RE: [net-next v2 2/9] net: stmmac: platform: Convert to devm_clk_get_enabled() and devm_clk_get_optional_enabled()

[Biju Das]

> -----Original Message-----
> From: Serge Semin <fancer.lancer@xxxxxxxxx>
> Sent: Friday, August 23, 2024 10:37 AM
> To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Cc: Yangtao Li <frank.li@xxxxxxxx>; clement.leger@xxxxxxxxxxx; andrew@xxxxxxx; f.fainelli@xxxxxxxxx;
> olteanv@xxxxxxxxx; davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx;
> ulli.kroll@xxxxxxxxxxxxxx; linus.walleij@xxxxxxxxxx; marcin.s.wojtas@xxxxxxxxx; linux@xxxxxxxxxxxxxxx;
> alexandre.torgue@xxxxxxxxxxx; joabreu@xxxxxxxxxxxx; mcoquelin.stm32@xxxxxxxxx; hkallweit1@xxxxxxxxx;
> kees@xxxxxxxxxx; justinstitt@xxxxxxxxxx; u.kleine-koenig@xxxxxxxxxxxxxx; horms@xxxxxxxxxx;
> sd@xxxxxxxxxxxxxxx; linux-renesas-soc@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-stm32@st-md-
> mailman.stormreply.com; Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
> Subject: Re: [net-next v2 2/9] net: stmmac: platform: Convert to devm_clk_get_enabled() and
> devm_clk_get_optional_enabled()
> 
> Hi Biju
> 
> On Fri, Aug 23, 2024 at 09:15:06AM +0000, Biju Das wrote:
> > Hi Serge Semin,
> >
> > > -----Original Message-----
> > > From: Serge Semin <fancer.lancer@xxxxxxxxx>
> > > Sent: Friday, August 23, 2024 10:11 AM
> > > Subject: Re: [net-next v2 2/9] net: stmmac: platform: Convert to
> > > devm_clk_get_enabled() and
> > > devm_clk_get_optional_enabled()
> > >
> > > Hi Yangtao
> > >
> > > On Fri, Aug 23, 2024 at 01:21:14AM -0600, Yangtao Li wrote:
> > > > Use devm_clk_get_enabled() and devm_clk_get_optional_enabled() to
> > > > simplify code.
> > > >
> > > > Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> > > > Reviewed-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
> > > > ---
> > > > v2:
> > > > -remove unused 'ret'
> > > > -fix incompatible-pointer-types
> > > >
> > > >  .../ethernet/stmicro/stmmac/stmmac_platform.c | 35
> > > > +++++--------------
> > > >  1 file changed, 8 insertions(+), 27 deletions(-)
> > > >
> > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> > > > b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> > > > index ad868e8d195d..1a66baaa4081 100644
> > > > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> > > > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
> > > > @@ -415,8 +415,6 @@ static int stmmac_of_get_mac_mode(struct
> > > > device_node *np)  static void stmmac_remove_config_dt(struct platform_device *pdev,
> > > >  				    struct plat_stmmacenet_data *plat)  {
> > > > -	clk_disable_unprepare(plat->stmmac_clk);
> > > > -	clk_disable_unprepare(plat->pclk);
> > > >  	of_node_put(plat->phy_node);
> > > >  	of_node_put(plat->mdio_node);
> > > >  }
> > > > @@ -436,7 +434,6 @@ stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac)
> > > >  	struct plat_stmmacenet_data *plat;
> > > >  	struct stmmac_dma_cfg *dma_cfg;
> > > >  	int phy_mode;
> > > > -	void *ret;
> > > >  	int rc;
> > > >
> > > >  	plat = devm_kzalloc(&pdev->dev, sizeof(*plat), GFP_KERNEL); @@
> > > > -615,21 +612,16 @@ stmmac_probe_config_dt(struct platform_device
> > > > *pdev, u8 *mac)
> > > >
> > > >  	/* clock setup */
> > > >  	if (!of_device_is_compatible(np, "snps,dwc-qos-ethernet-4.10")) {
> > > > -		plat->stmmac_clk = devm_clk_get(&pdev->dev,
> > > > -						STMMAC_RESOURCE_NAME);
> > > > +		plat->stmmac_clk = devm_clk_get_enabled(&pdev->dev,
> > > > +STMMAC_RESOURCE_NAME);
> > > >  		if (IS_ERR(plat->stmmac_clk)) {
> > > >  			dev_warn(&pdev->dev, "Cannot get CSR clock\n");
> > > >  			plat->stmmac_clk = NULL;
> > > >  		}
> > > > -		clk_prepare_enable(plat->stmmac_clk);
> > > >  	}
> > > >
> > > > -	plat->pclk = devm_clk_get_optional(&pdev->dev, "pclk");
> > > > -	if (IS_ERR(plat->pclk)) {
> > > > -		ret = plat->pclk;
> > > > -		goto error_pclk_get;
> > > > -	}
> > > > -	clk_prepare_enable(plat->pclk);
> > > > +	plat->pclk = devm_clk_get_optional_enabled(&pdev->dev, "pclk");
> > > > +	if (IS_ERR(plat->pclk))
> > >
> > > > +		return (void *)plat->pclk;
> > >
> > > Use the ERR_CAST() macro instead of the open coded void type cast.
> >
> 
> > Which is better ERR_PTR or ERR_CAST in this case?
> 
> The only correct macro in this case is ERR_CAST() which implies one error-pointer cast to another.
> Open-coding the pointers cast is discouraged.
> 
> The ERR_PTR() macro is utilized to cast an _integer-error_ to an error-pointer.

Thanks for the clarification. Make sense.

Cheers,
Biju