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Date: Sun, 2 Sep 2018 21:31:29 -0700
From: Matthew Wilcox <willy@infradead.org>
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Subject: Re: [PATCH v7 1/4] gpiolib: Pass bitmaps, not integer arrays, to
 get/set array
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> +++ 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?