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Re: [PATCH v2 1/5] mtd: spi-nor: notify (Q)SPI controller about protocol change

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  Re: [PATCH v2 1/5] mtd: spi-nor: notify (Q)SPI controller about protocol  change Cyrille Pitchen <cyrille.pitchen@atmel.com> - 2015-07-22 18:30 +0200
    Re: [PATCH v2 1/5] mtd: spi-nor: notify (Q)SPI controller about protocol change Marek Vasut <marex@denx.de> - 2015-07-23 09:10 +0200

#1190095 — Re: [PATCH v2 1/5] mtd: spi-nor: notify (Q)SPI controller about protocol change

Hi Marek,

Le 22/07/2015 15:41, Marek Vasut a écrit :
> On Wednesday, July 22, 2015 at 03:17:06 PM, Cyrille Pitchen wrote:
>> Once the Quad SPI mode has been enabled on a Micron flash memory, this
>> device expects ALL the following commands to use the SPI 4-4-4 protocol.
>> The (Q)SPI controller needs to be notified about the protocol change so it
>> can adapt and keep on dialoging with the Micron memory.
>>
>> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
>> ---
>>  drivers/mtd/spi-nor/spi-nor.c | 17 +++++++++++++++++
>>  include/linux/mtd/spi-nor.h   | 13 +++++++++++++
>>  2 files changed, 30 insertions(+)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
>> index d78831b4422b..93627d4e6be8 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -163,6 +163,18 @@ static inline int write_disable(struct spi_nor *nor)
>>  	return nor->write_reg(nor, SPINOR_OP_WRDI, NULL, 0, 0);
>>  }
>>
>> +/*
>> + * Notify the (Q)SPI controller about the new protocol to be used.
> 
> Hi!
> 
> Can you please just reword this a little, so that it is absolutelly clear
> even to the less bright of us (like me) that this is a notification coming
> from the upper layers (ie. the spi-nor framework) toward the hardware ?
> 
Sure, no problem! what about the following?

/*
 * Let the spi-nor framework notify lower layers, especially the driver of the
 * (Q)SPI controller, about the new protocol to be used. Indeed, once the
 * spi-nor framework has sent manufacturer specific commands to a memory to
 * enable its Quad SPI mode, it should immediately after tell the QSPI
 * controller to use the very same Quad SPI protocol as expected by the memory.
 */

>> + */
>> +static inline int spi_nor_set_protocol(struct spi_nor *nor,
>> +				       enum spi_protocol proto)
>> +{
>> +	if (nor->set_protocol)
>> +		return nor->set_protocol(nor, proto);
>> +
>> +	return 0;
>> +}
>> +
>>  static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
>>  {
>>  	return mtd->priv;
> 
> [...]
> 
> Best regards,
> Marek Vasut
> 
Best regards,

Cyrille
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#1190671 — Re: [PATCH v2 1/5] mtd: spi-nor: notify (Q)SPI controller about protocol change

On Wednesday, July 22, 2015 at 06:25:20 PM, Cyrille Pitchen wrote:
> Hi Marek,
> 
> Le 22/07/2015 15:41, Marek Vasut a écrit :
> > On Wednesday, July 22, 2015 at 03:17:06 PM, Cyrille Pitchen wrote:
> >> Once the Quad SPI mode has been enabled on a Micron flash memory, this
> >> device expects ALL the following commands to use the SPI 4-4-4 protocol.
> >> The (Q)SPI controller needs to be notified about the protocol change so
> >> it can adapt and keep on dialoging with the Micron memory.
> >> 
> >> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
> >> ---
> >> 
> >>  drivers/mtd/spi-nor/spi-nor.c | 17 +++++++++++++++++
> >>  include/linux/mtd/spi-nor.h   | 13 +++++++++++++
> >>  2 files changed, 30 insertions(+)
> >> 
> >> diff --git a/drivers/mtd/spi-nor/spi-nor.c
> >> b/drivers/mtd/spi-nor/spi-nor.c index d78831b4422b..93627d4e6be8 100644
> >> --- a/drivers/mtd/spi-nor/spi-nor.c
> >> +++ b/drivers/mtd/spi-nor/spi-nor.c
> >> @@ -163,6 +163,18 @@ static inline int write_disable(struct spi_nor
> >> *nor)
> >> 
> >>  	return nor->write_reg(nor, SPINOR_OP_WRDI, NULL, 0, 0);
> >>  
> >>  }
> >> 
> >> +/*
> >> + * Notify the (Q)SPI controller about the new protocol to be used.
> > 
> > Hi!
> > 
> > Can you please just reword this a little, so that it is absolutelly clear
> > even to the less bright of us (like me) that this is a notification
> > coming from the upper layers (ie. the spi-nor framework) toward the
> > hardware ?
> 
> Sure, no problem! what about the following?
> 
> /*
>  * Let the spi-nor framework notify lower layers, especially the driver of
> the * (Q)SPI controller, about the new protocol to be used. Indeed, once
> the * spi-nor framework has sent manufacturer specific commands to a
> memory to * enable its Quad SPI mode, it should immediately after tell the
> QSPI * controller to use the very same Quad SPI protocol as expected by
> the memory. */

Sure, excellent, thanks ! :-)
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