* Platform data from devicetree
@ 2012-08-08 23:06 Tony Prisk
2012-08-08 23:23 ` Rob Herring
0 siblings, 1 reply; 3+ messages in thread
From: Tony Prisk @ 2012-08-08 23:06 UTC (permalink / raw)
To: linux-arm-kernel
Quick question regarding platform_devices created from devicetree.
At the moment, we do a of_match_device() against vt8500_gpio_dt_ids[] to
get an of_device_id that contains the .data field to pass into the
driver.
Given that pdev is created from a match against vt8500_gpio_dt_ids[] as
well, why does pdev->dev.of_node.data == NULL? Is this data not
populated into this field? What data can be passed into this field?
Regards
Tony Prisk
Example code below:
static struct of_device_id vt8500_gpio_dt_ids[] = {
{ .compatible = "via,vt8500-gpio", .data = &vt8500_data, },
{ .compatible = "wm,wm8505-gpio", .data = &wm8505_data, },
{ .compatible = "wm,wm8650-gpio", .data = &wm8650_data, },
{ /* Sentinel */ },
};
static int __devinit vt8500_gpio_probe(struct platform_device *pdev)
{
void __iomem *gpio_base;
struct device_node *np;
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");
return -ENODEV;
}
np = pdev->dev.of_node;
...
}
static struct platform_driver vt8500_gpio_driver = {
.probe = vt8500_gpio_probe,
.driver = {
.name = "vt8500-gpio",
.owner = THIS_MODULE,
.of_match_table = vt8500_gpio_dt_ids,
},
};
^ permalink raw reply [flat|nested] 3+ messages in thread* Platform data from devicetree
2012-08-08 23:06 Platform data from devicetree Tony Prisk
@ 2012-08-08 23:23 ` Rob Herring
2012-08-09 0:35 ` Tony Prisk
0 siblings, 1 reply; 3+ messages in thread
From: Rob Herring @ 2012-08-08 23:23 UTC (permalink / raw)
To: linux-arm-kernel
On 08/08/2012 06:06 PM, Tony Prisk wrote:
> Quick question regarding platform_devices created from devicetree.
>
> At the moment, we do a of_match_device() against vt8500_gpio_dt_ids[] to
> get an of_device_id that contains the .data field to pass into the
> driver.
>
> Given that pdev is created from a match against vt8500_gpio_dt_ids[] as
> well, why does pdev->dev.of_node.data == NULL? Is this data not
> populated into this field? What data can be passed into this field?
>
This commit may be why:
commit b1608d69cb804e414d0887140ba08a9398e4e638
Author: Grant Likely <grant.likely@secretlab.ca>
Date: Wed May 18 11:19:24 2011 -0600
drivercore: revert addition of of_match to struct device
Commit b826291c, "drivercore/dt: add a match table pointer to struct
device" added an of_match pointer to struct device to cache the
of_match_table entry discovered at driver match time. This was unsafe
because matching is not an atomic operation with probing a driver. If
two or more drivers are attempted to be matched to a driver at the
same time, then the cached matching entry pointer could get
overwritten.
This patch reverts the of_match cache pointer and reworks all users to
call of_match_device() directly instead.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
> Regards
>
> Tony Prisk
>
>
> Example code below:
>
> static struct of_device_id vt8500_gpio_dt_ids[] = {
> { .compatible = "via,vt8500-gpio", .data = &vt8500_data, },
> { .compatible = "wm,wm8505-gpio", .data = &wm8505_data, },
> { .compatible = "wm,wm8650-gpio", .data = &wm8650_data, },
> { /* Sentinel */ },
> };
>
> static int __devinit vt8500_gpio_probe(struct platform_device *pdev)
> {
> void __iomem *gpio_base;
> struct device_node *np;
> 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");
> return -ENODEV;
> }
>
> np = pdev->dev.of_node;
> ...
> }
>
> static struct platform_driver vt8500_gpio_driver = {
> .probe = vt8500_gpio_probe,
> .driver = {
> .name = "vt8500-gpio",
> .owner = THIS_MODULE,
> .of_match_table = vt8500_gpio_dt_ids,
> },
> };
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Platform data from devicetree
2012-08-08 23:23 ` Rob Herring
@ 2012-08-09 0:35 ` Tony Prisk
0 siblings, 0 replies; 3+ messages in thread
From: Tony Prisk @ 2012-08-09 0:35 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, 2012-08-08 at 18:23 -0500, Rob Herring wrote:
> On 08/08/2012 06:06 PM, Tony Prisk wrote:
> > Quick question regarding platform_devices created from devicetree.
> >
> > At the moment, we do a of_match_device() against vt8500_gpio_dt_ids[] to
> > get an of_device_id that contains the .data field to pass into the
> > driver.
> >
> > Given that pdev is created from a match against vt8500_gpio_dt_ids[] as
> > well, why does pdev->dev.of_node.data == NULL? Is this data not
> > populated into this field? What data can be passed into this field?
> >
>
> This commit may be why:
>
> commit b1608d69cb804e414d0887140ba08a9398e4e638
> Author: Grant Likely <grant.likely@secretlab.ca>
> Date: Wed May 18 11:19:24 2011 -0600
>
> drivercore: revert addition of of_match to struct device
>
> Commit b826291c, "drivercore/dt: add a match table pointer to struct
> device" added an of_match pointer to struct device to cache the
> of_match_table entry discovered at driver match time. This was unsafe
> because matching is not an atomic operation with probing a driver. If
> two or more drivers are attempted to be matched to a driver at the
> same time, then the cached matching entry pointer could get
> overwritten.
>
> This patch reverts the of_match cache pointer and reworks all users to
> call of_match_device() directly instead.
>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
>
>
>
> > Regards
> >
> > Tony Prisk
> >
> >
> > Example code below:
> >
> > static struct of_device_id vt8500_gpio_dt_ids[] = {
> > { .compatible = "via,vt8500-gpio", .data = &vt8500_data, },
> > { .compatible = "wm,wm8505-gpio", .data = &wm8505_data, },
> > { .compatible = "wm,wm8650-gpio", .data = &wm8650_data, },
> > { /* Sentinel */ },
> > };
> >
> > static int __devinit vt8500_gpio_probe(struct platform_device *pdev)
> > {
> > void __iomem *gpio_base;
> > struct device_node *np;
> > 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");
> > return -ENODEV;
> > }
> >
> > np = pdev->dev.of_node;
> > ...
> > }
> >
> > static struct platform_driver vt8500_gpio_driver = {
> > .probe = vt8500_gpio_probe,
> > .driver = {
> > .name = "vt8500-gpio",
> > .owner = THIS_MODULE,
> > .of_match_table = vt8500_gpio_dt_ids,
> > },
> > };
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
>
Thanks Rob.
Thought I was doing something wrong because it seemed like it should
work.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-08-08 23:06 Platform data from devicetree Tony Prisk
2012-08-08 23:23 ` Rob Herring
2012-08-09 0:35 ` Tony Prisk
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