drm/sun4i: Add HDMI support

The earlier Allwinner SoCs (A10, A10s, A20, A31) have an embedded HDMI
controller.

That HDMI controller is able to do audio and CEC, but those have been left
out for now.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

1 files changed, 225 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c
new file mode 100644
index 000000000000..5cf2527bffc8
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_tmds_clk.c
@@ -0,0 +1,225 @@
+/*
+ * 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_tcon.h"
+#include "sun4i_hdmi.h"
+
+struct sun4i_tmds {
+	struct clk_hw		hw;
+	struct sun4i_hdmi	*hdmi;
+};
+
+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,
+					     bool *half)
+{
+	unsigned long best_rate = 0;
+	u8 best_m = 0, m;
+	bool is_double;
+
+	for (m = 1; m < 16; 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;
+			}
+		}
+	}
+
+	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 clk_hw *parent;
+	unsigned long best_parent = 0;
+	unsigned long rate = req->rate;
+	int best_div = 1, best_half = 1;
+	int i, j;
+
+	/*
+	 * 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.
+	 */
+
+	parent = clk_hw_get_parent_by_index(hw, 0);
+	if (!parent)
+		return -EINVAL;
+
+	for (i = 1; i < 3; i++) {
+		for (j = 1; j < 16; 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 (abs(rate - rounded / i) <
+			    abs(rate - best_parent / best_div)) {
+				best_parent = rounded;
+				best_div = i;
+			}
+		}
+	}
+
+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;
+	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, &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->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;
+
+	hdmi->tmds_clk = devm_clk_register(hdmi->dev, &tmds->hw);
+	if (IS_ERR(hdmi->tmds_clk))
+		return PTR_ERR(hdmi->tmds_clk);
+
+	return 0;
+}