static u8 charlcd_4bit_read_char()

in arm-charlcd.c [115:158]

• 31 lines of code
• 6 McCabe index (conditional complexity)

static u8 charlcd_4bit_read_char(struct charlcd *lcd)
{
	u8 data;
	u32 val;
	int i;

	/* If we can, use an IRQ to wait for the data, else poll */
	if (lcd->irq >= 0)
		charlcd_wait_complete_irq(lcd);
	else {
		i = 0;
		val = 0;
		while (!(val & CHAR_RAW_VALID) && i < 10) {
			udelay(100);
			val = readl(lcd->virtbase + CHAR_RAW);
			i++;
		}

		writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
	}
	msleep(1);

	/* Read the 4 high bits of the data */
	data = readl(lcd->virtbase + CHAR_RD) & 0xf0;

	/*
	 * The second read for the low bits does not trigger an IRQ
	 * so in this case we have to poll for the 4 lower bits
	 */
	i = 0;
	val = 0;
	while (!(val & CHAR_RAW_VALID) && i < 10) {
		udelay(100);
		val = readl(lcd->virtbase + CHAR_RAW);
		i++;
	}
	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
	msleep(1);

	/* Read the 4 low bits of the data */
	data |= (readl(lcd->virtbase + CHAR_RD) >> 4) & 0x0f;

	return data;
}