gpio_remove,
> .driver = {
> .name = "vt8500-gpio",
> .owner = THIS_MODULE,
> --
> 1.7.9.5
>
> --
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--
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.
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