Re: [PATCH v3 7/7] platform: Add platform_find_device_by_driver() helper
From: Robin Murphy
Date: Wed Jul 24 2019 - 06:44:59 EST
On 23/07/2019 23:18, Suzuki K Poulose wrote:
Provide a helper to lookup platform devices by matching device
driver in order to avoid drivers trying to use platform bus
internals.
FWIW, this whole drm_match_add idiom really looks like it deserves
factoring out into an of_platform_populate-style helper, but I guess
aligning those subtle little differences is a non-trivial challenge.
[and I am well aware of just how much of a big messy can of worms DRM
device probing is in general]
Cc: Eric Anholt <eric@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Heiko StÃbner" <heiko@xxxxxxxxx>
Cc: Inki Dae <inki.dae@xxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Sandy Huang <hjc@xxxxxxxxxxxxxx>
Cc: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
drivers/base/platform.c | 14 ++++++++++++++
drivers/gpu/drm/exynos/exynos_drm_drv.c | 9 +++------
drivers/gpu/drm/mcde/mcde_drv.c | 3 +--
drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 3 +--
drivers/gpu/drm/vc4/vc4_drv.c | 3 +--
include/linux/platform_device.h | 3 +++
6 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 506a0175a5a7..a174ce5ea17c 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1197,6 +1197,20 @@ struct bus_type platform_bus_type = {
};
EXPORT_SYMBOL_GPL(platform_bus_type);
+/**
+ * platform_find_device_by_driver - Find a platform device with a given
Nit: "with" is easy to misinterpret there - my initial reaction to
looking at this was "so why not just use driver_find_device()?". Maybe
"which would match" might make it a bit clearer?
Robin.
+ * driver.
+ * @start: The device to start the search from.
+ * @drv: The device driver to look for.
+ */
+struct device *platform_find_device_by_driver(struct device *start,
+ const struct device_driver *drv)
+{
+ return bus_find_device(&platform_bus_type, start, drv,
+ (void *)platform_match);
+}
+EXPORT_SYMBOL_GPL(platform_find_device_by_driver);
+
int __init platform_bus_init(void)
{
int error;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
index 58baf49d9926..badab94be2d6 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -242,9 +242,7 @@ static struct component_match *exynos_drm_match_add(struct device *dev)
if (!info->driver || !(info->flags & DRM_COMPONENT_DRIVER))
continue;
- while ((d = bus_find_device(&platform_bus_type, p,
- &info->driver->driver,
- (void *)platform_bus_type.match))) {
+ while ((d = platform_find_device_by_driver(p, &info->driver->driver))) {
put_device(p);
if (!(info->flags & DRM_FIMC_DEVICE) ||
@@ -412,9 +410,8 @@ static void exynos_drm_unregister_devices(void)
if (!info->driver || !(info->flags & DRM_VIRTUAL_DEVICE))
continue;
- while ((dev = bus_find_device(&platform_bus_type, NULL,
- &info->driver->driver,
- (void *)platform_bus_type.match))) {
+ while ((dev = platform_find_device_by_driver(NULL,
+ &info->driver->driver))) {
put_device(dev);
platform_device_unregister(to_platform_device(dev));
}
diff --git a/drivers/gpu/drm/mcde/mcde_drv.c b/drivers/gpu/drm/mcde/mcde_drv.c
index baf63fb6850a..c07abf9e201c 100644
--- a/drivers/gpu/drm/mcde/mcde_drv.c
+++ b/drivers/gpu/drm/mcde/mcde_drv.c
@@ -477,8 +477,7 @@ static int mcde_probe(struct platform_device *pdev)
struct device_driver *drv = &mcde_component_drivers[i]->driver;
struct device *p = NULL, *d;
- while ((d = bus_find_device(&platform_bus_type, p, drv,
- (void *)platform_bus_type.match))) {
+ while ((d = platform_find_device_by_driver(p, drv))) {
put_device(p);
component_match_add(dev, &match, mcde_compare_dev, d);
p = d;
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
index 53d2c5bd61dc..38dc26376961 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
@@ -330,8 +330,7 @@ static struct component_match *rockchip_drm_match_add(struct device *dev)
struct device *p = NULL, *d;
do {
- d = bus_find_device(&platform_bus_type, p, &drv->driver,
- (void *)platform_bus_type.match);
+ d = platform_find_device_by_driver(p, &drv->driver);
put_device(p);
p = d;
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index bf11930e40e1..1551c8253bec 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -237,8 +237,7 @@ static void vc4_match_add_drivers(struct device *dev,
struct device_driver *drv = &drivers[i]->driver;
struct device *p = NULL, *d;
- while ((d = bus_find_device(&platform_bus_type, p, drv,
- (void *)platform_bus_type.match))) {
+ while ((d = platform_find_device_by_driver(p, drv))) {
put_device(p);
component_match_add(dev, match, compare_dev, d);
p = d;
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 9bc36b589827..37e15a935a42 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -51,6 +51,9 @@ extern struct device platform_bus;
extern void arch_setup_pdev_archdata(struct platform_device *);
extern struct resource *platform_get_resource(struct platform_device *,
unsigned int, unsigned int);
+extern struct device *
+platform_find_device_by_driver(struct device *start,
+ const struct device_driver *drv);
extern void __iomem *
devm_platform_ioremap_resource(struct platform_device *pdev,
unsigned int index);