Re: [PATCH 01/11] spi: spi-mem: Extend the SPI mem interface to set a custom memory name

[Frieder Schrempf]

Hi Boris,

On 30.05.2018 16:32, Boris Brezillon wrote:
> Hi Frieder,
>
> On Wed, 30 May 2018 15:14:30 +0200
> Frieder Schrempf <frieder.schrempf@xxxxxxxxx> wrote:
>
> > When porting (Q)SPI controller drivers from the MTD layer to the SPI
> > layer, the naming scheme for the memory devices changes. To be able
> > to keep compatibility with the old drivers naming scheme, a function
> > is added to the SPI mem interface to let controller drivers set a
> > custom name for the memory.
> >
> > Example for the FSL QSPI driver:
> >
> > Name with the old driver: 21e0000.qspi,
> > or with multiple devices: 21e0000.qspi-0, 21e0000.qspi-1, ...
> >
> > Name with the new driver without spi_mem_get_name: spi4.0
> >
> > Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxx>
> > ---
> >   drivers/spi/spi-mem.c       | 25 +++++++++++++++++++++++++
> >   include/linux/spi/spi-mem.h |  3 +++
> >   2 files changed, 28 insertions(+)
> >
> > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> > index 990770d..5e9af47 100644
> > --- a/drivers/spi/spi-mem.c
> > +++ b/drivers/spi/spi-mem.c
> > @@ -311,6 +311,31 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> >   EXPORT_SYMBOL_GPL(spi_mem_exec_op);
> >   
> >   /**
> > + * spi_mem_get_name() - Let drivers using the SPI mem interface specify a
> > + *			custom name for the memory to avoid compatibility
> > + *			issues with ported drivers.
> > + * @mem: the SPI memory
> > + *
> > + * When porting (Q)SPI controller drivers from the MTD layer to the SPI
> > + * layer, the naming scheme for the memory devices changes. To be able to
> > + * keep compatibility with the old drivers naming scheme, this function can
> > + * be used to get a custom name from the controller driver.
> > + * If no custom name is available, the name of the SPI device is returned.
> > + *
> > + * Return: a char array that contains the name for the flash memory
> > + */
> > +const char *spi_mem_get_name(struct spi_mem *mem)
> > +{
> > +	struct spi_controller *ctlr = mem->spi->controller;
> > +
> > +	if (ctlr->mem_ops && ctlr->mem_ops->get_name)
> > +		return ctlr->mem_ops->get_name(mem);
>
> Looks like your implementation of ->get_name() in the fsl driver is
> allocating a new string each time it's called. I guess other
> implementations might be forced to do the same, so maybe it's better to
> add a ->name field to struct spi_mem and only call ->get_name() once
> when the device is probed. Then spi_mem_get_name() can just be
> implemented like this:
>
> const char *spi_mem_get_name(struct spi_mem *mem)
> {
> 	return mem->name;
> }

Sounds like a good proposal. I will change that.

Thanks,

Frieder

> Regards,
>
> Boris
>
> > +
> > +	return dev_name(&mem->spi->dev);
> > +}
> > +EXPORT_SYMBOL_GPL(spi_mem_get_name);
> > +
> > +/**
> >    * spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
> >    *			      match controller limitations
> >    * @mem: the SPI memory
> > diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
> > index 4fa34a2..f1912d3 100644
> > --- a/include/linux/spi/spi-mem.h
> > +++ b/include/linux/spi/spi-mem.h
> > @@ -178,6 +178,7 @@ struct spi_controller_mem_ops {
> >   			    const struct spi_mem_op *op);
> >   	int (*exec_op)(struct spi_mem *mem,
> >   		       const struct spi_mem_op *op);
> > +	const char *(*get_name)(struct spi_mem *mem);
> >   };
> >   
> >   /**
> > @@ -236,6 +237,8 @@ bool spi_mem_supports_op(struct spi_mem *mem,
> >   int spi_mem_exec_op(struct spi_mem *mem,
> >   		    const struct spi_mem_op *op);
> >   
> > +const char *spi_mem_get_name(struct spi_mem *mem);
> > +
> >   int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv,
> >   				       struct module *owner);
> >