mirror of https://gitee.com/openkylin/linux.git
128 lines
2.8 KiB
C
128 lines
2.8 KiB
C
/*
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* Copyright (C) 2016 Free Electrons
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* Copyright (C) 2016 NextThing Co
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*/
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#include <linux/clk-provider.h>
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#include "sun4i_tcon.h"
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#include "sun4i_hdmi.h"
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struct sun4i_ddc {
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struct clk_hw hw;
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struct sun4i_hdmi *hdmi;
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};
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static inline struct sun4i_ddc *hw_to_ddc(struct clk_hw *hw)
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{
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return container_of(hw, struct sun4i_ddc, hw);
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}
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static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
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unsigned long parent_rate,
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u8 *m, u8 *n)
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{
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unsigned long best_rate = 0;
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u8 best_m = 0, best_n = 0, _m, _n;
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for (_m = 0; _m < 8; _m++) {
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for (_n = 0; _n < 8; _n++) {
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unsigned long tmp_rate;
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tmp_rate = (((parent_rate / 2) / 10) >> _n) / (_m + 1);
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if (tmp_rate > rate)
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continue;
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if (abs(rate - tmp_rate) < abs(rate - best_rate)) {
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best_rate = tmp_rate;
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best_m = _m;
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best_n = _n;
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}
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}
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}
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if (m && n) {
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*m = best_m;
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*n = best_n;
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}
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return best_rate;
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}
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static long sun4i_ddc_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *prate)
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{
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return sun4i_ddc_calc_divider(rate, *prate, NULL, NULL);
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}
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static unsigned long sun4i_ddc_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct sun4i_ddc *ddc = hw_to_ddc(hw);
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u32 reg;
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u8 m, n;
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reg = readl(ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
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m = (reg >> 3) & 0x7;
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n = reg & 0x7;
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return (((parent_rate / 2) / 10) >> n) / (m + 1);
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}
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static int sun4i_ddc_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct sun4i_ddc *ddc = hw_to_ddc(hw);
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u8 div_m, div_n;
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sun4i_ddc_calc_divider(rate, parent_rate, &div_m, &div_n);
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writel(SUN4I_HDMI_DDC_CLK_M(div_m) | SUN4I_HDMI_DDC_CLK_N(div_n),
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ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
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return 0;
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}
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static const struct clk_ops sun4i_ddc_ops = {
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.recalc_rate = sun4i_ddc_recalc_rate,
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.round_rate = sun4i_ddc_round_rate,
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.set_rate = sun4i_ddc_set_rate,
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};
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int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *parent)
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{
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struct clk_init_data init;
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struct sun4i_ddc *ddc;
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const char *parent_name;
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parent_name = __clk_get_name(parent);
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if (!parent_name)
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return -ENODEV;
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ddc = devm_kzalloc(hdmi->dev, sizeof(*ddc), GFP_KERNEL);
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if (!ddc)
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return -ENOMEM;
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init.name = "hdmi-ddc";
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init.ops = &sun4i_ddc_ops;
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init.parent_names = &parent_name;
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init.num_parents = 1;
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ddc->hdmi = hdmi;
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ddc->hw.init = &init;
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hdmi->ddc_clk = devm_clk_register(hdmi->dev, &ddc->hw);
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if (IS_ERR(hdmi->ddc_clk))
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return PTR_ERR(hdmi->ddc_clk);
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return 0;
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}
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