mtd: spi-nor: add initial sysfs support

Add support to show the manufacturer, the partname and JEDEC identifier
as well as to dump the SFDP table. Not all flashes list their SFDP table
contents in their datasheet. So having that is useful. It might also be
helpful in bug reports from users.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Acked-by: Pratyush Yadav <p.yadav@ti.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor b/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
new file mode 100644 (file)
index 0000000..d76cd39
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
@@ -0,0 +1,31 @@
+What:          /sys/bus/spi/devices/.../spi-nor/jedec_id
+Date:          April 2021
+KernelVersion: 5.14
+Contact:       linux-mtd@lists.infradead.org
+Description:   (RO) The JEDEC ID of the SPI NOR flash as reported by the
+               flash device.
+
+
+What:          /sys/bus/spi/devices/.../spi-nor/manufacturer
+Date:          April 2021
+KernelVersion: 5.14
+Contact:       linux-mtd@lists.infradead.org
+Description:   (RO) Manufacturer of the SPI NOR flash.
+
+
+What:          /sys/bus/spi/devices/.../spi-nor/partname
+Date:          April 2021
+KernelVersion: 5.14
+Contact:       linux-mtd@lists.infradead.org
+Description:   (RO) Part name of the SPI NOR flash.
+
+
+What:          /sys/bus/spi/devices/.../spi-nor/sfdp
+Date:          April 2021
+KernelVersion: 5.14
+Contact:       linux-mtd@lists.infradead.org
+Description:   (RO) This attribute is only present if the SPI NOR flash
+               device supports the "Read SFDP" command (5Ah).
+
+               If present, it contains the complete SFDP (serial flash
+               discoverable parameters) binary data of the flash.

diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index 136f245c91dcec17598e7c6d1fc65ac5087eb905..6b904e43937289c1e6118f8a9a9ab4c877d88dc8 100644 (file)
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-spi-nor-objs                   := core.o sfdp.o swp.o otp.o
+spi-nor-objs                   := core.o sfdp.o swp.o otp.o sysfs.o
 spi-nor-objs                   += atmel.o
 spi-nor-objs                   += catalyst.o
 spi-nor-objs                   += eon.o

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index a21b0085de054b88aa609d030519a014672ac70a..970ed6e3f3ba911f4c0bf9be3f8b04765020f0b5 100644 (file)
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3459,6 +3459,7 @@ static struct spi_mem_driver spi_nor_driver = {
                .driver = {
                        .name = "spi-nor",
                        .of_match_table = spi_nor_of_table,
+                       .dev_groups = spi_nor_sysfs_groups,
                },
                .id_table = spi_nor_dev_ids,
        },

diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index f6dc28091c6d5a6e952c2ba24d50b57e5621f83b..3348e1dd14452604693c483ba9683bf9f6d7c49a 100644 (file)
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -490,6 +490,8 @@ extern const struct spi_nor_manufacturer spi_nor_winbond;
 extern const struct spi_nor_manufacturer spi_nor_xilinx;
 extern const struct spi_nor_manufacturer spi_nor_xmc;
 
+extern const struct attribute_group *spi_nor_sysfs_groups[];
+
 void spi_nor_spimem_setup_op(const struct spi_nor *nor,
                             struct spi_mem_op *op,
                             const enum spi_nor_protocol proto);

diff --git a/drivers/mtd/spi-nor/sysfs.c b/drivers/mtd/spi-nor/sysfs.c
new file mode 100644 (file)
index 0000000..9aec9d8
--- /dev/null
+++ b/drivers/mtd/spi-nor/sysfs.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/mtd/spi-nor.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+#include <linux/sysfs.h>
+
+#include "core.h"
+
+static ssize_t manufacturer_show(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct spi_mem *spimem = spi_get_drvdata(spi);
+       struct spi_nor *nor = spi_mem_get_drvdata(spimem);
+
+       return sysfs_emit(buf, "%s\n", nor->manufacturer->name);
+}
+static DEVICE_ATTR_RO(manufacturer);
+
+static ssize_t partname_show(struct device *dev,
+                            struct device_attribute *attr, char *buf)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct spi_mem *spimem = spi_get_drvdata(spi);
+       struct spi_nor *nor = spi_mem_get_drvdata(spimem);
+
+       return sysfs_emit(buf, "%s\n", nor->info->name);
+}
+static DEVICE_ATTR_RO(partname);
+
+static ssize_t jedec_id_show(struct device *dev,
+                            struct device_attribute *attr, char *buf)
+{
+       struct spi_device *spi = to_spi_device(dev);
+       struct spi_mem *spimem = spi_get_drvdata(spi);
+       struct spi_nor *nor = spi_mem_get_drvdata(spimem);
+
+       return sysfs_emit(buf, "%*phN\n", nor->info->id_len, nor->info->id);
+}
+static DEVICE_ATTR_RO(jedec_id);
+
+static struct attribute *spi_nor_sysfs_entries[] = {
+       &dev_attr_manufacturer.attr,
+       &dev_attr_partname.attr,
+       &dev_attr_jedec_id.attr,
+       NULL
+};
+
+static ssize_t sfdp_read(struct file *filp, struct kobject *kobj,
+                        struct bin_attribute *bin_attr, char *buf,
+                        loff_t off, size_t count)
+{
+       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);
+       struct sfdp *sfdp = nor->sfdp;
+       size_t sfdp_size = sfdp->num_dwords * sizeof(*sfdp->dwords);
+
+       return memory_read_from_buffer(buf, count, &off, nor->sfdp->dwords,
+                                      sfdp_size);
+}
+static BIN_ATTR_RO(sfdp, 0);
+
+static struct bin_attribute *spi_nor_sysfs_bin_entries[] = {
+       &bin_attr_sfdp,
+       NULL
+};
+
+static umode_t spi_nor_sysfs_is_bin_visible(struct kobject *kobj,
+                                           struct bin_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 == &bin_attr_sfdp && nor->sfdp)
+               return 0444;
+
+       return 0;
+}
+
+static const struct attribute_group spi_nor_sysfs_group = {
+       .name           = "spi-nor",
+       .is_bin_visible = spi_nor_sysfs_is_bin_visible,
+       .attrs          = spi_nor_sysfs_entries,
+       .bin_attrs      = spi_nor_sysfs_bin_entries,
+};
+
+const struct attribute_group *spi_nor_sysfs_groups[] = {
+       &spi_nor_sysfs_group,
+       NULL
+};