Thread (33 messages) 33 messages, 6 authors, 2025-06-25

Re: [PATCH v12 1/7] mfd: Add core driver for Nuvoton NCT6694

From: Ming Yu <hidden>
Date: 2025-06-12 14:41:07
Also in: linux-can, linux-gpio, linux-hwmon, linux-i2c, linux-rtc, linux-usb, linux-watchdog, lkml

Dear Lee,

Thank you for reviewing,

Lee Jones [off-list ref] 於 2025年6月12日 週四 下午10:00寫道:
...
quoted
+static const struct mfd_cell nct6694_devs[] = {
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 0),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 1),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 2),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 3),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 4),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 5),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 6),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 7),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 8),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 9),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 10),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 11),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 12),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 13),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 14),
+     MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 15),
+
+     MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 0),
+     MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 1),
+     MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 2),
+     MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 3),
+     MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 4),
+     MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 5),
Why have we gone back to this silly numbering scheme?

What happened to using IDA in the child driver?
In a previous version, I tried to maintain a static IDA in each
sub-driver. However, I didn’t consider the case where multiple NCT6694
devices are bound to the same driver — in that case, the IDs are not
fixed and become unusable for my purpose.

I’ve since realized that using pdev->id avoids the need for cell->id,
so I reverted to the earlier approach.

That said, do you think it would be a better solution to manage all
the IDAs centrally within the driver? For example:
in nct6694.c
struct nct6694 {
    struct device *dev;

    struct ida gpio_ida;
    struct ida i2c_ida;
    struct ida can_ida;
    struct ida wdt_ida;
};

static int nct6694_probe(struct platform_device *pdev)
{
    ida_init(&nct6694->gpio_ida);
    ...
}

in gpio-nct6694.c
static int nct6694_gpio_probe(struct platform_device *pdev)
{
    id = ida_alloc(&nct6694->gpio_ida, GFP_KERNEL);
}


Best regards,
Ming
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