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Commit f44b717c authored by Tomi Valkeinen's avatar Tomi Valkeinen
Browse files

drm/omap: add comments for PLL calculations 



Add comments showing how the PLL clock rates are calculated.

Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
parent c107751d

drivers/gpu/drm/omapdrm/dss/pll.c

+7 −0
Original line number Diff line number Diff line
@@ -207,6 +207,10 @@ bool dss_pll_hsdiv_calc_a(const struct dss_pll *pll, unsigned long clkdco, 
	return false;

}



/*

 * clkdco = clkin / n * m * 2

 * clkoutX = clkdco / mX

 */

bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin,

		unsigned long pll_min, unsigned long pll_max,

		dss_pll_calc_func func, void *data)
@@ -252,6 +256,9 @@ bool dss_pll_calc_a(const struct dss_pll *pll, unsigned long clkin, 
 * This calculates a PLL config that will provide the target_clkout rate

 * for clkout. Additionally clkdco rate will be the same as clkout rate

 * when clkout rate is >= min_clkdco.

 *

 * clkdco = clkin / n * m + clkin / n * mf / 262144

 * clkout = clkdco / m2

 */

bool dss_pll_calc_b(const struct dss_pll *pll, unsigned long clkin,

	unsigned long target_clkout, struct dss_pll_clock_info *cinfo)