1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c
new file mode 100644
index 000000000000..4692e8c345ed
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c
@@ -0,0 +1,127 @@
+/*
+ * 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_ddc {
+	struct clk_hw		hw;
+	struct sun4i_hdmi	*hdmi;
+};
+
+static inline struct sun4i_ddc *hw_to_ddc(struct clk_hw *hw)
+{
+	return container_of(hw, struct sun4i_ddc, hw);
+}
+
+static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
+					    unsigned long parent_rate,
+					    u8 *m, u8 *n)
+{
+	unsigned long best_rate = 0;
+	u8 best_m = 0, best_n = 0, _m, _n;
+
+	for (_m = 0; _m < 8; _m++) {
+		for (_n = 0; _n < 8; _n++) {
+			unsigned long tmp_rate;
+
+			tmp_rate = (((parent_rate / 2) / 10) >> _n) / (_m + 1);
+
+			if (tmp_rate > rate)
+				continue;
+
+			if (abs(rate - tmp_rate) < abs(rate - best_rate)) {
+				best_rate = tmp_rate;
+				best_m = _m;
+				best_n = _n;
+			}
+		}
+	}
+
+	if (m && n) {
+		*m = best_m;
+		*n = best_n;
+	}
+
+	return best_rate;
+}
+
+static long sun4i_ddc_round_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long *prate)
+{
+	return sun4i_ddc_calc_divider(rate, *prate, NULL, NULL);
+}
+
+static unsigned long sun4i_ddc_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	struct sun4i_ddc *ddc = hw_to_ddc(hw);
+	u32 reg;
+	u8 m, n;
+
+	reg = readl(ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
+	m = (reg >> 3) & 0x7;
+	n = reg & 0x7;
+
+	return (((parent_rate / 2) / 10) >> n) / (m + 1);
+}
+
+static int sun4i_ddc_set_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct sun4i_ddc *ddc = hw_to_ddc(hw);
+	u8 div_m, div_n;
+
+	sun4i_ddc_calc_divider(rate, parent_rate, &div_m, &div_n);
+
+	writel(SUN4I_HDMI_DDC_CLK_M(div_m) | SUN4I_HDMI_DDC_CLK_N(div_n),
+	       ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
+
+	return 0;
+}
+
+static const struct clk_ops sun4i_ddc_ops = {
+	.recalc_rate	= sun4i_ddc_recalc_rate,
+	.round_rate	= sun4i_ddc_round_rate,
+	.set_rate	= sun4i_ddc_set_rate,
+};
+
+int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *parent)
+{
+	struct clk_init_data init;
+	struct sun4i_ddc *ddc;
+	const char *parent_name;
+
+	parent_name = __clk_get_name(parent);
+	if (!parent_name)
+		return -ENODEV;
+
+	ddc = devm_kzalloc(hdmi->dev, sizeof(*ddc), GFP_KERNEL);
+	if (!ddc)
+		return -ENOMEM;
+
+	init.name = "hdmi-ddc";
+	init.ops = &sun4i_ddc_ops;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	ddc->hdmi = hdmi;
+	ddc->hw.init = &init;
+
+	hdmi->ddc_clk = devm_clk_register(hdmi->dev, &ddc->hw);
+	if (IS_ERR(hdmi->ddc_clk))
+		return PTR_ERR(hdmi->ddc_clk);
+
+	return 0;
+}