forked from Minki/linux
54e1e06bcf
m divider in DDC clock register is 4 bits wide. Fix that.
Fixes: 9c5681011a ("drm/sun4i: Add HDMI support")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200413095457.1176754-1-jernej.skrabec@siol.net
143 lines
3.0 KiB
C
143 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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#include <linux/clk-provider.h>
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#include <linux/regmap.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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struct regmap_field *reg;
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u8 pre_div;
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u8 m_offset;
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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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const u8 pre_div,
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const u8 m_offset,
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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 < 16; _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 / pre_div) / 10) >> _n) /
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(_m + m_offset);
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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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struct sun4i_ddc *ddc = hw_to_ddc(hw);
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return sun4i_ddc_calc_divider(rate, *prate, ddc->pre_div,
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ddc->m_offset, 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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unsigned int reg;
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u8 m, n;
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regmap_field_read(ddc->reg, ®);
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m = (reg >> 3) & 0xf;
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n = reg & 0x7;
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return (((parent_rate / ddc->pre_div) / 10) >> n) /
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(m + ddc->m_offset);
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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, ddc->pre_div,
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ddc->m_offset, &div_m, &div_n);
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regmap_field_write(ddc->reg,
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SUN4I_HDMI_DDC_CLK_M(div_m) |
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SUN4I_HDMI_DDC_CLK_N(div_n));
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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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ddc->reg = devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
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hdmi->variant->ddc_clk_reg);
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if (IS_ERR(ddc->reg))
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return PTR_ERR(ddc->reg);
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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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ddc->pre_div = hdmi->variant->ddc_clk_pre_divider;
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ddc->m_offset = hdmi->variant->ddc_clk_m_offset;
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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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