[PATCH v6 3/9] clk: meson: add vclk driver

[Neil Armstrong]

The VCLK and VCLK_DIV clocks have supplementary bits.

The VCLK has a "SOFT RESET" bit to toggle after the whole
VCLK sub-tree rate has been set, this is implemented in
the gate enable callback.

The VCLK_DIV clocks as enable and reset bits used to disable
and reset the divider, associated with CLK_SET_RATE_GATE it ensures
the rate is set while the divider is disabled and in reset mode.

The VCLK_DIV enable bit isn't implemented as a gate since it's part
of the divider logic and vendor does this exact sequence to ensure
the divider is correctly set.

Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
 drivers/clk/meson/Kconfig  |   5 ++
 drivers/clk/meson/Makefile |   1 +
 drivers/clk/meson/vclk.c   | 146 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/meson/vclk.h   |  68 +++++++++++++++++++++
 4 files changed, 220 insertions(+)

diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
index 135da8f2d0b1..83f629515e96 100644
--- a/drivers/clk/meson/Kconfig
+++ b/drivers/clk/meson/Kconfig
@@ -30,6 +30,10 @@ config COMMON_CLK_MESON_VID_PLL_DIV
 	tristate
 	select COMMON_CLK_MESON_REGMAP
 
+config COMMON_CLK_MESON_VCLK
+	tristate
+	select COMMON_CLK_MESON_REGMAP
+
 config COMMON_CLK_MESON_CLKC_UTILS
 	tristate
 
@@ -140,6 +144,7 @@ config COMMON_CLK_G12A
 	select COMMON_CLK_MESON_EE_CLKC
 	select COMMON_CLK_MESON_CPU_DYNDIV
 	select COMMON_CLK_MESON_VID_PLL_DIV
+	select COMMON_CLK_MESON_VCLK
 	select MFD_SYSCON
 	help
 	  Support for the clock controller on Amlogic S905D2, S905X2 and S905Y2
diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index cd961cc4f4db..6efeb8c7bd2a 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_COMMON_CLK_MESON_PLL) += clk-pll.o
 obj-$(CONFIG_COMMON_CLK_MESON_REGMAP) += clk-regmap.o
 obj-$(CONFIG_COMMON_CLK_MESON_SCLK_DIV) += sclk-div.o
 obj-$(CONFIG_COMMON_CLK_MESON_VID_PLL_DIV) += vid-pll-div.o
+obj-$(CONFIG_COMMON_CLK_MESON_VCLK) += vclk.o
 
