CLK: microchip: Add Microchip PIC32 clock driver.

This clock driver implements PIC32 specific clock-tree. clock-tree
entities can only be configured through device-tree file (OF).
Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-clk@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13247/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

drivers/clk/Kconfig

@@ -197,6 +197,9 @@ config COMMON_CLK_PXA
 	---help---
 	  Support for the Marvell PXA SoC.
 
+config COMMON_CLK_PIC32
+	def_bool COMMON_CLK && MACH_PIC32
+
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/mvebu/Kconfig"

drivers/clk/Makefile

@@ -58,6 +58,7 @@ obj-$(CONFIG_ARCH_MXC)			+= imx/
 obj-$(CONFIG_MACH_INGENIC)		+= ingenic/
 obj-$(CONFIG_COMMON_CLK_KEYSTONE)	+= keystone/
 obj-$(CONFIG_ARCH_MEDIATEK)		+= mediatek/
+obj-$(CONFIG_MACH_PIC32)		+= microchip/
 ifeq ($(CONFIG_COMMON_CLK), y)
 obj-$(CONFIG_ARCH_MMP)			+= mmp/
 endif

drivers/clk/microchip/Makefile

+obj-$(CONFIG_COMMON_CLK_PIC32) += clk-core.o
+obj-$(CONFIG_PIC32MZDA) += clk-pic32mzda.o

drivers/clk/microchip/clk-core.h

+/*
+ * Purna Chandra Mandal,<purna.mandal@microchip.com>
+ * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 __MICROCHIP_CLK_PIC32_H_
+#define __MICROCHIP_CLK_PIC32_H_
+
+#include <linux/clk-provider.h>
+
+/* PIC32 clock data */
+struct pic32_clk_common {
+	struct device *dev;
+	void __iomem *iobase;
+	spinlock_t reg_lock; /* clock lock */
+};
+
+/* System PLL clock */
+struct pic32_sys_pll_data {
+	struct clk_init_data init_data;
+	const u32 ctrl_reg;
+	const u32 status_reg;
+	const u32 lock_mask;
+};
+
+/* System clock */
+struct pic32_sys_clk_data {
+	struct clk_init_data init_data;
+	const u32 mux_reg;
+	const u32 slew_reg;
+	const u32 *parent_map;
+	const u32 slew_div;
+};
+
+/* Reference Oscillator clock */
+struct pic32_ref_osc_data {
+	struct clk_init_data init_data;
+	const u32 ctrl_reg;
+	const u32 *parent_map;
+};
+
+/* Peripheral Bus clock */
+struct pic32_periph_clk_data {
+	struct clk_init_data init_data;
+	const u32 ctrl_reg;
+};
+
+/* External Secondary Oscillator clock  */
+struct pic32_sec_osc_data {
+	struct clk_init_data init_data;
+	const u32 enable_reg;
+	const u32 status_reg;
+	const u32 enable_mask;
+	const u32 status_mask;
+	const unsigned long fixed_rate;
+};
+
+extern const struct clk_ops pic32_pbclk_ops;
+extern const struct clk_ops pic32_sclk_ops;
+extern const struct clk_ops pic32_sclk_no_div_ops;
+extern const struct clk_ops pic32_spll_ops;
+extern const struct clk_ops pic32_roclk_ops;
+extern const struct clk_ops pic32_sosc_ops;
+
+struct clk *pic32_periph_clk_register(const struct pic32_periph_clk_data *data,
+				      struct pic32_clk_common *core);
+struct clk *pic32_refo_clk_register(const struct pic32_ref_osc_data *data,
+				    struct pic32_clk_common *core);
+struct clk *pic32_sys_clk_register(const struct pic32_sys_clk_data *data,
+				   struct pic32_clk_common *core);
+struct clk *pic32_spll_clk_register(const struct pic32_sys_pll_data *data,
+				    struct pic32_clk_common *core);
+struct clk *pic32_sosc_clk_register(const struct pic32_sec_osc_data *data,
+				    struct pic32_clk_common *core);
+
+#endif /* __MICROCHIP_CLK_PIC32_H_*/

