1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Purna Chandra Mandal,<purna.mandal@microchip.com>
4  * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
5  */
6 #include <dt-bindings/clock/microchip,pic32-clock.h>
7 #include <linux/clk.h>
8 #include <linux/clk-provider.h>
9 #include <linux/clkdev.h>
10 #include <linux/io.h>
11 #include <linux/module.h>
12 #include <linux/of_address.h>
13 #include <linux/of_platform.h>
14 #include <linux/platform_device.h>
15 #include <asm/traps.h>
16 
17 #include "clk-core.h"
18 
19 /* FRC Postscaler */
20 #define OSC_FRCDIV_MASK		0x07
21 #define OSC_FRCDIV_SHIFT	24
22 
23 /* SPLL fields */
24 #define PLL_ICLK_MASK		0x01
25 #define PLL_ICLK_SHIFT		7
26 
27 #define DECLARE_PERIPHERAL_CLOCK(__clk_name, __reg, __flags)	\
28 	{							\
29 		.ctrl_reg = (__reg),				\
30 		.init_data = {					\
31 			.name = (__clk_name),			\
32 			.parent_names = (const char *[]) {	\
33 				"sys_clk"			\
34 			},					\
35 			.num_parents = 1,			\
36 			.ops = &pic32_pbclk_ops,		\
37 			.flags = (__flags),			\
38 		},						\
39 	}
40 
41 #define DECLARE_REFO_CLOCK(__clkid, __reg)				\
42 	{								\
43 		.ctrl_reg = (__reg),					\
44 		.init_data = {						\
45 			.name = "refo" #__clkid "_clk",			\
46 			.parent_names = (const char *[]) {		\
47 				"sys_clk", "pb1_clk", "posc_clk",	\
48 				"frc_clk", "lprc_clk", "sosc_clk",	\
49 				"sys_pll", "refi" #__clkid "_clk",	\
50 				"bfrc_clk",				\
51 			},						\
52 			.num_parents = 9,				\
53 			.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE,\
54 			.ops = &pic32_roclk_ops,			\
55 		},							\
56 		.parent_map = (const u32[]) {				\
57 			0, 1, 2, 3, 4, 5, 7, 8, 9			\
58 		},							\
59 	}
60 
61 static const struct pic32_ref_osc_data ref_clks[] = {
62 	DECLARE_REFO_CLOCK(1, 0x80),
63 	DECLARE_REFO_CLOCK(2, 0xa0),
64 	DECLARE_REFO_CLOCK(3, 0xc0),
65 	DECLARE_REFO_CLOCK(4, 0xe0),
66 	DECLARE_REFO_CLOCK(5, 0x100),
67 };
68 
69 static const struct pic32_periph_clk_data periph_clocks[] = {
70 	DECLARE_PERIPHERAL_CLOCK("pb1_clk", 0x140, 0),
71 	DECLARE_PERIPHERAL_CLOCK("pb2_clk", 0x150, CLK_IGNORE_UNUSED),
72 	DECLARE_PERIPHERAL_CLOCK("pb3_clk", 0x160, 0),
73 	DECLARE_PERIPHERAL_CLOCK("pb4_clk", 0x170, 0),
74 	DECLARE_PERIPHERAL_CLOCK("pb5_clk", 0x180, 0),
75 	DECLARE_PERIPHERAL_CLOCK("pb6_clk", 0x190, 0),
76 	DECLARE_PERIPHERAL_CLOCK("cpu_clk", 0x1a0, CLK_IGNORE_UNUSED),
77 };
78 
79 static const struct pic32_sys_clk_data sys_mux_clk = {
80 	.slew_reg = 0x1c0,
81 	.slew_div = 2, /* step of div_4 -> div_2 -> no_div */
82 	.init_data = {
83 		.name = "sys_clk",
84 		.parent_names = (const char *[]) {
85 			"frcdiv_clk", "sys_pll", "posc_clk",
86 			"sosc_clk", "lprc_clk", "frcdiv_clk",
87 		},
88 		.num_parents = 6,
89 		.ops = &pic32_sclk_ops,
90 	},
91 	.parent_map = (const u32[]) {
92 		0, 1, 2, 4, 5, 7,
93 	},
94 };
95 
96 static const struct pic32_sys_pll_data sys_pll = {
97 	.ctrl_reg = 0x020,
98 	.status_reg = 0x1d0,
