clk: ingenic: add driver for Ingenic SoC CGU clocks

This driver supports the CGU clocks for Ingenic SoCs. It is generic
enough to be usable across at least the JZ4740 to the JZ4780, and will
be made use of on such devices in subsequent commits. This patch by
itself only adds the SoC-agnostic infrastructure that forms the bulk of
the CGU driver for the aforementioned further commits to make use of.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Co-authored-by: Paul Cercueil <paul@crapouillou.net>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-clk@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10150/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 223 insertions, 0 deletions

diff --git a/drivers/clk/ingenic/cgu.h b/drivers/clk/ingenic/cgu.h
new file mode 100644
index 000000000000..99347e2b97e8
--- /dev/null
+++ b/drivers/clk/ingenic/cgu.h
@@ -0,0 +1,223 @@
+/*
+ * Ingenic SoC CGU driver
+ *
+ * Copyright (c) 2013-2015 Imagination Technologies
+ * Author: Paul Burton <paul.burton@imgtec.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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __DRIVERS_CLK_INGENIC_CGU_H__
+#define __DRIVERS_CLK_INGENIC_CGU_H__
+
+#include <linux/bitops.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+
+/**
+ * struct ingenic_cgu_pll_info - information about a PLL
+ * @reg: the offset of the PLL's control register within the CGU
+ * @m_shift: the number of bits to shift the multiplier value by (ie. the
+ *           index of the lowest bit of the multiplier value in the PLL's
+ *           control register)
+ * @m_bits: the size of the multiplier field in bits
+ * @m_offset: the multiplier value which encodes to 0 in the PLL's control
+ *            register
+ * @n_shift: the number of bits to shift the divider value by (ie. the
+ *           index of the lowest bit of the divider value in the PLL's
+ *           control register)
+ * @n_bits: the size of the divider field in bits
+ * @n_offset: the divider value which encodes to 0 in the PLL's control
+ *            register
+ * @od_shift: the number of bits to shift the post-VCO divider value by (ie.
+ *            the index of the lowest bit of the post-VCO divider value in
+ *            the PLL's control register)
+ * @od_bits: the size of the post-VCO divider field in bits
+ * @od_max: the maximum post-VCO divider value
+ * @od_encoding: a pointer to an array mapping post-VCO divider values to
+ *               their encoded values in the PLL control register, or -1 for
+ *               unsupported values
+ * @bypass_bit: the index of the bypass bit in the PLL control register
+ * @enable_bit: the index of the enable bit in the PLL control register
+ * @stable_bit: the index of the stable bit in the PLL control register
+ */
+struct ingenic_cgu_pll_info {
+	unsigned reg;
+	const s8 *od_encoding;
+	u8 m_shift, m_bits, m_offset;
+	u8 n_shift, n_bits, n_offset;
+	u8 od_shift, od_bits, od_max;
+	u8 bypass_bit;
+	u8 enable_bit;
+	u8 stable_bit;
+};
+
+/**
+ * struct ingenic_cgu_mux_info - information about a clock mux
+ * @reg: offset of the mux control register within the CGU
+ * @shift: number of bits to shift the mux value by (ie. the index of
+ *         the lowest bit of the mux value within its control register)
+ * @bits: the size of the mux value in bits
+ */
+struct ingenic_cgu_mux_info {
+	unsigned reg;
+	u8 shift;
+	u8 bits;
+};
+
+/**
+ * struct ingenic_cgu_div_info - information about a divider
+ * @reg: offset of the divider control register within the CGU
+ * @shift: number of bits to shift the divide value by (ie. the index of
+ *         the lowest bit of the divide value within its control register)
+ * @bits: the size of the divide value in bits
+ * @ce_bit: the index of the change enable bit within reg, or -1 if there
+ *          isn't one
+ * @busy_bit: the index of the busy bit within reg, or -1 if there isn't one
