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path: root/drivers/gpu/drm/sun4i/sun4i_dotclock.c
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Diffstat (limited to 'drivers/gpu/drm/sun4i/sun4i_dotclock.c')
-rw-r--r--drivers/gpu/drm/sun4i/sun4i_dotclock.c206
1 files changed, 206 insertions, 0 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_dotclock.c b/drivers/gpu/drm/sun4i/sun4i_dotclock.c
new file mode 100644
index 000000000..417ade3d2
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_dotclock.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016 Free Electrons
+ * Copyright (C) 2016 NextThing Co
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+
+#include "sun4i_tcon.h"
+#include "sun4i_dotclock.h"
+
+struct sun4i_dclk {
+ struct clk_hw hw;
+ struct regmap *regmap;
+ struct sun4i_tcon *tcon;
+};
+
+static inline struct sun4i_dclk *hw_to_dclk(struct clk_hw *hw)
+{
+ return container_of(hw, struct sun4i_dclk, hw);
+}
+
+static void sun4i_dclk_disable(struct clk_hw *hw)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+
+ regmap_update_bits(dclk->regmap, SUN4I_TCON0_DCLK_REG,
+ BIT(SUN4I_TCON0_DCLK_GATE_BIT), 0);
+}
+
+static int sun4i_dclk_enable(struct clk_hw *hw)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+
+ return regmap_update_bits(dclk->regmap, SUN4I_TCON0_DCLK_REG,
+ BIT(SUN4I_TCON0_DCLK_GATE_BIT),
+ BIT(SUN4I_TCON0_DCLK_GATE_BIT));
+}
+
+static int sun4i_dclk_is_enabled(struct clk_hw *hw)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+ u32 val;
+
+ regmap_read(dclk->regmap, SUN4I_TCON0_DCLK_REG, &val);
+
+ return val & BIT(SUN4I_TCON0_DCLK_GATE_BIT);
+}
+
+static unsigned long sun4i_dclk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+ u32 val;
+
+ regmap_read(dclk->regmap, SUN4I_TCON0_DCLK_REG, &val);
+
+ val >>= SUN4I_TCON0_DCLK_DIV_SHIFT;
+ val &= (1 << SUN4I_TCON0_DCLK_DIV_WIDTH) - 1;
+
+ if (!val)
+ val = 1;
+
+ return parent_rate / val;
+}
+
+static long sun4i_dclk_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+ struct sun4i_tcon *tcon = dclk->tcon;
+ unsigned long best_parent = 0;
+ u8 best_div = 1;
+ int i;
+
+ for (i = tcon->dclk_min_div; i <= tcon->dclk_max_div; i++) {
+ u64 ideal = (u64)rate * i;
+ unsigned long rounded;
+
+ /*
+ * ideal has overflowed the max value that can be stored in an
+ * unsigned long, and every clk operation we might do on a
+ * truncated u64 value will give us incorrect results.
+ * Let's just stop there since bigger dividers will result in
+ * the same overflow issue.
+ */
+ if (ideal > ULONG_MAX)
+ goto out;
+
+ rounded = clk_hw_round_rate(clk_hw_get_parent(hw),
+ ideal);
+
+ if (rounded == ideal) {
+ best_parent = rounded;
+ best_div = i;
+ goto out;
+ }
+
+ if (abs(rate - rounded / i) <
+ abs(rate - best_parent / best_div)) {
+ best_parent = rounded;
+ best_div = i;
+ }
+ }
+
+out:
+ *parent_rate = best_parent;
+
+ return best_parent / best_div;
+}
+
+static int sun4i_dclk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+ u8 div = parent_rate / rate;
+
+ return regmap_update_bits(dclk->regmap, SUN4I_TCON0_DCLK_REG,
+ GENMASK(6, 0), div);
+}
+
+static int sun4i_dclk_get_phase(struct clk_hw *hw)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+ u32 val;
+
+ regmap_read(dclk->regmap, SUN4I_TCON0_IO_POL_REG, &val);
+
+ val >>= 28;
+ val &= 3;
+
+ return val * 120;
+}
+
+static int sun4i_dclk_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct sun4i_dclk *dclk = hw_to_dclk(hw);
+ u32 val = degrees / 120;
+
+ val <<= 28;
+
+ regmap_update_bits(dclk->regmap, SUN4I_TCON0_IO_POL_REG,
+ GENMASK(29, 28),
+ val);
+
+ return 0;
+}
+
+static const struct clk_ops sun4i_dclk_ops = {
+ .disable = sun4i_dclk_disable,
+ .enable = sun4i_dclk_enable,
+ .is_enabled = sun4i_dclk_is_enabled,
+
+ .recalc_rate = sun4i_dclk_recalc_rate,
+ .round_rate = sun4i_dclk_round_rate,
+ .set_rate = sun4i_dclk_set_rate,
+
+ .get_phase = sun4i_dclk_get_phase,
+ .set_phase = sun4i_dclk_set_phase,
+};
+
+int sun4i_dclk_create(struct device *dev, struct sun4i_tcon *tcon)
+{
+ const char *clk_name, *parent_name;
+ struct clk_init_data init;
+ struct sun4i_dclk *dclk;
+ int ret;
+
+ parent_name = __clk_get_name(tcon->sclk0);
+ ret = of_property_read_string_index(dev->of_node,
+ "clock-output-names", 0,
+ &clk_name);
+ if (ret)
+ return ret;
+
+ dclk = devm_kzalloc(dev, sizeof(*dclk), GFP_KERNEL);
+ if (!dclk)
+ return -ENOMEM;
+ dclk->tcon = tcon;
+
+ init.name = clk_name;
+ init.ops = &sun4i_dclk_ops;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ init.flags = CLK_SET_RATE_PARENT;
+
+ dclk->regmap = tcon->regs;
+ dclk->hw.init = &init;
+
+ tcon->dclk = clk_register(dev, &dclk->hw);
+ if (IS_ERR(tcon->dclk))
+ return PTR_ERR(tcon->dclk);
+
+ return 0;
+}
+EXPORT_SYMBOL(sun4i_dclk_create);
+
+int sun4i_dclk_free(struct sun4i_tcon *tcon)
+{
+ clk_unregister(tcon->dclk);
+ return 0;
+}
+EXPORT_SYMBOL(sun4i_dclk_free);