Re: [PATCH v2, 1/1] mtd: devices: m25p80: Add PM suspend resume support

[Kamal Dasu <kamal.dasu@xxxxxxxxxxxx>]

Is everyone Ok with the latest patch ?

Kamal

On Mon, Sep 12, 2016 at 4:01 PM, Kamal Dasu <kdasu.kdev@xxxxxxxxx> wrote:
> Adding PM support so as to be able to probe spi-nor flash
> on resume. There are vendor specific commands to setup
> the transfer mode and enable read/write as part of
> spi_nor_scan(), done on initial probe and needed on resume().
> The spi-nor structure is private to the m25p driver and hence
> is the only place this can be done without having to duplicate
> code in controller driver.
>
> Signed-off-by: Kamal Dasu <kdasu.kdev@xxxxxxxxx>
> ---
>  drivers/mtd/devices/m25p80.c | 68 +++++++++++++++++++++++++++++++-------------
>  1 file changed, 48 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 9cf7fcd..48c3f64 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -186,6 +186,39 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
>  }
>
>  /*
> + * scan for spi nor flash vendor parts and setup
> + * read/write mode
> + */
> +static int m25p_nor_flash_scan(struct device *dev)
> +{
> +       struct m25p *flash = dev_get_drvdata(dev);
> +       struct flash_platform_data      *data;
> +       char *flash_name = NULL;
> +       enum read_mode mode = SPI_NOR_NORMAL;
> +
> +       data = dev_get_platdata(dev);
> +
> +       /* For some (historical?) reason many platforms provide two different
> +        * names in flash_platform_data: "name" and "type". Quite often name is
> +        * set to "m25p80" and then "type" provides a real chip name.
> +        * If that's the case, respect "type" and ignore a "name".
> +        */
> +       if (data && data->type)
> +               flash_name = data->type;
> +       else if (!strcmp(flash->spi->modalias, "spi-nor"))
> +               flash_name = NULL; /* auto-detect */
> +       else
> +               flash_name = flash->spi->modalias;
> +
> +       if (flash->spi->mode & SPI_RX_QUAD)
> +               mode = SPI_NOR_QUAD;
> +       else if (flash->spi->mode & SPI_RX_DUAL)
> +               mode = SPI_NOR_DUAL;
> +
> +       return spi_nor_scan(&flash->spi_nor, flash_name, mode);
> +}
> +
> +/*
>   * board specific setup should have ensured the SPI clock used here
>   * matches what the READ command supports, at least until this driver
>   * understands FAST_READ (for clocks over 25 MHz).
> @@ -195,8 +228,6 @@ static int m25p_probe(struct spi_device *spi)
>         struct flash_platform_data      *data;
>         struct m25p *flash;
>         struct spi_nor *nor;
> -       enum read_mode mode = SPI_NOR_NORMAL;
> -       char *flash_name;
>         int ret;
>
>         data = dev_get_platdata(&spi->dev);
> @@ -220,27 +251,11 @@ static int m25p_probe(struct spi_device *spi)
>         spi_set_drvdata(spi, flash);
>         flash->spi = spi;
>
> -       if (spi->mode & SPI_RX_QUAD)
> -               mode = SPI_NOR_QUAD;
> -       else if (spi->mode & SPI_RX_DUAL)
> -               mode = SPI_NOR_DUAL;
> -
>         if (data && data->name)
>                 nor->mtd.name = data->name;
>
> -       /* For some (historical?) reason many platforms provide two different
> -        * names in flash_platform_data: "name" and "type". Quite often name is
> -        * set to "m25p80" and then "type" provides a real chip name.
> -        * If that's the case, respect "type" and ignore a "name".
> -        */
> -       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;
> +       ret = m25p_nor_flash_scan(nor->dev);
>
> -       ret = spi_nor_scan(nor, flash_name, mode);
>         if (ret)
>                 return ret;
>
> @@ -248,7 +263,6 @@ static int m25p_probe(struct spi_device *spi)
>                                    data ? data->nr_parts : 0);
>  }
>
> -
>  static int m25p_remove(struct spi_device *spi)
>  {
>         struct m25p     *flash = spi_get_drvdata(spi);
> @@ -319,10 +333,24 @@ static const struct of_device_id m25p_of_table[] = {
>  };
>  MODULE_DEVICE_TABLE(of, m25p_of_table);
>
> +#ifdef CONFIG_PM_SLEEP
> +static int m25p_suspend(struct device *dev)
> +{
> +       return 0;
> +}
> +
> +static int m25p_resume(struct device *dev)
> +{
> +       return m25p_nor_flash_scan(dev);
> +}
> +#endif
> +static SIMPLE_DEV_PM_OPS(m25p_pm_ops, m25p_suspend, m25p_resume);
> +
>  static struct spi_driver m25p80_driver = {
>         .driver = {
>                 .name   = "m25p80",
>                 .of_match_table = m25p_of_table,
> +               .pm     = &m25p_pm_ops,
>         },
>         .id_table       = m25p_ids,
>         .probe  = m25p_probe,
> --
> 1.9.1
>
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