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/*
* Copyright (C) 2016 Free Electrons
* Copyright (C) 2016 NextThing Co
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*/
#include <linux/clk-provider.h>
#include "sun4i_hdmi.h"
struct sun4i_tmds {
struct clk_hw hw;
struct sun4i_hdmi *hdmi;
u8 div_offset;
};
static inline struct sun4i_tmds *hw_to_tmds(struct clk_hw *hw)
{
return container_of(hw, struct sun4i_tmds, hw);
}
static unsigned long sun4i_tmds_calc_divider(unsigned long rate,
unsigned long parent_rate,
u8 div_offset,
u8 *div,
bool *half)
{
unsigned long best_rate = 0;
u8 best_m = 0, m;
bool is_double;
for (m = div_offset ?: 1; m < (16 + div_offset); m++) {
u8 d;
for (d = 1; d < 3; d++) {
unsigned long tmp_rate;
tmp_rate = parent_rate / m / d;
if (tmp_rate > rate)
continue;
if (!best_rate ||
(rate - tmp_rate) < (rate - best_rate)) {
best_rate = tmp_rate;
best_m = m;
is_double = (d == 2) ? true : false;
}
}
}
if (div && half) {
*div = best_m;
*half = is_double;
}
return best_rate;
}
static int sun4i_tmds_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct sun4i_tmds *tmds = hw_to_tmds(hw);
struct clk_hw *parent = NULL;
unsigned long best_parent = 0;
unsigned long rate = req->rate;
int best_div = 1, best_half = 1;
int i, j, p;
/*
* We only consider PLL3, since the TCON is very likely to be
* clocked from it, and to have the same rate than our HDMI
* clock, so we should not need to do anything.
*/
for (p = 0; p < clk_hw_get_num_parents(hw); p++) {
parent = clk_hw_get_parent_by_index(hw, p);
if (!parent)
continue;
for (i = 1; i < 3; i++) {
for (j = tmds->div_offset ?: 1;
j < (16 + tmds->div_offset); j++) {
unsigned long ideal = rate * i * j;
unsigned long rounded;
rounded = clk_hw_round_rate(parent, ideal);
if (rounded == ideal) {
best_parent = rounded;
best_half = i;
best_div = j;
goto out;
}
if (!best_parent ||
abs(rate - rounded / i / j) <
abs(rate - best_parent / best_half /
best_div)) {
best_parent = rounded;
best_half = i;
best_div = j;
}
}
}
}
if (!parent)
return -EINVAL;
out:
req->rate = best_parent / best_half / best_div;
req->best_parent_rate = best_parent;
req->best_parent_hw = parent;
return 0;
}
static unsigned long sun4i_tmds_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct sun4i_tmds *tmds = hw_to_tmds(hw);
u32 reg;
reg = readl(tmds->hdmi->base + SUN4I_HDMI_PAD_CTRL1_REG);
if (reg & SUN4I_HDMI_PAD_CTRL1_HALVE_CLK)
parent_rate /= 2;
reg = readl(tmds->hdmi->base + SUN4I_HDMI_PLL_CTRL_REG);
reg = ((reg >> 4) & 0xf) + tmds->div_offset;
if (!reg)
reg = 1;
return parent_rate / reg;
}
static int sun4i_tmds_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct sun4i_tmds *tmds = hw_to_tmds(hw);
bool half;
u32 reg;
u8 div;
sun4i_tmds_calc_divider(rate, parent_rate, tmds->div_offset,
&div, &half);
reg = readl(tmds->hdmi->base + SUN4I_HDMI_PAD_CTRL1_REG);
reg &= ~SUN4I_HDMI_PAD_CTRL1_HALVE_CLK;
if (half)
reg |= SUN4I_HDMI_PAD_CTRL1_HALVE_CLK;
writel(reg, tmds->hdmi->base + SUN4I_HDMI_PAD_CTRL1_REG);
reg = readl(tmds->hdmi->base + SUN4I_HDMI_PLL_CTRL_REG);
reg &= ~SUN4I_HDMI_PLL_CTRL_DIV_MASK;
writel(reg | SUN4I_HDMI_PLL_CTRL_DIV(div - tmds->div_offset),
tmds->hdmi->base + SUN4I_HDMI_PLL_CTRL_REG);
return 0;
}
static u8 sun4i_tmds_get_parent(struct clk_hw *hw)
{
struct sun4i_tmds *tmds = hw_to_tmds(hw);
u32 reg;
reg = readl(tmds->hdmi->base + SUN4I_HDMI_PLL_DBG0_REG);
return ((reg & SUN4I_HDMI_PLL_DBG0_TMDS_PARENT_MASK) >>
SUN4I_HDMI_PLL_DBG0_TMDS_PARENT_SHIFT);
}
static int sun4i_tmds_set_parent(struct clk_hw *hw, u8 index)
{
struct sun4i_tmds *tmds = hw_to_tmds(hw);
u32 reg;
if (index > 1)
return -EINVAL;
reg = readl(tmds->hdmi->base + SUN4I_HDMI_PLL_DBG0_REG);
reg &= ~SUN4I_HDMI_PLL_DBG0_TMDS_PARENT_MASK;
writel(reg | SUN4I_HDMI_PLL_DBG0_TMDS_PARENT(index),
tmds->hdmi->base + SUN4I_HDMI_PLL_DBG0_REG);
return 0;
}
static const struct clk_ops sun4i_tmds_ops = {
.determine_rate = sun4i_tmds_determine_rate,
.recalc_rate = sun4i_tmds_recalc_rate,
.set_rate = sun4i_tmds_set_rate,
.get_parent = sun4i_tmds_get_parent,
.set_parent = sun4i_tmds_set_parent,
};
int sun4i_tmds_create(struct sun4i_hdmi *hdmi)
{
struct clk_init_data init;
struct sun4i_tmds *tmds;
const char *parents[2];
parents[0] = __clk_get_name(hdmi->pll0_clk);
if (!parents[0])
return -ENODEV;
parents[1] = __clk_get_name(hdmi->pll1_clk);
if (!parents[1])
return -ENODEV;
tmds = devm_kzalloc(hdmi->dev, sizeof(*tmds), GFP_KERNEL);
if (!tmds)
return -ENOMEM;
init.name = "hdmi-tmds";
init.ops = &sun4i_tmds_ops;
init.parent_names = parents;
init.num_parents = 2;
init.flags = CLK_SET_RATE_PARENT;
tmds->hdmi = hdmi;
tmds->hw.init = &init;
tmds->div_offset = hdmi->variant->tmds_clk_div_offset;
hdmi->tmds_clk = devm_clk_register(hdmi->dev, &tmds->hw);
if (IS_ERR(hdmi->tmds_clk))
return PTR_ERR(hdmi->tmds_clk);
return 0;
}
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