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

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

[Kamal Dasu]

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 intial probe and needed on resume().
The spi-nor stucture 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@gmail.com>
---
 drivers/mtd/devices/m25p80.c | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 9cf7fcd..f8294b4 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -248,7 +248,6 @@ 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 +318,46 @@ 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)
+{
+	struct m25p *flash = dev_get_drvdata(dev);
+	struct flash_platform_data	*data;
+	char *flash_name = NULL;
+	enum read_mode mode = SPI_NOR_NORMAL;
+	int ret;
+
+	data = dev_get_platdata(&flash->spi->dev);
+
+	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;
+
+	ret = spi_nor_scan(&flash->spi_nor, flash_name, mode);
+
+	return ret;
+}
+#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

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

[Geert Uytterhoeven]

On Fri, Sep 9, 2016 at 9:13 PM, Kamal Dasu <kdasu.kdev@gmail.com> 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 intial probe and needed on resume().
> The spi-nor stucture 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@gmail.com>
> ---
>  drivers/mtd/devices/m25p80.c | 37 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 9cf7fcd..f8294b4 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c

> +static int m25p_resume(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;
> +       int ret;
> +
> +       data = dev_get_platdata(&flash->spi->dev);
> +
> +       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;
> +
> +       ret = spi_nor_scan(&flash->spi_nor, flash_name, mode);

All of the above is also done in m25p_probe(). Hence please factor out the
commonalities into its own function.

> +
> +       return ret;
> +}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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

[Kamal Dasu]

Geert,

 I agree that scan code can be refactored into a common function to be
called by probe and resume. Will send a v2 patch with the changes.

Thanks
Kamal

On Sun, Sep 11, 2016 at 6:10 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> On Fri, Sep 9, 2016 at 9:13 PM, Kamal Dasu <kdasu.kdev@gmail.com> 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 intial probe and needed on resume().
>> The spi-nor stucture 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@gmail.com>
>> ---
>>  drivers/mtd/devices/m25p80.c | 37 ++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 36 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
>> index 9cf7fcd..f8294b4 100644
>> --- a/drivers/mtd/devices/m25p80.c
>> +++ b/drivers/mtd/devices/m25p80.c
>
>> +static int m25p_resume(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;
>> +       int ret;
>> +
>> +       data = dev_get_platdata(&flash->spi->dev);
>> +
>> +       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;
>> +
>> +       ret = spi_nor_scan(&flash->spi_nor, flash_name, mode);
>
> All of the above is also done in m25p_probe(). Hence please factor out the
> commonalities into its own function.
>
>> +
>> +       return ret;
>> +}
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds