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

[Jacobe Zang <jacobe.zang@wesion.com>]

On 2024/8/14 16:47, Alexey Charkov wrote:
> 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.

I think we don't need to set clock rate for clock is NULL. So it should 
be changed to:

+	clk = devm_clk_get_optional_enabled(dev, "lpo");
+	if (IS_ERR(clk)) {
+		return PTR_ERR(clk);
+	} else if (clk) {
+		brcmf_dbg(INFO, "enabling 32kHz clock\n");
+		clk_set_rate(clk, 32768);
+	}

> 
> 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
Jacobe