linux-kernel - RE: [PATCH 3/6] nvmem: core: add nvmem cell post processing callback

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Message-ID: <DB8PR04MB679522814EBB72EE06B37A0AE6A39@DB8PR04MB6795.eurprd04.prod.outlook.com>
Date:   Thu, 23 Sep 2021 02:52:08 +0000
From:   Joakim Zhang <qiangqing.zhang@....com>
To:     Ahmad Fatoum <a.fatoum@...gutronix.de>,
        "srinivas.kandagatla@...aro.org" <srinivas.kandagatla@...aro.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>
CC:     "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 3/6] nvmem: core: add nvmem cell post processing callback


Hi Ahmad,

> -----Original Message-----
> From: Ahmad Fatoum <a.fatoum@...gutronix.de>
> Sent: 2021年9月22日 19:37
> To: Joakim Zhang <qiangqing.zhang@....com>;
> srinivas.kandagatla@...aro.org; robh+dt@...nel.org; shawnguo@...nel.org
> Cc: devicetree@...r.kernel.org; dl-linux-imx <linux-imx@....com>;
> kernel@...gutronix.de; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 3/6] nvmem: core: add nvmem cell post processing
> callback
> 
> On 08.09.21 12:02, Joakim Zhang wrote:
> > From: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> >
> > Some NVMEM providers have certain nvmem cells encoded, which requires
> > post processing before actually using it.
> >
> > For example mac-address is stored in either in ascii or delimited or
> reverse-order.
> >
> > Having a post-process callback hook to provider drivers would enable
> > them to do this vendor specific post processing before nvmem consumers see
> it.
> >
> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@....com>
> > ---
> >  drivers/nvmem/core.c           | 9 +++++++++
> >  include/linux/nvmem-provider.h | 5 +++++
> >  2 files changed, 14 insertions(+)
> >
> > diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index
> > 23c08dbaf45e..4f81a3adf081 100644
> > --- a/drivers/nvmem/core.c
> > +++ b/drivers/nvmem/core.c
> > @@ -38,6 +38,7 @@ struct nvmem_device {
> >  	unsigned int		nkeepout;
> >  	nvmem_reg_read_t	reg_read;
> >  	nvmem_reg_write_t	reg_write;
> > +	nvmem_cell_post_process_t cell_post_process;
> >  	struct gpio_desc	*wp_gpio;
> >  	void *priv;
> >  };
> > @@ -797,6 +798,7 @@ struct nvmem_device *nvmem_register(const struct
> nvmem_config *config)
> >  	nvmem->type = config->type;
> >  	nvmem->reg_read = config->reg_read;
> >  	nvmem->reg_write = config->reg_write;
> > +	nvmem->cell_post_process = config->cell_post_process;
> >  	nvmem->keepout = config->keepout;
> >  	nvmem->nkeepout = config->nkeepout;
> >  	if (config->of_node)
> > @@ -1404,6 +1406,13 @@ static int __nvmem_cell_read(struct
> nvmem_device *nvmem,
> >  	if (cell->bit_offset || cell->nbits)
> >  		nvmem_shift_read_buffer_in_place(cell, buf);
> >
> > +	if (nvmem->cell_post_process) {
> > +		rc = nvmem->cell_post_process(nvmem->priv, cell->type,
> > +					      cell->offset, buf, cell->bytes);
> > +		if (rc)
> > +			return rc;
> > +	}
> > +
> >  	if (len)
> >  		*len = cell->bytes;
> >
> > diff --git a/include/linux/nvmem-provider.h
> > b/include/linux/nvmem-provider.h index 104505e9028f..d980c79f9605
> > 100644
> > --- a/include/linux/nvmem-provider.h
> > +++ b/include/linux/nvmem-provider.h
> > @@ -19,6 +19,9 @@ typedef int (*nvmem_reg_read_t)(void *priv, unsigned
> int offset,
> >  				void *val, size_t bytes);
> >  typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
> >  				 void *val, size_t bytes);
> > +/* used for vendor specific post processing of cell data */ typedef
> > +int (*nvmem_cell_post_process_t)(void *priv, int type, unsigned int offset,
> > +					  void *buf, size_t bytes);
> >
> >  enum nvmem_type {
> >  	NVMEM_TYPE_UNKNOWN = 0,
> > @@ -62,6 +65,7 @@ struct nvmem_keepout {
> >   * @no_of_node:	Device should not use the parent's of_node even if
> it's !NULL.
> >   * @reg_read:	Callback to read data.
> >   * @reg_write:	Callback to write data.
> > + * @cell_read_callback: Callback for vendor specific post processing
> > + of cell data
> 
> The member below is called cell_post_process

Good caught! Will fix it in V2. Thanks.

Best Regards,
Joakim Zhang
> >   * @size:	Device size.
> >   * @word_size:	Minimum read/write access granularity.
> >   * @stride:	Minimum read/write access stride.
> > @@ -92,6 +96,7 @@ struct nvmem_config {
> >  	bool			no_of_node;
> >  	nvmem_reg_read_t	reg_read;
> >  	nvmem_reg_write_t	reg_write;
> > +	nvmem_cell_post_process_t cell_post_process;
> >  	int	size;
> >  	int	word_size;
> >  	int	stride;
> >
> 
> 
> --
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