Re: [PATCH 12/19] twl4030: mfd_cell is now implicitly available to drivers
From: Andres Salomon <hidden>
Date: 2011-02-05 03:25:41
Also in:
alsa-devel, lkml
Subsystem:
multifunction devices (mfd), the rest · Maintainers:
Lee Jones, Linus Torvalds
On Fri, 4 Feb 2011 18:39:13 -0800 Andres Salomon [off-list ref] wrote:
On Thu, 3 Feb 2011 09:31:54 +0000 Mark Brown [off-list ref] wrote:quoted
On Wed, Feb 02, 2011 at 11:03:26PM -0800, Andres Salomon wrote:quoted
Dmitry Torokhov [off-list ref] wrote:quoted
quoted
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.quoted
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,