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Unverified Commit 2f8aab3d authored by Bard Liao's avatar Bard Liao Committed by Mark Brown
Browse files

ASoC: rl6231: get better PLL parameters 



For those which can only get approximation PLL out cases, this patch
will use higher resolution to get a better PLL parameter.

Signed-off-by: default avatarBard Liao <bardliao@realtek.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 4fbd8d19

sound/soc/codecs/rl6231.c

+66 −29
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/module.h>

#include <linux/regmap.h>



#include <linux/gcd.h>

#include "rl6231.h"



/**
@@ -106,6 +107,25 @@ static const struct pll_calc_map pll_preset_table[] = { 
	{19200000,  24576000,  3, 30, 3, false},

};



static unsigned int find_best_div(unsigned int in,

	unsigned int max, unsigned int div)

{

	unsigned int d;



	if (in <= max)

		return 1;



	d = in / max;

	if (in % max)

		d++;



	while (div % d != 0)

		d++;





	return d;

}



/**

 * rl6231_pll_calc - Calcualte PLL M/N/K code.

 * @freq_in: external clock provided to codec.
@@ -120,9 +140,11 @@ int rl6231_pll_calc(const unsigned int freq_in, 
	const unsigned int freq_out, struct rl6231_pll_code *pll_code)

{

	int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;

	int i, k, red, n_t, pll_out, in_t, out_t;

	int n = 0, m = 0, m_t = 0;

	int red_t = abs(freq_out - freq_in);

	int i, k, n_t;

	int k_t, min_k, max_k, n = 0, m = 0, m_t = 0;

	unsigned int red, pll_out, in_t, out_t, div, div_t;

	unsigned int red_t = abs(freq_out - freq_in);

	unsigned int f_in, f_out, f_max;

	bool bypass = false;



	if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
@@ -140,41 +162,56 @@ int rl6231_pll_calc(const unsigned int freq_in, 
		}

	}



	k = 100000000 / freq_out - 2;

	if (k > RL6231_PLL_K_MAX)

		k = RL6231_PLL_K_MAX;

	min_k = 80000000 / freq_out - 2;

	max_k = 150000000 / freq_out - 2;

	if (max_k > RL6231_PLL_K_MAX)

		max_k = RL6231_PLL_K_MAX;

	if (min_k > RL6231_PLL_K_MAX)

		min_k = max_k = RL6231_PLL_K_MAX;

	div_t = gcd(freq_in, freq_out);

	f_max = 0xffffffff / RL6231_PLL_N_MAX;

	div = find_best_div(freq_in, f_max, div_t);

	f_in = freq_in / div;

	f_out = freq_out / div;

	k = min_k;

	for (k_t = min_k; k_t <= max_k; k_t++) {

		for (n_t = 0; n_t <= max_n; n_t++) {

		in_t = freq_in / (k + 2);

		pll_out = freq_out / (n_t + 2);

			in_t = f_in * (n_t + 2);

			pll_out = f_out * (k_t + 2);

			if (in_t < 0)

				continue;

			if (in_t == pll_out) {

				bypass = true;

				n = n_t;

				k = k_t;

				goto code_find;

			}

		red = abs(in_t - pll_out);

			out_t = in_t / (k_t + 2);

			red = abs(f_out - out_t);

			if (red < red_t) {

				bypass = true;

				n = n_t;

			m = m_t;

				m = 0;

				k = k_t;

				if (red == 0)

					goto code_find;

				red_t = red;

			}

			for (m_t = 0; m_t <= max_m; m_t++) {

			out_t = in_t / (m_t + 2);

			red = abs(out_t - pll_out);

				out_t = in_t / ((m_t + 2) * (k_t + 2));

				red = abs(f_out - out_t);

				if (red < red_t) {

					bypass = false;

					n = n_t;

					m = m_t;

					k = k_t;

					if (red == 0)

						goto code_find;

					red_t = red;

				}

			}

		}

	}

	pr_debug("Only get approximation about PLL\n");



code_find: