Re: [PATCH v10 4/5] wifi: brcmfmac: Add optional lpo clock enable support

[Alexey Charkov <alchark@gmail.com>]

Hi Arend, Jacobe,

On Tuesday, August 13, 2024 2:57:28 PM GMT+3 Arend van Spriel wrote:
> On 8/13/2024 10:20 AM, Jacobe Zang wrote:
> > WiFi modules often require 32kHz clock to function. Add support to
> > enable the clock to PCIe driver and move "brcm,bcm4329-fmac" check
> > to the top of brcmf_of_probe. Change function prototypes from void
> > to int and add appropriate errno's for return values that will be
> > send to bus when error occurred.
> 
> I was going to say it looks good to me, but....
> 
> > Co-developed-by: Ondrej Jirman <megi@xff.cz>
> > Signed-off-by: Ondrej Jirman <megi@xff.cz>
> > Co-developed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> > Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> > Reviewed-by: Sai Krishna <saikrishnag@marvell.com>
> > Signed-off-by: Jacobe Zang <jacobe.zang@wesion.com>
> > ---
> > 
> >   .../broadcom/brcm80211/brcmfmac/bcmsdh.c      |  4 +-
> >   .../broadcom/brcm80211/brcmfmac/common.c      |  3 +-
> >   .../wireless/broadcom/brcm80211/brcmfmac/of.c | 53 +++++++++++--------
> >   .../wireless/broadcom/brcm80211/brcmfmac/of.h |  9 ++--
> >   .../broadcom/brcm80211/brcmfmac/pcie.c        |  3 ++
> >   .../broadcom/brcm80211/brcmfmac/sdio.c        | 22 +++++---
> >   .../broadcom/brcm80211/brcmfmac/usb.c         |  3 ++
> >   7 files changed, 61 insertions(+), 36 deletions(-)
> 
> [...]
> 
> > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> > b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c index
> > e406e11481a62..f19dc7355e0e8 100644
> > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> 
> [...]
> 
> > @@ -113,33 +118,39 @@ void brcmf_of_probe(struct device *dev, enum
> > brcmf_bus_type bus_type,> 
> >   		of_node_put(root);
> >   	
> >   	}
> > 
> > -	if (!np || !of_device_is_compatible(np, "brcm,bcm4329-fmac"))
> > -		return;
> > -
> > 
> >   	err = brcmf_of_get_country_codes(dev, settings);
> >   	if (err)
> >   	
> >   		brcmf_err("failed to get OF country code map (err=%d)
\n", err);
> >   	
> >   	of_get_mac_address(np, settings->mac);
> > 
> > -	if (bus_type != BRCMF_BUSTYPE_SDIO)
> > -		return;
> > +	if (bus_type == BRCMF_BUSTYPE_SDIO) {
> 
> Don't like the fact that this now has an extra indentation level and it
> offers no extra benefit. Just keep the original if-statement and return
> 0. Consequently the LPO clock code should move just before the if-statement.
> > +		if (of_property_read_u32(np, "brcm,drive-strength", 
&val) == 0)
> > +			sdio->drive_strength = val;
> > 
> > -	if (of_property_read_u32(np, "brcm,drive-strength", &val) == 0)
> > -		sdio->drive_strength = val;
> > +		/* make sure there are interrupts defined in the node */
> > +		if (!of_property_present(np, "interrupts"))
> > +			return 0;
> > 
> > -	/* make sure there are interrupts defined in the node */
> > -	if (!of_property_present(np, "interrupts"))
> > -		return;
> > +		irq = irq_of_parse_and_map(np, 0);
> > +		if (!irq) {
> > +			brcmf_err("interrupt could not be 
mapped\n");
> > +			return 0;
> > +		}
> > +		irqf = irqd_get_trigger_type(irq_get_irq_data(irq));
> > +
> > +		sdio->oob_irq_supported = true;
> > +		sdio->oob_irq_nr = irq;
> > +		sdio->oob_irq_flags = irqf;
> > +	}
> > 
> > -	irq = irq_of_parse_and_map(np, 0);
> > -	if (!irq) {
> > -		brcmf_err("interrupt could not be mapped\n");
> > -		return;
> > +	clk = devm_clk_get_optional_enabled(dev, "lpo");
> > +	if (!IS_ERR_OR_NULL(clk)) {
> > +		brcmf_dbg(INFO, "enabling 32kHz clock\n");
> > +		return clk_set_rate(clk, 32768);
> > +	} else {
> > +		return PTR_ERR_OR_ZERO(clk);
> > 
> >   	}
> 
> Change this to:
>  > +	clk = devm_clk_get_optional_enabled(dev, "lpo");
>  > +	if (IS_ERR_OR_NULL(clk)) {
>  > +		return PTR_ERR_OR_ZERO(clk);

Perhaps in this case we should go for IS_ERR and PTR_ERR respectively. 
devm_clk_get_optional_enabled would return NULL when the optional clock is not 
found, so NULL is not an error state but serves as a dummy clock that can be 
used with clk_set_rate.

This way we won't skip over the interrupts initialization below in case the 
clock is absent.

>  > +	}
>  > +	brcmf_dbg(INFO, "enabling 32kHz clock\n");
>  > +	clk_set_rate(clk, 32768);
> 
> As said above this should be moved before the if-statement:
>  > -	if (bus_type != BRCMF_BUSTYPE_SDIO)
>  > -		return 0;
> > 
> > -	irqf = irqd_get_trigger_type(irq_get_irq_data(irq));
> > 
> > -	sdio->oob_irq_supported = true;
> > -	sdio->oob_irq_nr = irq;
> > -	sdio->oob_irq_flags = irqf;
> > +	return 0;
> > 
> >   }

Best regards,
Alexey