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Message-ID: <8de856d4-8526-4662-bb29-898b80476df9@broadcom.com>
Date: Wed, 14 Aug 2024 12:44:58 +0200
From: Arend van Spriel <arend.vanspriel@...adcom.com>
To: Alexey Charkov <alchark@...il.com>, Jacobe Zang <jacobe.zang@...ion.com>
Cc: 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, linux-rockchip@...ts.infradead.org,
efectn@...tonmail.com, dsimic@...jaro.org, jagan@...eble.ai,
devicetree@...r.kernel.org, linux-arm-kernel@...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 8/14/2024 11:48 AM, Alexey Charkov wrote:
> On Wed, Aug 14, 2024 at 12:27 PM Jacobe Zang <jacobe.zang@...ion.com> wrote:
>>
>>
>>
>> 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@....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);
>>>
>>> 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);
>> + }
>
> If clk is NULL then clk_set_rate returns immediately with status zero,
> so there is little difference from whether you wrap it into another if
> (clk) or not. You can probably drop the debug statement altogether and
> call clk_set_rate unconditionally - this will look neater.
The construct above is indeed only needed to get the debug statement
correct given the behavior of clk_set_rate(). However, for debugging it
is useful to know that the LPO clock is defined and used or not. Maybe
do this:
clk = devm_clk_get_optional_enabled(dev, "lpo");
if (IS_ERR(clk))
return PTR_ERR(clk);
brcmf_dbg(INFO, "%s LPO clock\n", clk ? "enable" : "no");
clk_set_rate(clk, 32768);
Regards,
Arend
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