[PATCH 2/2] pinctrl: zynqmp: Support muxing individual pins
Andy Shevchenko
andy.shevchenko at gmail.com
Mon May 6 12:26:04 PDT 2024
Fri, May 03, 2024 at 12:22:17PM -0400, Sean Anderson kirjoitti:
> While muxing groups of pins at once can be convenient for large
> interfaces, it can also be rigid. This is because the group is set to
> all pins which support a particular function, even though not all pins
> may be used. For example, the sdhci0 function may be used with a 8-bit
> eMMC, 4-bit SD card, or even a 1-bit SD card. In these cases, the extra
> pins may be repurposed for other uses, but this is not currently
> allowed.
>
> Add a new group for each pin which can be muxed. These groups are part
> of each function the pin can be muxed to. We treat group selectors
> beyond the number of groups as "pin" groups. To set this up, we
> initialize groups before functions, and then create a bitmap of used
> pins for each function. These used pins are appended to the function's
> list of groups.
...
> + for (pin = 0; pin < groups[resp[i]].npins; pin++)
> + set_bit(groups[resp[i]].pins[pin], used_pins);
Why atomic bit operation?
...
> + fgroups = devm_kcalloc(dev, func->ngroups + npins, sizeof(*fgroups),
size_add() from overflow.h.
> + GFP_KERNEL);
> + if (!fgroups)
> + return -ENOMEM;
...
> + for (i = 0; i < func->ngroups; i++) {
> + fgroups[i] = devm_kasprintf(dev, GFP_KERNEL, "%s_%d_grp",
> + func->name, i);
> + if (!fgroups[i])
> + return -ENOMEM;
> + }
Hmm... Can this benefit from devm_kasprintf_strarray()?
--
With Best Regards,
Andy Shevchenko
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