Esempio n. 1
0
static void ar933x_uart_get_scale_step(unsigned int clk,
				       unsigned int baud,
				       unsigned int *scale,
				       unsigned int *step)
{
	unsigned int tscale;
	long min_diff;

	*scale = 0;
	*step = 0;

	min_diff = baud;
	for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
		u64 tstep;
		int diff;

		tstep = baud * (tscale + 1);
		tstep *= (2 << 16);
		do_div(tstep, clk);

		if (tstep > AR933X_UART_MAX_STEP)
			break;

		diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
		if (diff < min_diff) {
			min_diff = diff;
			*scale = tscale;
			*step = tstep;
		}
	}
}
Esempio n. 2
0
/*
 * Calculate the scale/step with the lowest possible deviation from
 * the target baudrate.
 */
static void
ar933x_uart_get_scale_step(struct uart_bas *bas, unsigned int baud,
    unsigned int *scale, unsigned int *step)
{
	unsigned int tscale;
	uint32_t clk;
	long min_diff;

	clk = bas->rclk;
	*scale = 0;
	*step = 0;

	min_diff = baud;
	for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
		uint64_t tstep;
		int diff;

		tstep = baud * (tscale + 1);
		tstep *= (2 << 16);
		tstep = tstep / clk;

		if (tstep > AR933X_UART_MAX_STEP)
			break;

		diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
		if (diff < min_diff) {
			min_diff = diff;
			*scale = tscale;
			*step = tstep;
		}
	}
}