+ * @stop_bit: the index of the stop bit within reg, or -1 if there isn't one
+ */
+struct ingenic_cgu_div_info {
+	unsigned reg;
+	u8 shift;
+	u8 bits;
+	s8 ce_bit;
+	s8 busy_bit;
+	s8 stop_bit;
+};
+
+/**
+ * struct ingenic_cgu_fixdiv_info - information about a fixed divider
+ * @div: the divider applied to the parent clock
+ */
+struct ingenic_cgu_fixdiv_info {
+	unsigned div;
+};
+
+/**
+ * struct ingenic_cgu_gate_info - information about a clock gate
+ * @reg: offset of the gate control register within the CGU
+ * @bit: offset of the bit in the register that controls the gate
+ */
+struct ingenic_cgu_gate_info {
+	unsigned reg;
+	u8 bit;
+};
+
+/**
+ * struct ingenic_cgu_custom_info - information about a custom (SoC) clock
+ * @clk_ops: custom clock operation callbacks
+ */
+struct ingenic_cgu_custom_info {
+	struct clk_ops *clk_ops;
+};
+
+/**
+ * struct ingenic_cgu_clk_info - information about a clock
+ * @name: name of the clock
+ * @type: a bitmask formed from CGU_CLK_* values
+ * @parents: an array of the indices of potential parents of this clock
+ *           within the clock_info array of the CGU, or -1 in entries
+ *           which correspond to no valid parent
+ * @pll: information valid if type includes CGU_CLK_PLL
+ * @gate: information valid if type includes CGU_CLK_GATE
+ * @mux: information valid if type includes CGU_CLK_MUX
+ * @div: information valid if type includes CGU_CLK_DIV
+ * @fixdiv: information valid if type includes CGU_CLK_FIXDIV
+ * @custom: information valid if type includes CGU_CLK_CUSTOM
+ */
+struct ingenic_cgu_clk_info {
+	const char *name;
+
+	enum {
+		CGU_CLK_NONE		= 0,
+		CGU_CLK_EXT		= BIT(0),
+		CGU_CLK_PLL		= BIT(1),
+		CGU_CLK_GATE		= BIT(2),
+		CGU_CLK_MUX		= BIT(3),
+		CGU_CLK_MUX_GLITCHFREE	= BIT(4),
+		CGU_CLK_DIV		= BIT(5),
+		CGU_CLK_FIXDIV		= BIT(6),
+		CGU_CLK_CUSTOM		= BIT(7),
+	} type;
+
+	int parents[4];
+
+	union {
+		struct ingenic_cgu_pll_info pll;
+
+		struct {
+			struct ingenic_cgu_gate_info gate;
+			struct ingenic_cgu_mux_info mux;
+			struct ingenic_cgu_div_info div;
+			struct ingenic_cgu_fixdiv_info fixdiv;
+		};
+
+		struct ingenic_cgu_custom_info custom;
+	};
+};
+
+/**
+ * struct ingenic_cgu - data about the CGU
+ * @np: the device tree node that caused the CGU to be probed
+ * @base: the ioremap'ed base address of the CGU registers
+ * @clock_info: an array containing information about implemented clocks
+ * @clocks: used to provide clocks to DT, allows lookup of struct clk*
+ * @lock: lock to be held whilst manipulating CGU registers
+ */
+struct ingenic_cgu {
+	struct device_node *np;
+	void __iomem *base;
+
+	const struct ingenic_cgu_clk_info *clock_info;
+	struct clk_onecell_data clocks;
+
+	spinlock_t lock;
+};
+
+/**
+ * struct ingenic_clk - private data for a clock
+ * @hw: see Documentation/clk.txt
+ * @cgu: a pointer to the CGU data
+ * @idx: the index of this clock in cgu->clock_info
+ */
+struct ingenic_clk {
+	struct clk_hw hw;
+	struct ingenic_cgu *cgu;
+	unsigned idx;
+};
+
+#define to_ingenic_clk(_hw) container_of(_hw, struct ingenic_clk, hw)
+
+/**
+ * ingenic_cgu_new() - create a new CGU instance
+ * @clock_info: an array of clock information structures describing the clocks
+ *              which are implemented by the CGU
+ * @num_clocks: the number of entries in clock_info
+ * @np: the device tree node which causes this CGU to be probed
+ *
+ * Return: a pointer to the CGU instance if initialisation is successful,
+ *         otherwise NULL.
+ */
+struct ingenic_cgu *
+ingenic_cgu_new(const struct ingenic_cgu_clk_info *clock_info,
+		unsigned num_clocks, struct device_node *np);
+
+/**
+ * ingenic_cgu_register_clocks() - Registers the clocks
+ * @cgu: pointer to cgu data
+ *
+ * Register the clocks described by the CGU with the common clock framework.
+ *
+ * Return: 0 on success or -errno if unsuccesful.
+ */
+int ingenic_cgu_register_clocks(struct ingenic_cgu *cgu);
+
+#endif /* __DRIVERS_CLK_INGENIC_CGU_H__ */