mtd: m25p80: bind to "nor-jedec" ID, for auto-detection

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=1103b8517041b08286cae0da8481bef9164c961a
Commit:     1103b8517041b08286cae0da8481bef9164c961a
Parent:     8ff16cf77ce314c20d7bd57c788f5b7719b450e1
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Fri Mar 27 10:29:50 2015 -0700
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Sun Apr 5 18:56:21 2015 -0700

    mtd: m25p80: bind to "nor-jedec" ID, for auto-detection
    
    Use the new 'nor-jedec' binding to provide automatic detection of flash
    that use the 0x9F READ ID opcode. This can help for use cases where
    platforms just specify compatibility with "m25p80", and then see
    messages like this:
    
      m25p80 spi32766.0: found s25fl256s1, expected m25p80
    
    Instead, they can just specify the generic string and see this:
    
      m25p80 spi32766.0: s25fl256s1 (32768 Kbytes)
    
    Also, update the language about m25p_ids[] to straighten out the
    expectations here. We should no longer need to continuously grow the
    m25p_ids[] table, and in fact, we might want to start removing entries
    which are not used in device trees so far, so we can just default to
    auto-detection as much as possible in the future.
    
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
    Cc: Rafał Miłecki <zajec5 at gmail.com>
---
 drivers/mtd/devices/m25p80.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 85e35467..7c8b169 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -223,6 +223,8 @@ static int m25p_probe(struct spi_device *spi)
 	 */
 	if (data && data->type)
 		flash_name = data->type;
+	else if (!strcmp(spi->modalias, "nor-jedec"))
+		flash_name = NULL; /* auto-detect */
 	else
 		flash_name = spi->modalias;
 
@@ -247,9 +249,16 @@ static int m25p_remove(struct spi_device *spi)
 }
 
 /*
- * XXX This needs to be kept in sync with spi_nor_ids.  We can't share
- * it with spi-nor, because if this is built as a module then modpost
- * won't be able to read it and add appropriate aliases.
+ * Do NOT add to this array without reading the following:
+ *
+ * Historically, many flash devices are bound to this driver by their name. But
+ * since most of these flash are compatible to some extent, and their
+ * differences can often be differentiated by the JEDEC read-ID command, we
+ * encourage new users to add support to the spi-nor library, and simply bind
+ * against a generic string here (e.g., "nor-jedec").
+ *
+ * Many flash names are kept here in this list (as well as in spi-nor.c) to
+ * keep them available as module aliases for existing platforms.
  */
 static const struct spi_device_id m25p_ids[] = {
 	{"at25fs010"},	{"at25fs040"},	{"at25df041a"},	{"at25df321a"},
@@ -291,6 +300,12 @@ static const struct spi_device_id m25p_ids[] = {
 	{"w25x64"},	{"w25q64"},	{"w25q80"},	{"w25q80bl"},
 	{"w25q128"},	{"w25q256"},	{"cat25c11"},
 	{"cat25c03"},	{"cat25c09"},	{"cat25c17"},	{"cat25128"},
+
+	/*
+	 * Generic support for SPI NOR that can be identified by the JEDEC READ
+	 * ID opcode (0x9F). Use this, if possible.
+	 */
+	{"nor-jedec"},
 	{ },
 };
 MODULE_DEVICE_TABLE(spi, m25p_ids);