| Message ID | 1447713292-91525-2-git-send-email-computersforpeace@gmail.com |
|---|---|
| State | Accepted |
| Commit | de57732da86288cae9a84bd6ce7cf1d1e21f8329 |
| Headers | show |
Hello Brian, On 11/16/2015 07:34 PM, Brian Norris wrote: > Commit 43163022927b ("mtd: m25p80: allow arbitrary OF matching for > "jedec,spi-nor"") moved the "jedec,spi-nor" handling from the > spi_device_id table to the of_match_table, to better handle matching > complex device tree compatible strings. With that patch, device tree > support works as expected when m25p80.c is built into the kernel. > > However, that commit ignored the fact that: > > (1) (non-DT) platform devices might want to use the "spi-nor" string > for matching with this driver, rather than picking an arbitrary one > like "m25p80" > (2) the core SPI uevent/modalias code doesn't yet support kernel module > autoloading via of_match_table strings; so for DT-based devices, it > will only report (part of) the first compatible string used > Very nice changelog message! Patch looks good to me. Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Best regards,
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c index f002a8f75374..151b453d0867 100644 --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -179,7 +179,7 @@ static int m25p_probe(struct spi_device *spi) struct m25p *flash; struct spi_nor *nor; enum read_mode mode = SPI_NOR_NORMAL; - char *flash_name = NULL; + char *flash_name; int ret; data = dev_get_platdata(&spi->dev); @@ -219,6 +219,8 @@ static int m25p_probe(struct spi_device *spi) */ if (data && data->type) flash_name = data->type; + else if (!strcmp(spi->modalias, "spi-nor")) + flash_name = NULL; /* auto-detect */ else flash_name = spi->modalias; @@ -253,6 +255,13 @@ static int m25p_remove(struct spi_device *spi) */ static const struct spi_device_id m25p_ids[] = { /* + * Allow non-DT platform devices to bind to the "spi-nor" modalias, and + * hack around the fact that the SPI core does not provide uevent + * matching for .of_match_table + */ + {"spi-nor"}, + + /* * Entries not used in DTs that should be safe to drop after replacing * them with "nor-jedec" in platform data. */
Commit 43163022927b ("mtd: m25p80: allow arbitrary OF matching for "jedec,spi-nor"") moved the "jedec,spi-nor" handling from the spi_device_id table to the of_match_table, to better handle matching complex device tree compatible strings. With that patch, device tree support works as expected when m25p80.c is built into the kernel. However, that commit ignored the fact that: (1) (non-DT) platform devices might want to use the "spi-nor" string for matching with this driver, rather than picking an arbitrary one like "m25p80" (2) the core SPI uevent/modalias code doesn't yet support kernel module autoloading via of_match_table strings; so for DT-based devices, it will only report (part of) the first compatible string used Problem (1) has been reported previously, and I forgot to patch it up afterward. Problem (2) was noticed recently here: http://lists.infradead.org/pipermail/linux-mtd/2015-October/062369.html https://lkml.org/lkml/2015/11/12/574 Specifically, this patch fixes m25p80.ko module autoloading for cases like this: flash@xxx { compatible = "jedec,spi-nor"; ... }; because modalias of "spi:spi-nor" (the only module loading info provided by the SPI core for this device) will now be listed as an alias in m25p80.ko. Notably, it does *not* help cases like this: flash@xxx { compatible = "vendor,shiny-new-device", "jedec,spi-nor"; ... }; unless we also list "shiny-new-device" in m25p_ids[]. There has been discussion on future work for this issue here: https://lkml.org/lkml/2015/11/12/574 Cc: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com> --- Tested module autoload with each of the following: compatible = "m25p80"; compatible = "jedec,spi-nor"; drivers/mtd/devices/m25p80.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)