drivers/clk/microchip/clk-pic32mzda.c

+/*
+ * Purna Chandra Mandal,<purna.mandal@microchip.com>
+ * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+#include <dt-bindings/clock/microchip,pic32-clock.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <asm/traps.h>
+
+#include "clk-core.h"
+
+/* FRC Postscaler */
+#define OSC_FRCDIV_MASK		0x07
+#define OSC_FRCDIV_SHIFT	24
+
+/* SPLL fields */
+#define PLL_ICLK_MASK		0x01
+#define PLL_ICLK_SHIFT		7
+
+#define DECLARE_PERIPHERAL_CLOCK(__clk_name, __reg, __flags)	\
+	{							\
+		.ctrl_reg = (__reg),				\
+		.init_data = {					\
+			.name = (__clk_name),			\
+			.parent_names = (const char *[]) {	\
+				"sys_clk"			\
+			},					\
+			.num_parents = 1,			\
+			.ops = &pic32_pbclk_ops,		\
+			.flags = (__flags),			\
+		},						\
+	}
+
+#define DECLARE_REFO_CLOCK(__clkid, __reg)				\
+	{								\
+		.ctrl_reg = (__reg),					\
+		.init_data = {						\
+			.name = "refo" #__clkid "_clk",			\
+			.parent_names = (const char *[]) {		\
+				"sys_clk", "pb1_clk", "posc_clk",	\
+				"frc_clk", "lprc_clk", "sosc_clk",	\
+				"sys_pll", "refi" #__clkid "_clk",	\
+				"bfrc_clk",				\
+			},						\
+			.num_parents = 9,				\
+			.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE,\
+			.ops = &pic32_roclk_ops,			\
+		},							\
+		.parent_map = (const u32[]) {				\
+			0, 1, 2, 3, 4, 5, 7, 8, 9			\
+		},							\
+	}
+
+static const struct pic32_ref_osc_data ref_clks[] = {
+	DECLARE_REFO_CLOCK(1, 0x80),
+	DECLARE_REFO_CLOCK(2, 0xa0),
+	DECLARE_REFO_CLOCK(3, 0xc0),
+	DECLARE_REFO_CLOCK(4, 0xe0),
+	DECLARE_REFO_CLOCK(5, 0x100),
+};
+
+static const struct pic32_periph_clk_data periph_clocks[] = {
+	DECLARE_PERIPHERAL_CLOCK("pb1_clk", 0x140, 0),
+	DECLARE_PERIPHERAL_CLOCK("pb2_clk", 0x150, CLK_IGNORE_UNUSED),
+	DECLARE_PERIPHERAL_CLOCK("pb3_clk", 0x160, 0),
+	DECLARE_PERIPHERAL_CLOCK("pb4_clk", 0x170, 0),
+	DECLARE_PERIPHERAL_CLOCK("pb5_clk", 0x180, 0),
+	DECLARE_PERIPHERAL_CLOCK("pb6_clk", 0x190, 0),
+	DECLARE_PERIPHERAL_CLOCK("cpu_clk", 0x1a0, CLK_IGNORE_UNUSED),
+};
+
+static const struct pic32_sys_clk_data sys_mux_clk = {
+	.slew_reg = 0x1c0,
+	.slew_div = 2, /* step of div_4 -> div_2 -> no_div */
+	.init_data = {
+		.name = "sys_clk",
+		.parent_names = (const char *[]) {
+			"frcdiv_clk", "sys_pll", "posc_clk",
+			"sosc_clk", "lprc_clk", "frcdiv_clk",
+		},
+		.num_parents = 6,
+		.ops = &pic32_sclk_ops,
+	},
+	.parent_map = (const u32[]) {
+		0, 1, 2, 4, 5, 7,
+	},
+};
+
+static const struct pic32_sys_pll_data sys_pll = {
+	.ctrl_reg = 0x020,
+	.status_reg = 0x1d0,
+	.lock_mask = BIT(7),
+	.init_data = {
+		.name = "sys_pll",
+		.parent_names = (const char *[]) {
+			"spll_mux_clk"
+		},
+		.num_parents = 1,
+		.ops = &pic32_spll_ops,
+	},
+};
+
+static const struct pic32_sec_osc_data sosc_clk = {
+	.status_reg = 0x1d0,
+	.enable_mask = BIT(1),
+	.status_mask = BIT(4),
+	.init_data = {
+		.name = "sosc_clk",
+		.parent_names = NULL,
+		.ops = &pic32_sosc_ops,
+	},
+};
+
+static int pic32mzda_critical_clks[] = {
+	PB2CLK, PB7CLK
+};
+
+/* PIC32MZDA clock data */
+struct pic32mzda_clk_data {
+	struct clk *clks[MAXCLKS];
+	struct pic32_clk_common core;
+	struct clk_onecell_data onecell_data;
+	struct notifier_block failsafe_notifier;
+};
+
+static int pic32_fscm_nmi(struct notifier_block *nb,
+			  unsigned long action, void *data)
+{
+	struct pic32mzda_clk_data *cd;
+
+	cd  = container_of(nb, struct pic32mzda_clk_data, failsafe_notifier);
+
+	/* SYSCLK is now running from BFRCCLK. Report clock failure. */
+	if (readl(cd->core.iobase) & BIT(2))
+		pr_alert("pic32-clk: FSCM detected clk failure.\n");
+
+	/* TODO: detect reason of failure and recover accordingly */
+
+	return NOTIFY_OK;
+}
+
+static int pic32mzda_clk_probe(struct platform_device *pdev)
+{
+	const char *const pll_mux_parents[] = {"posc_clk", "frc_clk"};
