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

Biju Das
2024-08-23T09:41:54Z

> -----Original Message-----
> From: Serge Semin <fancer.lancer@gmail.com>
> Sent: Friday, August 23, 2024 10:37 AM
> To: Biju Das <biju.das.jz@bp.renesas.com>
> Cc: Yangtao Li <frank.li@vivo.com>; clement.leger@bootlin.com; andrew@lunn.ch; f.fainelli@gmail.com;
> olteanv@gmail.com; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com;
> ulli.kroll@googlemail.com; linus.walleij@linaro.org; marcin.s.wojtas@gmail.com; linux@armlinux.org.uk;
> alexandre.torgue@foss.st.com; joabreu@synopsys.com; mcoquelin.stm32@gmail.com; hkallweit1@gmail.com;
> kees@kernel.org; justinstitt@google.com; u.kleine-koenig@pengutronix.de; horms@kernel.org;
> sd@queasysnail.net; linux-renesas-soc@vger.kernel.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-stm32@st-md-
> mailman.stormreply.com; Maxime Chevallier <maxime.chevallier@bootlin.com>
> 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@gmail.com>
> > > 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@vivo.com>
> > > > Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> > > > ---
> > > > 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