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

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Message-ID: <de80a665-07d2-4b38-9415-5ee1ed09e690@broadcom.com>
Date: Tue, 13 Aug 2024 20:31:52 +0200
From: Arend van Spriel <arend.vanspriel@...adcom.com>
To: Jacobe Zang <jacobe.zang@...ion.com>, robh@...nel.org,
 krzk+dt@...nel.org, heiko@...ech.de, kvalo@...nel.org, davem@...emloft.net,
 edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com, conor+dt@...nel.org
Cc: efectn@...tonmail.com, dsimic@...jaro.org, jagan@...eble.ai,
 devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org,
 arend@...adcom.com, linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
 megi@....cz, duoming@....edu.cn, bhelgaas@...gle.com,
 minipli@...ecurity.net, brcm80211@...ts.linux.dev,
 brcm80211-dev-list.pdl@...adcom.com, nick@...das.com,
 Sai Krishna <saikrishnag@...vell.com>
Subject: Re: [PATCH v10 4/5] wifi: brcmfmac: Add optional lpo clock enable
 support

On 8/13/2024 1:57 PM, 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@....cz>
>> Signed-off-by: Ondrej Jirman <megi@....cz>
>> Co-developed-by: Arend van Spriel <arend.vanspriel@...adcom.com>
>> Signed-off-by: Arend van Spriel <arend.vanspriel@...adcom.com>
>> Reviewed-by: Sai Krishna <saikrishnag@...vell.com>
>> Signed-off-by: Jacobe Zang <jacobe.zang@...ion.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);
>  > +    }
>  > +    brcmf_dbg(INFO, "enabling 32kHz clock\n");
>  > +    clk_set_rate(clk, 32768);

Do we really need to set the clock rate or could that be defined in the 
devicetree? Just wondering. I have looked at the clock.yaml schema, but 
not really an idea what is needed in the devicetree spec. Any pointers 
from DT devs would be appreciated or a hard no-do-not-do-that is also 
fine ;-)

Regards,
Arend