 # Amlogic Clock controllers
 
diff --git a/drivers/clk/meson/vclk.c b/drivers/clk/meson/vclk.c
new file mode 100644
index 000000000000..0df84403b17f
--- /dev/null
+++ b/drivers/clk/meson/vclk.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Neil Armstrong <neil.armstrong@xxxxxxxxxx>
+ */
+
+#include <linux/module.h>
+#include "vclk.h"
+
+/* The VCLK gate has a supplementary reset bit to pulse after ungating */
+
+static int clk_regmap_vclk_enable(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_data *vclk = clk_get_regmap_vclk_data(clk);
+
+	regmap_set_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
+
+	/* Do a reset pulse */
+	regmap_set_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
+	regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
+
+	return 0;
+}
+
+static void clk_regmap_vclk_disable(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_data *vclk = clk_get_regmap_vclk_data(clk);
+
+	regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
+}
+
+static int clk_regmap_vclk_is_enabled(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_data *vclk = clk_get_regmap_vclk_data(clk);
+	unsigned int val;
+
+	regmap_read(clk->map, vclk->offset, &val);
+
+	return val & BIT(vclk->enable_bit_idx) ? 1 : 0;
+}
+
+const struct clk_ops clk_regmap_vclk_ops = {
+	.enable = clk_regmap_vclk_enable,
+	.disable = clk_regmap_vclk_disable,
+	.is_enabled = clk_regmap_vclk_is_enabled,
+};
+EXPORT_SYMBOL_GPL(clk_regmap_vclk_ops);
+
+/* The VCLK Divider has supplementary reset & enable bits */
+
+static unsigned long clk_regmap_vclk_div_recalc_rate(struct clk_hw *hw,
+						     unsigned long prate)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(clk->map, vclk->offset, &val);
+	if (ret)
+		/* Gives a hint that something is wrong */
+		return 0;
+
+	val >>= vclk->shift;
+	val &= clk_div_mask(vclk->width);
+
+	return divider_recalc_rate(hw, prate, val, vclk->table, vclk->flags,
+				   vclk->width);
+}
+
+static int clk_regmap_vclk_div_determine_rate(struct clk_hw *hw,
+					      struct clk_rate_request *req)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
+
+	return divider_determine_rate(hw, req, vclk->table, vclk->width,
+				      vclk->flags);
+}
+
+static int clk_regmap_vclk_div_set_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long parent_rate)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
+	unsigned int val;
+	int ret;
+
+	ret = divider_get_val(rate, parent_rate, vclk->table, vclk->width,
+			      vclk->flags);
+	if (ret < 0)
+		return ret;
+
+	val = (unsigned int)ret << vclk->shift;
+	return regmap_update_bits(clk->map, vclk->offset,
+				  clk_div_mask(vclk->width) << vclk->shift, val);
+};
+
+static int clk_regmap_vclk_div_enable(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
+
+	/* Unreset the divider when ungating */
+	regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
+
+	return regmap_set_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
+}
+
+static void clk_regmap_vclk_div_disable(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
+
+	/* Reset the divider when gating */
+	regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
+
+	regmap_set_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
+}
+
+static int clk_regmap_vclk_div_is_enabled(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
+	unsigned int val;
+
+	regmap_read(clk->map, vclk->offset, &val);
+
+	return val & BIT(vclk->enable_bit_idx) ? 1 : 0;
+}
+
+const struct clk_ops clk_regmap_vclk_div_ops = {
+	.recalc_rate = clk_regmap_vclk_div_recalc_rate,
+	.determine_rate = clk_regmap_vclk_div_determine_rate,
+	.set_rate = clk_regmap_vclk_div_set_rate,
+	.enable = clk_regmap_vclk_div_enable,
+	.disable = clk_regmap_vclk_div_disable,
+	.is_enabled = clk_regmap_vclk_div_is_enabled,
+};
+EXPORT_SYMBOL_GPL(clk_regmap_vclk_div_ops);
+
+MODULE_DESCRIPTION("Amlogic vclk clock driver");
+MODULE_AUTHOR("Neil Armstrong <neil.armstrong@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/clk/meson/vclk.h b/drivers/clk/meson/vclk.h
new file mode 100644
index 000000000000..90786552a7f3
--- /dev/null
+++ b/drivers/clk/meson/vclk.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2023 Neil Armstrong <neil.armstrong@xxxxxxxxxx>
+ */
+
+#ifndef __VCLK_H
+#define __VCLK_H
+
+#include "clk-regmap.h"
+
+/**
+ * struct clk_regmap_vclk_data - vclk regmap backed specific data
+ *
+ * @offset:		offset of the register controlling gate
+ * @enable_bit_idx:	single bit controlling vclk enable
+ * @reset_bit_idx:	single bit controlling vclk reset
+ * @flags:		hardware-specific flags
+ *
+ * Flags:
+ * Same as clk_gate except CLK_GATE_HIWORD_MASK which is ignored
+ */
+struct clk_regmap_vclk_data {
+	unsigned int	offset;
+	u8		enable_bit_idx;
+	u8		reset_bit_idx;
+	u8		flags;
+};
+
+static inline struct clk_regmap_vclk_data *
+clk_get_regmap_vclk_data(struct clk_regmap *clk)
+{
+	return (struct clk_regmap_vclk_data *)clk->data;
+}
+
+extern const struct clk_ops clk_regmap_vclk_ops;
+
+/**
+ * struct clk_regmap_vclk_div_data - vclk_div regmap back specific data
+ *
+ * @offset:	offset of the register controlling the divider
+ * @shift:	shift to the divider bit field
+ * @width:	width of the divider bit field
+ * @enable_bit_idx:	single bit controlling vclk divider enable
+ * @reset_bit_idx:	single bit controlling vclk divider reset
+ * @table:	array of value/divider pairs, last entry should have div = 0
+ *
+ * Flags:
+ * Same as clk_divider except CLK_DIVIDER_HIWORD_MASK which is ignored
+ */
+struct clk_regmap_vclk_div_data {
+	unsigned int	offset;
+	u8		shift;
+	u8		width;
+	u8		enable_bit_idx;
+	u8		reset_bit_idx;
+	const struct clk_div_table      *table;
+	u8		flags;
+};
+
+static inline struct clk_regmap_vclk_div_data *
+clk_get_regmap_vclk_div_data(struct clk_regmap *clk)
+{
+	return (struct clk_regmap_vclk_div_data *)clk->data;
+}
+
+extern const struct clk_ops clk_regmap_vclk_div_ops;
+
+#endif /* __VCLK_H */

-- 
2.34.1