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Commit 4a171fc8 authored by Patrick Daly's avatar Patrick Daly
Browse files

msm: clock-generic: Return best parent_rate from div_round_rate 



Returning only the rounded rate and corresponding divider is not
sufficient. Since these values must be represented as integers, rather
than fractions, their product may not be equal to the actual parent
clock rate necessary.

Change-Id: I16a18595baa6f12d3fb3f7379acc80ee3988b2a3
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 795c7f2e

arch/arm/mach-msm/clock-generic.c

+17 −16
Original line number Diff line number Diff line
@@ -286,10 +286,10 @@ struct clk_mux_ops mux_reg_ops = { 
/* ==================== Divider clock ==================== */



static long __div_round_rate(struct div_data *data, unsigned long rate,

	struct clk *parent, unsigned int *best_div)

	struct clk *parent, unsigned int *best_div, unsigned long *best_prate)

{

	unsigned int div, min_div, max_div, rrate_div = 1;

	unsigned long p_rrate, rrate = 0;

	unsigned int div, min_div, max_div, _best_div = 1;

	unsigned long prate, _best_prate = 0, rrate = 0;



	rate = max(rate, 1UL);
@@ -297,15 +297,14 @@ static long __div_round_rate(struct div_data *data, unsigned long rate, 
	max_div = min(data->max_div, (unsigned int) (ULONG_MAX / rate));



	for (div = min_div; div <= max_div; div++) {

		p_rrate = clk_round_rate(parent, rate * div);

		if (IS_ERR_VALUE(p_rrate))

		prate = clk_round_rate(parent, rate * div);

		if (IS_ERR_VALUE(prate))

			break;



		p_rrate /= div;



		if (is_better_rate(rate, rrate, p_rrate)) {

			rrate = p_rrate;

			rrate_div = div;

		if (is_better_rate(rate, rrate, prate / div)) {

			rrate = prate / div;

			_best_div = div;

			_best_prate = prate;

		}



		/*
@@ -315,7 +314,7 @@ static long __div_round_rate(struct div_data *data, unsigned long rate, 
		 * going to be able to output an even higher rate required

		 * for a higher divider. So, stop trying higher dividers.

		 */

		if (p_rrate < rate)

		if (prate / div < rate)

			break;



		if (rrate <= rate + data->rate_margin)
@@ -325,7 +324,9 @@ static long __div_round_rate(struct div_data *data, unsigned long rate, 
	if (!rrate)

		return -EINVAL;

	if (best_div)

		*best_div = rrate_div;

		*best_div = _best_div;

	if (best_prate)

		*best_prate = _best_prate;



	return rrate;

}
@@ -334,17 +335,17 @@ static long div_round_rate(struct clk *c, unsigned long rate) 
{

	struct div_clk *d = to_div_clk(c);



	return __div_round_rate(&d->data, rate, c->parent, NULL);

	return __div_round_rate(&d->data, rate, c->parent, NULL, NULL);

}



static int div_set_rate(struct clk *c, unsigned long rate)

{

	struct div_clk *d = to_div_clk(c);

	int div, rc = 0;

	long rrate, old_prate;

	long rrate, old_prate, new_prate;

	struct div_data *data = &d->data;



	rrate = __div_round_rate(data, rate, c->parent, &div);

	rrate = __div_round_rate(data, rate, c->parent, &div, &new_prate);

	if (rrate != rate)

		return -EINVAL;
@@ -360,7 +361,7 @@ static int div_set_rate(struct clk *c, unsigned long rate) 
		return rc;



	old_prate = clk_get_rate(c->parent);

	rc = clk_set_rate(c->parent, rate * div);

	rc = clk_set_rate(c->parent, new_prate);

	if (rc)

		goto set_rate_fail;