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Date: Thu, 28 Oct 2021 09:58:44 +0100
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
Linus Walleij <linus.walleij@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Geert Uytterhoeven <geert+renesas@...der.be>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
Biju Das <biju.das.jz@...renesas.com>
Subject: Re: [PATCH 4/4] pinctrl: renesas: pinctrl-rzg2l: Add support to
get/set drive-strength and output-impedance-ohms
Hi Geert,
Thank you for the review.
On Thu, Oct 28, 2021 at 8:56 AM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Wed, Oct 27, 2021 at 3:45 PM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@...renesas.com> wrote:
> > Add support to get/set drive-strength and output-impedance-ohms
> > for the supported pins.
> >
> > While at it also renamed the below macros to match the HW manual,
> > PIN_CFG_IOLH_SD0 -> PIN_CFG_IO_VMC_SD0
> > PIN_CFG_IOLH_SD1 -> PIN_CFG_IO_VMC_SD1
> > PIN_CFG_IOLH_QSPI -> PIN_CFG_IO_VMC_QSPI
> > PIN_CFG_IOLH_ETH0 -> PIN_CFG_IO_VMC_ETH0
> > PIN_CFG_IOLH_ETH1 -> PIN_CFG_IO_VMC_ETH1
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > Reviewed-by: Biju Das <biju.das.jz@...renesas.com>
>
> Thanks for the update!
>
> > ---
> > RFC->v1
> > * Renamed macros to match HW manual
>
> You may want to split that off into a separate patch, as not all lines
> changed are touched for other reasons.
Sure will do.
> BTW, where do I find these "VMC" names in the HW manual?
>
I have shortened VOLTAGE MODE CONTROL to VMC from ETH_ch0/1, SD_ch0/1
and QSPI registers.
> > * Added PIN_CFG_IOLH_A/B macros to differentiate Group A/B
> > * Added helper function to read/rmw pin config
> > * Included RB tags
>
> > --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> > +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
>
> > +static u32 rzg2l_read_pin_config(void __iomem *addr,
> > + u8 bit, u32 mask)
>
> The above fits on a single line.
>
> > +{
> > + void __iomem *addr_adjust = addr;
> > + u8 bit_adjust = bit;
>
> No need for these, just operate on addr and bit directly.
>
will do.
> > + u32 reg;
> > +
> > + if (bit >= 4) {
> > + bit_adjust -= 4;
> > + addr_adjust += 4;
> > + }
> > +
> > + reg = readl(addr_adjust) & (mask << (bit_adjust * 8));
> > + return (reg >> (bit_adjust * 8));
> > +}
> > +
> > +static void rzg2l_rmw_pin_config(void __iomem *addr,
> > + u8 bit, u32 mask, u32 val)
> > +{
>
> The above fits on a single line.
>
will adjust that.
> > + void __iomem *addr_adjust = addr;
> > + u8 bit_adjust = bit;
>
> No need for these, just operate on addr and bit directly.
>
OK.
> > + u32 reg;
> > +
> > + if (bit >= 4) {
> > + bit_adjust -= 4;
> > + addr_adjust += 4;
> > + }
> > +
> > + reg = readl(addr_adjust) & ~(mask << (bit_adjust * 8));
> > +
> > + writel(reg | val, addr_adjust);
>
> I think you should handle "val << (bit * 8)" here, instead of in
> all callers.
>
Agreed.
> > +}
>
> Please split the introduction of these helpers (and add conversion
> of the existing PIN_CONFIG_INPUT_ENABLE handling) off into a separate
> patch.
>
Agreed, will do.
> > @@ -484,6 +544,34 @@ static int rzg2l_pinctrl_pinconf_get(struct pinctrl_dev *pctldev,
> > break;
> > }
> >
> > + case PIN_CONFIG_DRIVE_STRENGTH: {
> > + static const unsigned int mA[4] = { 2, 4, 8, 12 };
> > +
> > + if (!(cfg & PIN_CFG_IOLH_A))
> > + return -EINVAL;
> > +
> > + spin_lock_irqsave(&pctrl->lock, flags);
> > + addr = pctrl->base + IOLH(port);
> > + reg = rzg2l_read_pin_config(addr, bit, IOLH_MASK);
> > + arg = mA[reg];
> > + spin_unlock_irqrestore(&pctrl->lock, flags);
>
> Do you need the spinlock for reading?
