linux-kernel - Re: [PATCH 1/2] pinctrl: qcom: msm8226: Add MPM pin mappings

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Message-ID: <7570584.EvYhyI6sBW@z3ntu.xyz>
Date:   Sat, 23 Sep 2023 13:19:46 +0200
From:   Luca Weiss <luca@...tu.xyz>
To:     Stephan Gerhold <stephan@...hold.net>
Cc:     linux-arm-msm@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org,
        Matti Lehtimäki <matti.lehtimaki@...il.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] pinctrl: qcom: msm8226: Add MPM pin mappings

On Samstag, 23. September 2023 12:00:52 CEST Stephan Gerhold wrote:
> On Sat, Sep 23, 2023 at 11:32:47AM +0200, Luca Weiss wrote:
> > Hi Matti,
> > 
> > On Samstag, 23. September 2023 00:40:26 CEST Matti Lehtimäki wrote:
> > > Add pin <-> wakeirq mappings to allow for waking up the AP from sleep
> > > through MPM-connected pins.
> > > 
> > > Signed-off-by: Matti Lehtimäki <matti.lehtimaki@...il.com>
> > > ---
> > > 
> > >  drivers/pinctrl/qcom/pinctrl-msm8226.c | 12 ++++++++++++
> > >  1 file changed, 12 insertions(+)
> > > 
> > > diff --git a/drivers/pinctrl/qcom/pinctrl-msm8226.c
> > > b/drivers/pinctrl/qcom/pinctrl-msm8226.c index
> > > 994619840a70..1e46a9ab382f
> > > 100644
> > > --- a/drivers/pinctrl/qcom/pinctrl-msm8226.c
> > > +++ b/drivers/pinctrl/qcom/pinctrl-msm8226.c
> > > @@ -612,6 +612,16 @@ static const struct msm_pingroup msm8226_groups[] =
> > > {
> > > 
> > >  #define NUM_GPIO_PINGROUPS 117
> > > 
> > > +static const struct msm_gpio_wakeirq_map msm8226_mpm_map[] = {
> > > +	{ 1, 3 }, { 4, 4 }, { 5, 5 }, { 9, 6 }, { 13, 7 }, { 17, 8 },
> > 
> > I'm not really convinced this is the correct order of values...
> > 
> > Let's look at downstream:
> >   qcom,gpio-map = <3  1>,
> >   
> >                   <4  4 >,
> >                   <5  5 >,
> >                   <6  9 >,
> >                   [...]
> > 
> > From Documentation/devicetree/bindings/arm/msm/mpm.txt downstream:
> >   Each tuple represents a MPM pin and which GIC interrupt is routed to it.
> > 
> > So first is pin number, second is interrupt number.
> > 
> > And check mainline:
> >   /**
> >   
> >    * struct msm_gpio_wakeirq_map - Map of GPIOs and their wakeup pins
> >    * @gpio:          The GPIOs that are wakeup capable
> >    * @wakeirq:       The interrupt at the always-on interrupt controller
> >    */
> >   
> >   struct msm_gpio_wakeirq_map {
> >   
> >   	unsigned int gpio;
> >   	unsigned int wakeirq;
> >   
> >   };
> > 
> > So here we also have the order pin-interrupt, not the reverse order.
> > 
> > Therefore I believe the order in this patch is incorrect, and it should
> > rather> 
> > be:
> >   { 3, 1 }, { 4, 4 }, { 5, 5 }, { 6, 9 }, { 7, 13 }, { 8, 17 },
> >   [...]
> > 
> > Or do you think I'm missing something?
> 
> Yes :)
> 
> Let's look at the later entries:
> > > +	{ 21, 9 }, { 27, 10 }, { 29, 11 }, { 31, 12 }, { 33, 13 }, { 35, 14
> > 
> > },
> > 
> > > +	{ 37, 15 }, { 38, 16 }, { 39, 17 }, { 41, 18 }, { 46, 19 }, { 48, 20
> > 
> > },
> > 
> > > +	{ 49, 21 }, { 50, 22 }, { 51, 23 }, { 52, 24 }, { 54, 25 }, { 62, 26
> > 
> > },
> > 
> > > +	{ 63, 27 }, { 64, 28 }, { 65, 29 }, { 66, 30 }, { 67, 31 }, { 68, 32
> > 
> > },
> > 
> > > +	{ 69, 33 }, { 71, 34 }, { 72, 35 }, { 106, 36 }, { 107, 37 },
> > > +	{ 108, 38 }, { 109, 39 }, { 110, 40 }, { 111, 54 }, { 113, 55 },
> > > +};
> > > +
> 
> For example: { 113, 55 }, i.e. { .gpio = 113, .wakeirq = 55 }.
> 
> MSM8226 has GPIOs 0-116 and 64 MPM pins/interrupts. The order in this
> patch is the only one that can be correct because the definition would
> be invalid the other way around. 113 must be the GPIO number because it
> is larger than the 64 available MPM interrupt pins. :)

So basically you're saying downstream is wrong / buggy?

From qcom,gpio-map = [...], <55 113>; it's taking the properties like this
(drivers/soc/qcom/mpm-of.c):

  unsigned long pin = be32_to_cpup(list++);
  irq_hw_number_t hwirq = be32_to_cpup(list++);

Your explanation does make sense I guess but somewhere the link downstream -> 
mainline must be broken, no?

Regards
Luca


> 
> Thanks,
> Stephan