mtd: spi-nor: hide jedec_id sysfs attribute if not present

[ Upstream commit 7d388551b6888f3725e6c957f472526b35161a5b ]

Some non-jedec compliant flashes (like the Everspin flashes) don't have
an ID at all. Hide the attribute in this case.

Fixes: 36ac02286265 ("mtd: spi-nor: add initial sysfs support")
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Link: https://lore.kernel.org/r/20220810220654.1297699-2-michael@walle.cc
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor b/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
index d76cd39..e9ef69a 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
+++ b/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
@@ -5,6 +5,9 @@ Contact:        linux-mtd@lists.infradead.org
 Description:   (RO) The JEDEC ID of the SPI NOR flash as reported by the
                flash device.
 
+               The attribute is not present if the flash doesn't support
+               the "Read JEDEC ID" command (9Fh). This is the case for
+               non-JEDEC compliant flashes.
 
 What:          /sys/bus/spi/devices/.../spi-nor/manufacturer
 Date:          April 2021

diff --git a/drivers/mtd/spi-nor/sysfs.c b/drivers/mtd/spi-nor/sysfs.c
index 9aec9d8..4c3b351 100644 (file)
--- a/drivers/mtd/spi-nor/sysfs.c
+++ b/drivers/mtd/spi-nor/sysfs.c
@@ -67,6 +67,19 @@ static struct bin_attribute *spi_nor_sysfs_bin_entries[] = {
        NULL
 };
 
+static umode_t spi_nor_sysfs_is_visible(struct kobject *kobj,
+                                       struct attribute *attr, int n)
+{
+       struct spi_device *spi = to_spi_device(kobj_to_dev(kobj));
+       struct spi_mem *spimem = spi_get_drvdata(spi);
+       struct spi_nor *nor = spi_mem_get_drvdata(spimem);
+
+       if (attr == &dev_attr_jedec_id.attr && !nor->info->id_len)
+               return 0;
+
+       return 0444;
+}
+
 static umode_t spi_nor_sysfs_is_bin_visible(struct kobject *kobj,
                                            struct bin_attribute *attr, int n)
 {
@@ -82,6 +95,7 @@ static umode_t spi_nor_sysfs_is_bin_visible(struct kobject *kobj,
 
 static const struct attribute_group spi_nor_sysfs_group = {
        .name           = "spi-nor",
+       .is_visible     = spi_nor_sysfs_is_visible,
        .is_bin_visible = spi_nor_sysfs_is_bin_visible,
        .attrs          = spi_nor_sysfs_entries,
        .bin_attrs      = spi_nor_sysfs_bin_entries,