From 71c7a2d675c8fe9b6ab284dcf586f30a7109c96c Mon Sep 17 00:00:00 2001 From: Oder Chiou Date: Tue, 20 May 2014 15:01:54 +0800 Subject: ASoC: rt5640: Add the function of the PLL clock calculation to RL6231 shared support The patch adds the function of the PLL clock calculation to RL6231 shared support. Signed-off-by: Oder Chiou Signed-off-by: Mark Brown --- sound/soc/codecs/rl6231.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) (limited to 'sound/soc/codecs/rl6231.c') diff --git a/sound/soc/codecs/rl6231.c b/sound/soc/codecs/rl6231.c index 13ac551..289024b 100644 --- a/sound/soc/codecs/rl6231.c +++ b/sound/soc/codecs/rl6231.c @@ -62,6 +62,75 @@ int rl6231_calc_dmic_clk(int rate) } EXPORT_SYMBOL_GPL(rl6231_calc_dmic_clk); +/** + * rl6231_pll_calc - Calcualte PLL M/N/K code. + * @freq_in: external clock provided to codec. + * @freq_out: target clock which codec works on. + * @pll_code: Pointer to structure with M, N, K and bypass flag. + * + * Calcualte M/N/K code to configure PLL for codec. + * + * Returns 0 for success or negative error code. + */ +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 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); + bool bypass = false; + + if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in) + return -EINVAL; + + k = 100000000 / freq_out - 2; + if (k > RL6231_PLL_K_MAX) + k = RL6231_PLL_K_MAX; + for (n_t = 0; n_t <= max_n; n_t++) { + in_t = freq_in / (k + 2); + pll_out = freq_out / (n_t + 2); + if (in_t < 0) + continue; + if (in_t == pll_out) { + bypass = true; + n = n_t; + goto code_find; + } + red = abs(in_t - pll_out); + if (red < red_t) { + bypass = true; + n = n_t; + m = m_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); + if (red < red_t) { + bypass = false; + n = n_t; + m = m_t; + if (red == 0) + goto code_find; + red_t = red; + } + } + } + pr_debug("Only get approximation about PLL\n"); + +code_find: + + pll_code->m_bp = bypass; + pll_code->m_code = m; + pll_code->n_code = n; + pll_code->k_code = k; + return 0; +} +EXPORT_SYMBOL_GPL(rl6231_pll_calc); + MODULE_DESCRIPTION("RL6231 class device shared support"); MODULE_AUTHOR("Oder Chiou "); MODULE_LICENSE("GPL v2"); -- cgit v1.1