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Commit 0a1be867 authored by Jerome Brunet's avatar Jerome Brunet Committed by Neil Armstrong
Browse files

clk: meson: add ROUND_CLOSEST to the pll driver 



Provide an option for the pll driver to round to the rate closest to the
requested rate, instead of systematically rounding down.

This may allow the provided rate to be closer to the requested rate when
rounding up is not an issue

Signed-off-by: default avatarJerome Brunet <jbrunet@baylibre.com>
Signed-off-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
parent c77de0e5

drivers/clk/meson/clk-pll.c

+13 −4
Original line number Diff line number Diff line
@@ -105,7 +105,12 @@ static u16 __pll_params_with_frac(unsigned long rate, 
	u64 val = (u64)rate * pllt->n;



	val <<= pllt->od + pllt->od2 + pllt->od3;



	if (pll->flags & CLK_MESON_PLL_ROUND_CLOSEST)

		val = DIV_ROUND_CLOSEST_ULL(val * frac_max, parent_rate);

	else

		val = div_u64(val * frac_max, parent_rate);



	val -= pllt->m * frac_max;



	return min((u16)val, (u16)(frac_max - 1));
@@ -125,9 +130,13 @@ meson_clk_get_pll_settings(unsigned long rate, 
	while (table[i].rate && table[i].rate <= rate)

		i++;



	/* Select the setting of the rounded down rate */

	if (i != 0)

	if (i != 0) {

		if (MESON_PARM_APPLICABLE(&pll->frac) ||

		    !(pll->flags & CLK_MESON_PLL_ROUND_CLOSEST) ||

		    (abs(rate - table[i - 1].rate) <

		     abs(rate - table[i].rate)))

			i--;

	}



	return (struct pll_rate_table *)&table[i];

}

drivers/clk/meson/clkc.h

+2 −0
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ struct pll_rate_table { 
		.od		= (_od),				\

	}



#define CLK_MESON_PLL_ROUND_CLOSEST	BIT(0)



struct meson_clk_pll_data {

	struct parm m;

	struct parm n;