[PATCH v2 1/5] clk: Add clock driver for ASPEED BMC SoCs

[Joel Stanley <joel@jms.id.au>]

This adds the stub of a driver for the ASPEED SoCs. The clocks are
defined and the static registration is set up.

Signed-off-by: Joel Stanley <joel@jms.id.au>
---
 drivers/clk/Kconfig                      |  12 +++
 drivers/clk/Makefile                     |   1 +
 drivers/clk/clk-aspeed.c                 | 162 +++++++++++++++++++++++++++++++
 include/dt-bindings/clock/aspeed-clock.h |  43 ++++++++
 4 files changed, 218 insertions(+)
 create mode 100644 drivers/clk/clk-aspeed.c
 create mode 100644 include/dt-bindings/clock/aspeed-clock.h

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 1c4e1aa6767e..9abe063ef8d2 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -142,6 +142,18 @@ config COMMON_CLK_GEMINI
 	  This driver supports the SoC clocks on the Cortina Systems Gemini
 	  platform, also known as SL3516 or CS3516.
 
+config COMMON_CLK_ASPEED
+	bool "Clock driver for Aspeed BMC SoCs"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	default ARCH_ASPEED
+	select MFD_SYSCON
+	select RESET_CONTROLLER
+	---help---
+	  This driver supports the SoC clocks on the Aspeed BMC platforms.
+
+	  The G4 and G5 series, including the ast2400 and ast2500, are supported
+	  by this driver.
+
 config COMMON_CLK_S2MPS11
 	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
 	depends on MFD_SEC_CORE || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index c99f363826f0..575c68919d9b 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
 obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
 obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
 obj-$(CONFIG_COMMON_CLK_GEMINI)		+= clk-gemini.o
+obj-$(CONFIG_COMMON_CLK_ASPEED)		+= clk-aspeed.o
 obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o
 obj-$(CONFIG_CLK_HSDK)			+= clk-hsdk-pll.o
 obj-$(CONFIG_COMMON_CLK_MAX77686)	+= clk-max77686.o
diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
new file mode 100644
index 000000000000..824c54767009
--- /dev/null
+++ b/drivers/clk/clk-aspeed.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2017 IBM Corporation
+ *
+ * Joel Stanley <joel@jms.id.au>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "clk-aspeed: " fmt
+
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+#include <linux/mfd/syscon.h>
+
+#include <dt-bindings/clock/aspeed-clock.h>
+
+#define ASPEED_RESET_CTRL	0x04
+#define ASPEED_CLK_SELECTION	0x08
+#define ASPEED_CLK_STOP_CTRL	0x0c
+#define ASPEED_MPLL_PARAM	0x20
+#define ASPEED_HPLL_PARAM	0x24
+#define ASPEED_MISC_CTRL	0x2c
+#define ASPEED_STRAP		0x70
+
+/* Keeps track of all clocks */
+static struct clk_hw_onecell_data *aspeed_clk_data;
+
+static void __iomem *scu_base;
+
+/**
+ * struct aspeed_gate_data - Aspeed gated clocks
+ * @clock_idx: bit used to gate this clock in the clock register
+ * @reset_idx: bit used to reset this IP in the reset register. -1 if no
+ *             reset is required when enabling the clock
+ * @name: the clock name
+ * @parent_name: the name of the parent clock
+ * @flags: standard clock framework flags
+ */
+struct aspeed_gate_data {
+	u8		clock_idx;
+	s8		reset_idx;
+	const char	*name;
+	const char	*parent_name;
+	unsigned long	flags;
+};
+
+/**
+ * struct aspeed_clk_gate - Aspeed specific clk_gate structure
+ * @hw:		handle between common and hardware-specific interfaces
+ * @reg:	register controlling gate
+ * @clock_idx:	bit used to gate this clock in the clock register
+ * @reset_idx:	bit used to reset this IP in the reset register. -1 if no
+ *		reset is required when enabling the clock
+ * @flags:	hardware-specific flags
+ * @lock:	register lock
+ *
+ * Some of the clocks in the Aspeed SoC must be put in reset before enabling.
+ * This modified version of clk_gate allows an optional reset bit to be
+ * specified.
+ */
+struct aspeed_clk_gate {
+	struct clk_hw	hw;
+	struct regmap	*map;
+	u8		clock_idx;
+	s8		reset_idx;
+	u8		flags;
+	spinlock_t	*lock;
+};
+
+#define to_aspeed_clk_gate(_hw) container_of(_hw, struct aspeed_clk_gate, hw)
+
+/* TODO: ask Aspeed about the actual parent data */
+static const struct aspeed_gate_data aspeed_gates[] __initconst = {
+/*	 clk rst   name			parent		flags	*/
+	{  0, -1, "eclk-gate",		"eclk",		0 }, /* Video Engine */
+	{  1,  7, "gclk-gate",		NULL,		0 }, /* 2D engine */
+	{  2, -1, "mclk-gate",		"mpll",		CLK_IS_CRITICAL }, /* SDRAM */
+	{  3,  6, "vclk-gate",		NULL,		0 }, /* Video Capture */
+	{  4, 10, "bclk-gate",		"bclk",		0 }, /* PCIe/PCI */
+	{  5, -1, "dclk-gate",		NULL,		0 }, /* DAC */
+	{  6, -1, "refclk-gate",	"clkin",	CLK_IS_CRITICAL },
+	{  7,  3, "usb-port2-gate",	NULL,		0 }, /* USB2.0 Host port 2 */