>
Yes, to avoid any mishaps, I also looked at pinctrl.c which uses
spinlock while reading.
> > + break;
> > + }
> > +
> > + case PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS: {
> > + static const unsigned int oi[4] = { 100, 66, 50, 33 };
> > +
> > + if (!(cfg & PIN_CFG_IOLH_B))
> > + return -EINVAL;
> > +
> > + spin_lock_irqsave(&pctrl->lock, flags);
> > + addr = pctrl->base + IOLH(port);
> > + reg = rzg2l_read_pin_config(addr, bit, IOLH_MASK);
> > + arg = oi[reg];
> > + spin_unlock_irqrestore(&pctrl->lock, flags);
>
> Likewise.
>
> > + break;
> > + }
> > +
> > default:
> > return -ENOTSUPP;
> > }
>
> > @@ -564,6 +659,49 @@ static int rzg2l_pinctrl_pinconf_set(struct pinctrl_dev *pctldev,
> > spin_unlock_irqrestore(&pctrl->lock, flags);
> > break;
> > }
> > +
> > + case PIN_CONFIG_DRIVE_STRENGTH: {
> > + unsigned int arg = pinconf_to_config_argument(_configs[i]);
> > + static const unsigned int mA[4] = { 2, 4, 8, 12 };
>
> Duplicate, move to file scope?
>
Ok will do.
> > +
> > + if (!(cfg & PIN_CFG_IOLH_A))
> > + return -EINVAL;
> > +
> > + for (i = 0; i < ARRAY_SIZE(mA); i++) {
> > + if (arg == mA[i])
> > + break;
> > + }
> > + if (i >= ARRAY_SIZE(mA))
> > + return -EINVAL;
> > +
> > + spin_lock_irqsave(&pctrl->lock, flags);
> > + addr = pctrl->base + IOLH(port);
> > + rzg2l_rmw_pin_config(addr, bit, IOLH_MASK, (i << (bit * 8)));
>
> Pass pctrl and offset instead of addr (also for rzg2l_read_pin_config,
> for symmetry), and move locking into rzg2l_rmw_pin_config()?
> Taking all of the above into account, that would become:
>
Agreed.
> rzg2l_rmw_pin_config(pctrl, IOLH(port), bit, IOLH_MASK, i);
>
That looks much cleaner.
> > + spin_unlock_irqrestore(&pctrl->lock, flags);
> > + break;
> > + }
> > +
> > + case PIN_CONFIG_OUTPUT_IMPEDANCE_OHMS: {
> > + unsigned int arg = pinconf_to_config_argument(_configs[i]);
> > + static const unsigned int oi[4] = { 100, 66, 50, 33 };
>
> Duplicate, move to file scope?
>
Agreed.
> > +
> > + if (!(cfg & PIN_CFG_IOLH_B))
> > + return -EINVAL;
> > +
> > + for (i = 0; i < ARRAY_SIZE(oi); i++) {
> > + if (arg == oi[i])
> > + break;
> > + }
> > + if (i >= ARRAY_SIZE(oi))
> > + return -EINVAL;
> > +
> > + spin_lock_irqsave(&pctrl->lock, flags);
> > + addr = pctrl->base + IOLH(port);
> > + rzg2l_rmw_pin_config(addr, bit, IOLH_MASK, (i << (bit * 8)));
>
> Likewise.
>
OK.
> > + spin_unlock_irqrestore(&pctrl->lock, flags);
> > + break;
> > + }
> > +
> > default:
> > return -EOPNOTSUPP;
> > }
>
> The rest looks good to me!
>
Thanks, I'll post a v2 just with patches 3 and 4 only. Hope that is OK with you.
Cheers,
Prabhakar
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
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