mail archive of the barebox mailing list
 help / color / mirror / Atom feed
* [PATCH 1/7] driver: introduce less error-prone dev_get_drvdata alternative
@ 2020-09-28 15:42 Ahmad Fatoum
  2020-09-28 15:42 ` [PATCH 2/7] led: pca955x: fix probing from device tree Ahmad Fatoum
                   ` (8 more replies)
  0 siblings, 9 replies; 20+ messages in thread
From: Ahmad Fatoum @ 2020-09-28 15:42 UTC (permalink / raw)
  To: barebox; +Cc: Ahmad Fatoum

We use dev_get_drvdata to get the driver match data associated with a
device. This has two shortcomings:

 - Linux has dev_get_drvdata too, which returns a private pointer for
   driver specific info to associate with a device. We use dev->priv
   (or more often container_of) for that in barebox instead

 - It nearly always involves a cast to a double pointer, which is
   error-prone as size and alignment match need to be ensured
   on the programmer's part and can easily be gotten wrong:
	enum dev_type type
	dev_get_drvdata(dev, (const void **)&type);

Add a new function that instead of using a double pointer argument,
returns the pointer directly:

 - For normal pointer driver data, no cast is necessary
 - For integer driver data casted to a pointer for storage,
   the cast is still necessary, but

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/base/driver.c | 11 +++++++++++
 include/driver.h      | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 412db6c40699..3205bbc3c33b 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -500,3 +500,14 @@ int dev_get_drvdata(struct device_d *dev, const void **data)
 
 	return -ENODEV;
 }
+
+const void *device_get_match_data(struct device_d *dev)
+{
+	if (dev->of_id_entry)
+		return dev->of_id_entry->data;
+
+	if (dev->id_entry)
+		return (void *)dev->id_entry->driver_data;
+
+	return NULL;
+}
diff --git a/include/driver.h b/include/driver.h
index 154525e0fde7..14220431f2d6 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -534,8 +534,26 @@ int devfs_create_partitions(const char *devname,
 #define DRV_OF_COMPAT(compat) \
 	IS_ENABLED(CONFIG_OFDEVICE) ? (compat) : NULL
 
+/**
+ * dev_get_drvdata - get driver match data associated with device
+ * @dev: device instance
+ * @data: pointer to void *, where match data is stored
+ *
+ * Returns 0 on success and error code otherwise.
+ *
+ * DEPRECATED: use device_get_match_data instead, which avoids
+ * common pitfalls due to explicit pointer casts
+ */
 int dev_get_drvdata(struct device_d *dev, const void **data);
 
+/**
+ * device_get_match_data - get driver match data associated with device
+ * @dev: device instance
+ *
+ * Returns match data on success and NULL otherwise
+ */
+const void *device_get_match_data(struct device_d *dev);
+
 int device_match_of_modalias(struct device_d *dev, struct driver_d *drv);
 
 #endif /* DRIVER_H */
-- 
2.28.0


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

^ permalink raw reply	[flat|nested] 20+ messages in thread

end of thread, other threads:[~2020-10-07  8:43 UTC | newest]

Thread overview: 20+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-28 15:42 [PATCH 1/7] driver: introduce less error-prone dev_get_drvdata alternative Ahmad Fatoum
2020-09-28 15:42 ` [PATCH 2/7] led: pca955x: fix probing from device tree Ahmad Fatoum
2020-09-29  7:19   ` Sascha Hauer
2020-09-30  7:28     ` Ahmad Fatoum
2020-09-28 15:42 ` [PATCH 3/7] dma: apbh: fix out-of-bounds write on 64-bit SoCs Ahmad Fatoum
2020-09-28 15:42 ` [PATCH 4/7] aiodev: lm75: " Ahmad Fatoum
2020-09-28 15:42 ` [PATCH 5/7] mtd: nand-mxs: " Ahmad Fatoum
2020-09-28 16:01   ` Marco Felsch
2020-09-28 16:03     ` Ahmad Fatoum
2020-09-28 16:08       ` Marco Felsch
2020-09-28 15:42 ` [PATCH 6/7] video: imx-hdmi: fix dev_get_drvdata misuse Ahmad Fatoum
2020-09-28 15:42 ` [PATCH 7/7] driver: migrate some from dev_get_drvdata to device_get_match_data Ahmad Fatoum
2020-09-28 15:46 ` [PATCH 1/7] driver: introduce less error-prone dev_get_drvdata alternative Ahmad Fatoum
2020-09-29  6:45 ` Sascha Hauer
2020-09-29  7:32 ` Sascha Hauer
2020-09-29  9:42   ` Ahmad Fatoum
2020-09-30  7:48     ` Sascha Hauer
2020-09-30 13:13       ` Ahmad Fatoum
2020-10-05  8:31         ` Ahmad Fatoum
2020-10-07  8:43           ` Sascha Hauer

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox