On Fri, 4 Feb 2011 18:39:13 -0800
Andres Salomon <dilinger@xxxxxxxxxx> wrote:
> On Thu, 3 Feb 2011 09:31:54 +0000
> Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> > On Wed, Feb 02, 2011 at 11:03:26PM -0800, Andres Salomon wrote:
> > > Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> wrote:
> >
> > > > Then they are doing it incorrectly. One possible way is to have
> > > > parent device carry relevant data in its drvdata and have
> > > > children get it from there.
> >
> > > I believe some drivers are even using the parent device already.
> > > See drivers/leds/leds-mc13783.c, for example, whose parent device
> > > drvdata is used to pass around a struct mc13783 to its children.
> > > Sounds like a possibility, will need to look into it further.
> >
> > That's the current best practice approach.
>
[rambling]
> Even that would require the weird API of mfd_add_devices needing to be
> passed the type of what's pointed to by the parent's drvdata.
>
Actually, how about something like the following? This would leave
drvdata unaffected.
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index d83ad0f..a324a83 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -25,6 +25,7 @@ static int mfd_add_device(struct device *parent, int id,
{
struct resource *res;
struct platform_device *pdev;
+ struct mfd_platform_data pdata = { NULL, NULL };
int ret = -ENOMEM;
int r;
@@ -39,12 +40,18 @@ static int mfd_add_device(struct device *parent, int id,
pdev->dev.parent = parent;
platform_set_drvdata(pdev, cell->driver_data);
+ pdata.cell = cell;
if (cell->data_size) {
- ret = platform_device_add_data(pdev,
- cell->platform_data, cell->data_size);
- if (ret)
+ pdata.platform_data = kmemdup(cell->platform_data,
+ cell->data_size, GFP_KERNEL);
+ if (!pdata.platform_data) {
+ ret = -ENOMEM;
goto fail_res;
+ }
}
+ ret = platform_device_add_data(pdev, &pdata, sizeof(pdata));
+ if (ret)
+ goto fail_pdata;
for (r = 0; r < cell->num_resources; r++) {
res[r].name = cell->resources[r].name;
@@ -91,6 +98,9 @@ static int mfd_add_device(struct device *parent, int id,
return 0;
/* platform_device_del(pdev); */
+fail_pdata:
+ if (pdata.platform_data)
+ kfree(pdata.platform_data);
fail_res:
kfree(res);
fail_device:
@@ -122,6 +132,7 @@ EXPORT_SYMBOL(mfd_add_devices);
static int mfd_remove_devices_fn(struct device *dev, void *unused)
{
+ /* TODO: nuke pdata memory */
platform_device_unregister(to_platform_device(dev));
return 0;
}
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index 835996e..dbc52a2 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -55,6 +55,26 @@ struct mfd_cell {
bool pm_runtime_no_callbacks;
};
+/* simple wrapper for a platform device's pdata */
+struct mfd_platform_data {
+ void *platform_data;
+ struct mfd_cell *cell;
+};
+
+/*
+ * Given a platform device that's been created by mfd_add_devices(), fetch
+ * the mfd_cell that created it.
+ */
+static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev)
+{
+ return ((struct mfd_platform_data *)pdev->dev.platform_data)->cell;
+}
+
+static inline void *mfd_platform_data(struct platform_device *pdev)
+{
+ return ((struct mfd_platform_data *)pdev->dev.platform_data)->data;
+}
+
extern int mfd_add_devices(struct device *parent, int id,
const struct mfd_cell *cells, int n_devs,
struct resource *mem_base,
--
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