[PATCH v2 2/2] mtd: spi-nor: add initial sysfs support

[Heiko Thiery]

Hi Michael,

Am Di., 23. März 2021 um 15:34 Uhr schrieb Michael Walle <michael at walle.cc>:
>
> Add support to show the name 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 at walle.cc>

Tested-by: Heiko Thiery <heiko.thiery at gmail.com>

> ---
>  drivers/mtd/spi-nor/Makefile |  2 +-
>  drivers/mtd/spi-nor/core.c   |  5 +++
>  drivers/mtd/spi-nor/core.h   |  3 ++
>  drivers/mtd/spi-nor/sysfs.c  | 86 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 95 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/mtd/spi-nor/sysfs.c
>
> diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
> index 653923896205..aff308f75987 100644
> --- 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
> +spi-nor-objs                   := core.o sfdp.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 fbc34158a883..02523ddac612 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -3708,6 +3708,10 @@ static int spi_nor_probe(struct spi_mem *spimem)
>         if (ret)
>                 return ret;
>
> +       ret = spi_nor_sysfs_create(nor);
> +       if (ret)
> +               return ret;
> +
>         return mtd_device_register(&nor->mtd, data ? data->parts : NULL,
>                                    data ? data->nr_parts : 0);
>  }
> @@ -3717,6 +3721,7 @@ static int spi_nor_remove(struct spi_mem *spimem)
>         struct spi_nor *nor = spi_mem_get_drvdata(spimem);
>
>         spi_nor_restore(nor);
> +       spi_nor_sysfs_remove(nor);
>
>         /* Clean up MTD stuff. */
>         return mtd_device_unregister(&nor->mtd);
> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> index 08d2469837da..599035200a03 100644
> --- a/drivers/mtd/spi-nor/core.h
> +++ b/drivers/mtd/spi-nor/core.h
> @@ -486,4 +486,7 @@ static struct spi_nor __maybe_unused *mtd_to_spi_nor(struct mtd_info *mtd)
>         return mtd->priv;
>  }
>
> +int spi_nor_sysfs_create(struct spi_nor *nor);
> +void spi_nor_sysfs_remove(struct spi_nor *nor);
> +
>  #endif /* __LINUX_MTD_SPI_NOR_INTERNAL_H */
> diff --git a/drivers/mtd/spi-nor/sysfs.c b/drivers/mtd/spi-nor/sysfs.c
> new file mode 100644
> index 000000000000..c62cc4d6bce6
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/sysfs.c
> @@ -0,0 +1,86 @@
> +// 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 name_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(name);
> +
> +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_name.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 0;
> +
> +       return 0444;
> +}
> +
> +static struct attribute_group spi_nor_sysfs_attr_group = {
> +       .name           = NULL,
> +       .is_bin_visible = spi_nor_sysfs_is_bin_visible,
> +       .attrs          = spi_nor_sysfs_entries,
> +       .bin_attrs      = spi_nor_sysfs_bin_entries,
> +};
> +
> +int spi_nor_sysfs_create(struct spi_nor *nor)
> +{
> +       return sysfs_create_group(&nor->dev->kobj, &spi_nor_sysfs_attr_group);
> +}
> +
> +void spi_nor_sysfs_remove(struct spi_nor *nor)
> +{
> +       sysfs_remove_group(&nor->dev->kobj, &spi_nor_sysfs_attr_group);
> +}
> --
> 2.20.1
>
>
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Thank you!