+	{  8,  5, "lclk-gate",		NULL,		0 }, /* LPC */
+	{  9, 15, "usb-uhci-gate",	NULL,		0 }, /* USB1.1 (requires port 2 enabled) */
+	{ 10, 13, "d1clk-gate",		NULL,		0 }, /* GFX CRT */
+	/* 11: reserved */
+	/* 12: reserved */
+	{ 13, 4,  "yclk-gate",		NULL,		0 }, /* HAC */
+	{ 14, 14, "usb-port1-gate",	NULL,		0 }, /* USB2 hub/USB2 host port 1/USB1.1 dev */
+	{ 15, -1, "uart1clk-gate",	"uart",		0 }, /* UART1 */
+	{ 16, -1, "uart2clk-gate",	"uart",		0 }, /* UART2 */
+	{ 17, -1, "uart5clk-gate",	"uart",		0 }, /* UART5 */
+	/* 18: reserved */
+	{ 19, -1, "espiclk-gate",	NULL,		0 }, /* eSPI */
+	{ 20, 11, "mac1clk-gate",	"clkin",	0 }, /* MAC1 */
+	{ 21, 12, "mac2clk-gate",	"clkin",	0 }, /* MAC2 */
+	/* 22: reserved */
+	/* 23: reserved */
+	{ 24, -1, "rsaclk-gate",	NULL,		0 }, /* RSA */
+	{ 25, -1, "uart3clk-gate",	"uart",		0 }, /* UART3 */
+	{ 26, -1, "uart4clk-gate",	"uart",		0 }, /* UART4 */
+	{ 27, 16, "sdclk-gate",		NULL,		0 }, /* SDIO/SD */
+	{ 28, -1, "lhclk-gate",		"lhclk",	0 }, /* LPC master/LPC+ */
+	/* 29: reserved */
+	/* 30: reserved */
+	/* 31: reserved */
+};
+
+static void __init aspeed_cc_init(struct device_node *np)
+{
+	struct regmap *map;
+	u32 val;
+	int ret;
+	int i;
+
+	scu_base = of_iomap(np, 0);
+	if (IS_ERR(scu_base))
+		return;
+
+	aspeed_clk_data = kzalloc(sizeof(*aspeed_clk_data) +
+			sizeof(*aspeed_clk_data->hws) * ASPEED_NUM_CLKS,
+			GFP_KERNEL);
+	if (!aspeed_clk_data)
+		return;
+
+	/*
+	 * This way all clock fetched before the platform device probes,
+	 * except those we assign here for early use, will be deferred.
+	 */
+	for (i = 0; i < ASPEED_NUM_CLKS; i++)
+		aspeed_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
+
+	map = syscon_node_to_regmap(np);
+	if (IS_ERR(map)) {
+		pr_err("no syscon regmap\n");
+		return;
+	}
+	/*
+	 * We check that the regmap works on this very first access,
+	 * but as this is an MMIO-backed regmap, subsequent regmap
+	 * access is not going to fail and we skip error checks from
+	 * this point.
+	 */
+	ret = regmap_read(map, ASPEED_STRAP, &val);
+	if (ret) {
+		pr_err("failed to read strapping register\n");
+		return;
+	}
+
+	aspeed_clk_data->num = ASPEED_NUM_CLKS;
+	ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, aspeed_clk_data);
+	if (ret)
+		pr_err("failed to add DT provider: %d\n", ret);
+};
+CLK_OF_DECLARE_DRIVER(aspeed_cc_g5, "aspeed,ast2500-scu", aspeed_cc_init);
+CLK_OF_DECLARE_DRIVER(aspeed_cc_g4, "aspeed,ast2400-scu", aspeed_cc_init);
diff --git a/include/dt-bindings/clock/aspeed-clock.h b/include/dt-bindings/clock/aspeed-clock.h
new file mode 100644
index 000000000000..afe06b77562d
--- /dev/null
+++ b/include/dt-bindings/clock/aspeed-clock.h
@@ -0,0 +1,43 @@
+#ifndef DT_BINDINGS_ASPEED_CLOCK_H
+#define DT_BINDINGS_ASPEED_CLOCK_H
+
+#define ASPEED_NUM_CLKS	34
+
+#define ASPEED_CLK_HPLL			0
+#define ASPEED_CLK_AHB			1
+#define ASPEED_CLK_APB			2
+#define ASPEED_CLK_UART			3
+#define ASPEED_CLK_SDIO			4
+#define ASPEED_CLK_ECLK			5
+#define ASPEED_CLK_ECLK_MUX		6
+#define ASPEED_CLK_LHCLK		7
+#define ASPEED_CLK_MAC			8
+#define ASPEED_CLK_BCLK			9
+#define ASPEED_CLK_MPLL			10
+#define ASPEED_CLK_GATES		11
+#define ASPEED_CLK_GATE_ECLK		(0 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_GCLK		(1 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_MCLK		(2 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_VCLK		(3 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_BCLK		(4 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_DCLK		(5 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_REFCLK		(6 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_USBPORT2CLK	(7 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_LCLK		(8 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_USBUHCICLK	(9 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_D1CLK		(10 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_YCLK		(11 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_USBPORT1CLK	(12 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_UART1CLK	(13 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_UART2CLK	(14 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_UART5CLK	(15 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_ESPICLK		(16 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_MAC1CLK		(17 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_MAC2CLK		(18 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_RSACLK		(19 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_UART3CLK	(20 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_UART4CLK	(21 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_SDCLKCLK	(22 + ASPEED_CLK_GATES)
+#define ASPEED_CLK_GATE_LHCCLK		(23 + ASPEED_CLK_GATES)
+
+#endif
-- 
2.14.1