+	struct device_node *np = pdev->dev.of_node;
+	struct pic32mzda_clk_data *cd;
+	struct pic32_clk_common *core;
+	struct clk *pll_mux_clk, *clk;
+	struct clk **clks;
+	int nr_clks, i, ret;
+
+	cd = devm_kzalloc(&pdev->dev, sizeof(*cd), GFP_KERNEL);
+	if (!cd)
+		return -ENOMEM;
+
+	core = &cd->core;
+	core->iobase = of_io_request_and_map(np, 0, of_node_full_name(np));
+	if (IS_ERR(core->iobase)) {
+		dev_err(&pdev->dev, "pic32-clk: failed to map registers\n");
+		return PTR_ERR(core->iobase);
+	}
+
+	spin_lock_init(&core->reg_lock);
+	core->dev = &pdev->dev;
+	clks = &cd->clks[0];
+
+	/* register fixed rate clocks */
+	clks[POSCCLK] = clk_register_fixed_rate(&pdev->dev, "posc_clk", NULL,
+						CLK_IS_ROOT, 24000000);
+	clks[FRCCLK] =  clk_register_fixed_rate(&pdev->dev, "frc_clk", NULL,
+						CLK_IS_ROOT, 8000000);
+	clks[BFRCCLK] = clk_register_fixed_rate(&pdev->dev, "bfrc_clk", NULL,
+						CLK_IS_ROOT, 8000000);
+	clks[LPRCCLK] = clk_register_fixed_rate(&pdev->dev, "lprc_clk", NULL,
+						CLK_IS_ROOT, 32000);
+	clks[UPLLCLK] = clk_register_fixed_rate(&pdev->dev, "usbphy_clk", NULL,
+						CLK_IS_ROOT, 24000000);
+	/* fixed rate (optional) clock */
+	if (of_find_property(np, "microchip,pic32mzda-sosc", NULL)) {
+		pr_info("pic32-clk: dt requests SOSC.\n");
+		clks[SOSCCLK] = pic32_sosc_clk_register(&sosc_clk, core);
+	}
+	/* divider clock */
+	clks[FRCDIVCLK] = clk_register_divider(&pdev->dev, "frcdiv_clk",
+					       "frc_clk", 0,
+					       core->iobase,
+					       OSC_FRCDIV_SHIFT,
+					       OSC_FRCDIV_MASK,
+					       CLK_DIVIDER_POWER_OF_TWO,
+					       &core->reg_lock);
+	/* PLL ICLK mux */
+	pll_mux_clk = clk_register_mux(&pdev->dev, "spll_mux_clk",
+				       pll_mux_parents, 2, 0,
+				       core->iobase + 0x020,
+				       PLL_ICLK_SHIFT, 1, 0, &core->reg_lock);
+	if (IS_ERR(pll_mux_clk))
+		pr_err("spll_mux_clk: clk register failed\n");
+
+	/* PLL */
+	clks[PLLCLK] = pic32_spll_clk_register(&sys_pll, core);
+	/* SYSTEM clock */
+	clks[SCLK] = pic32_sys_clk_register(&sys_mux_clk, core);
+	/* Peripheral bus clocks */
+	for (nr_clks = PB1CLK, i = 0; nr_clks <= PB7CLK; i++, nr_clks++)
+		clks[nr_clks] = pic32_periph_clk_register(&periph_clocks[i],
+							  core);
+	/* Reference oscillator clock */
+	for (nr_clks = REF1CLK, i = 0; nr_clks <= REF5CLK; i++, nr_clks++)
+		clks[nr_clks] = pic32_refo_clk_register(&ref_clks[i], core);
+
+	/* register clkdev */
+	for (i = 0; i < MAXCLKS; i++) {
+		if (IS_ERR(clks[i]))
+			continue;
+		clk_register_clkdev(clks[i], NULL, __clk_get_name(clks[i]));
+	}
+
+	/* register clock provider */
+	cd->onecell_data.clks = clks;
+	cd->onecell_data.clk_num = MAXCLKS;
+	ret = of_clk_add_provider(np, of_clk_src_onecell_get,
+				  &cd->onecell_data);
+	if (ret)
+		return ret;
+
+	/* force enable critical clocks */
+	for (i = 0; i < ARRAY_SIZE(pic32mzda_critical_clks); i++) {
+		clk = clks[pic32mzda_critical_clks[i]];
+		if (clk_prepare_enable(clk))
+			dev_err(&pdev->dev, "clk_prepare_enable(%s) failed\n",
+				__clk_get_name(clk));
+	}
+
+	/* register NMI for failsafe clock monitor */
+	cd->failsafe_notifier.notifier_call = pic32_fscm_nmi;
+	return register_nmi_notifier(&cd->failsafe_notifier);
+}
+
+static const struct of_device_id pic32mzda_clk_match_table[] = {
+	{ .compatible = "microchip,pic32mzda-clk", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pic32mzda_clk_match_table);
+
+static struct platform_driver pic32mzda_clk_driver = {
+	.probe		= pic32mzda_clk_probe,
+	.driver		= {
+		.name	= "clk-pic32mzda",
+		.of_match_table = pic32mzda_clk_match_table,
+	},
+};
+
+static int __init microchip_pic32mzda_clk_init(void)
+{
+	return platform_driver_register(&pic32mzda_clk_driver);
+}
+core_initcall(microchip_pic32mzda_clk_init);
+
+MODULE_DESCRIPTION("Microchip PIC32MZDA Clock Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:clk-pic32mzda");