Re: [PATCH 4/4] pinctrl: renesas: pinctrl-rzg2l: Add support to get/set drive-strength and output-impedance-ohms
From: Geert Uytterhoeven
Date: Thu Oct 28 2021 - 03:56:38 EST
Hi Prabhakar,
On Wed, Oct 27, 2021 at 3:45 PM Lad Prabhakar
<prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
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.
BTW, where do I find these "VMC" names in the HW manual?
> * 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.
> + 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.
> + void __iomem *addr_adjust = addr;
> + u8 bit_adjust = bit;
No need for these, just operate on addr and bit directly.
> + 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.
> +}
Please split the introduction of these helpers (and add conversion
of the existing PIN_CONFIG_INPUT_ENABLE handling) off into a separate
patch.
> @@ -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?
> + 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?
> +
> + 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:
rzg2l_rmw_pin_config(pctrl, IOLH(port), bit, IOLH_MASK, i);
> + 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?
> +
> + 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.
> + spin_unlock_irqrestore(&pctrl->lock, flags);
> + break;
> + }
> +
> default:
> return -EOPNOTSUPP;
> }
The rest looks good to me!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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