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List:       linux-clk
Subject:    Re: [PATCH v6 08/17] reset: npcm: using syscon instead of device data
From:       Philipp Zabel <p.zabel () pengutronix ! de>
Date:       2022-06-30 14:53:01
Message-ID: c01103ae5582cda01708c25ddc3f9bb538c67ab0.camel () pengutronix ! de
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On Do, 2022-06-30 at 14:20 +0300, Tomer Maimon wrote:
> Hi Philipp,
> 
> Thanks for your comment.
> 
> On Thu, 30 Jun 2022 at 13:59, Philipp Zabel <p.zabel@pengutronix.de> wrote:
> > 
> > Hi Tomer,
> > 
> > On Do, 2022-06-30 at 13:35 +0300, Tomer Maimon wrote:
> > Using syscon device tree property instead of device data to handle the
> > NPCM general control registers.
> > 
> > In case the syscon not found the code still search for nuvoton,npcm750-gcr
> > to support DTS backward compatibility.
> > 
> > Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> > ---
> > drivers/reset/reset-npcm.c | 17 ++++++++---------
> > 1 file changed, 8 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/reset/reset-npcm.c b/drivers/reset/reset-npcm.c
> > index 2ea4d3136e15..431ff2b602c5 100644
> > --- a/drivers/reset/reset-npcm.c
> > +++ b/drivers/reset/reset-npcm.c
> > @@ -138,8 +138,7 @@ static int npcm_reset_xlate(struct reset_controller_dev \
> > *rcdev, }
> > 
> > 
> > static const struct of_device_id npcm_rc_match[] = {
> > -       { .compatible = "nuvoton,npcm750-reset",
> > -               .data = (void *)"nuvoton,npcm750-gcr" },
> > +       { .compatible = "nuvoton,npcm750-reset"},
> > 
> > Add a space.                                  ^^
> Will modify in V7
> > 
> > { }
> > };
> > 
> > 
> > @@ -155,15 +154,15 @@ static int npcm_usb_reset(struct platform_device *pdev, \
> > struct npcm_rc_data *rc) u32 ipsrst1_bits = 0;
> > u32 ipsrst2_bits = NPCM_IPSRST2_USB_HOST;
> > u32 ipsrst3_bits = 0;
> > -       const char *gcr_dt;
> > 
> > 
> > -       gcr_dt = (const char *)
> > -       of_match_device(dev->driver->of_match_table, dev)->data;
> > -
> > -       gcr_regmap = syscon_regmap_lookup_by_compatible(gcr_dt);
> > +       gcr_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, \
> > "nuvoton,sysgcr"); if (IS_ERR(gcr_regmap)) {
> > -               dev_err(&pdev->dev, "Failed to find %s\n", gcr_dt);
> > -               return PTR_ERR(gcr_regmap);
> > +               dev_warn(&pdev->dev, "Failed to find nuvoton,sysgcr search for \
> > nuvoton,npcm750-gcr for Poleg backward compatibility"); 
> > Is this warning useful to the user? Maybe add suggestion like "please
> > update the device tree". Also there is no further message if
> > nuvoton,npcm750-gcr is found and all is well.
> 
> O.K.
> I think about two options:
> 
> 1. Modify the message "Failed to find nuvoton,sysgcr property, please
> update the device tree\n Search for nuvoton,npcm750-gcr for Poleg
> backward compatibility"

I would replace "Search for" with "Using"
The second line probably should be dev_info() level.

> OR
> 
> 2.
> if (IS_ERR(rc->gcr_regmap)) {
> dev_warn(&pdev->dev, "Failed to find nuvoton,sysgcr
> please update the device tree");
> rc->gcr_regmap =
> syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr");
> if (IS_ERR(rc->gcr_regmap)) {
> dev_err(&pdev->dev, "Failed to find
> nuvoton,npcm750-gcr");
> return PTR_ERR(rc->gcr_regmap);
> }
> dev_info(&pdev->dev, "found nuvoton,npcm750-gcr for
> Poleg backward compatibility");
> }
> 
> The only problem that I have with option 2 is if our customers will
> use the latest reset driver and they will not update their device tree
> they will see all the time the dev_info message.
> 
> What do you think?

I'm fine with either. With the "please update DT" prompt it's clear how
to get rid of the warning.

regards
Philipp


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