On Fri, 4 Feb 2011 18:39:13 -0800 Andres Salomon dilinger@queued.net wrote:
On Thu, 3 Feb 2011 09:31:54 +0000 Mark Brown broonie@opensource.wolfsonmicro.com wrote:
On Wed, Feb 02, 2011 at 11:03:26PM -0800, Andres Salomon wrote:
Dmitry Torokhov dmitry.torokhov@gmail.com 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,