Re: [PATCH v7 1/4] gpiolib: Pass bitmaps, not integer arrays, to get/set array

Matthew Wilcox
2018-09-03T04:31:57Z

> +++ b/drivers/auxdisplay/hd44780.c
> @@ -62,17 +62,12 @@ static void hd44780_strobe_gpio(struct hd44780 *hd)
> /* write to an LCD panel register in 8 bit GPIO mode */
> static void hd44780_write_gpio8(struct hd44780 *hd, u8 val, unsigned int rs)
> {
> - int values[10]; /* for DATA[0-7], RS, RW */
> - unsigned int i, n;
> -
> - for (i = 0; i < 8; i++)
> - values[PIN_DATA0 + i] = !!(val & BIT(i));
> - values[PIN_CTRL_RS] = rs;
> - n = 9;
> - if (hd->pins[PIN_CTRL_RW]) {
> - values[PIN_CTRL_RW] = 0;
> - n++;
> - }
> + DECLARE_BITMAP(values, 10); /* for DATA[0-7], RS, RW */
> + unsigned int n;
> +
> + *values = val;
> + __assign_bit(8, values, rs);
> + n = hd->pins[PIN_CTRL_RW] ? 10 : 9;

Doesn't this assume little endian bitmaps? Has anyone tested this on
big-endian machines?