99 	.lock_mask = BIT(7),
100 	.init_data = {
101 		.name = "sys_pll",
102 		.parent_names = (const char *[]) {
103 			"spll_mux_clk"
104 		},
105 		.num_parents = 1,
106 		.ops = &pic32_spll_ops,
107 	},
108 };
109 
110 static const struct pic32_sec_osc_data sosc_clk = {
111 	.status_reg = 0x1d0,
112 	.enable_mask = BIT(1),
113 	.status_mask = BIT(4),
114 	.fixed_rate = 32768,
115 	.init_data = {
116 		.name = "sosc_clk",
117 		.parent_names = NULL,
118 		.ops = &pic32_sosc_ops,
119 	},
120 };
121 
122 static int pic32mzda_critical_clks[] = {
123 	PB2CLK, PB7CLK
124 };
125 
126 /* PIC32MZDA clock data */
127 struct pic32mzda_clk_data {
128 	struct clk *clks[MAXCLKS];
129 	struct pic32_clk_common core;
130 	struct clk_onecell_data onecell_data;
131 	struct notifier_block failsafe_notifier;
132 };
133 
134 static int pic32_fscm_nmi(struct notifier_block *nb,
135 			  unsigned long action, void *data)
136 {
137 	struct pic32mzda_clk_data *cd;
138 
139 	cd  = container_of(nb, struct pic32mzda_clk_data, failsafe_notifier);
140 
141 	/* SYSCLK is now running from BFRCCLK. Report clock failure. */
142 	if (readl(cd->core.iobase) & BIT(2))
143 		pr_alert("pic32-clk: FSCM detected clk failure.\n");
144 
145 	/* TODO: detect reason of failure and recover accordingly */
146 
147 	return NOTIFY_OK;
148 }
149 
150 static int pic32mzda_clk_probe(struct platform_device *pdev)
151 {
152 	const char *const pll_mux_parents[] = {"posc_clk", "frc_clk"};
153 	struct device_node *np = pdev->dev.of_node;
154 	struct pic32mzda_clk_data *cd;
155 	struct pic32_clk_common *core;
156 	struct clk *pll_mux_clk, *clk;
157 	struct clk **clks;
158 	int nr_clks, i, ret;
159 
160 	cd = devm_kzalloc(&pdev->dev, sizeof(*cd), GFP_KERNEL);
161 	if (!cd)
162 		return -ENOMEM;
163 
164 	core = &cd->core;
165 	core->iobase = of_io_request_and_map(np, 0, of_node_full_name(np));
166 	if (IS_ERR(core->iobase)) {
167 		dev_err(&pdev->dev, "pic32-clk: failed to map registers\n");
168 		return PTR_ERR(core->iobase);
169 	}
170 
171 	spin_lock_init(&core->reg_lock);
172 	core->dev = &pdev->dev;
173 	clks = &cd->clks[0];
174 
175 	/* register fixed rate clocks */
176 	clks[POSCCLK] = clk_register_fixed_rate(&pdev->dev, "posc_clk", NULL,
177 						0, 24000000);
178 	clks[FRCCLK] =  clk_register_fixed_rate(&pdev->dev, "frc_clk", NULL,
179 						0, 8000000);
180 	clks[BFRCCLK] = clk_register_fixed_rate(&pdev->dev, "bfrc_clk", NULL,
181 						0, 8000000);
182 	clks[LPRCCLK] = clk_register_fixed_rate(&pdev->dev, "lprc_clk", NULL,
183 						0, 32000);
184 	clks[UPLLCLK] = clk_register_fixed_rate(&pdev->dev, "usbphy_clk", NULL,
185 						0, 24000000);
186 	/* fixed rate (optional) clock */
187 	if (of_property_read_bool(np, "microchip,pic32mzda-sosc")) {
188 		pr_info("pic32-clk: dt requests SOSC.\n");
189 		clks[SOSCCLK] = pic32_sosc_clk_register(&sosc_clk, core);
190 	}
191 	/* divider clock */
192 	clks[FRCDIVCLK] = clk_register_divider(&pdev->dev, "frcdiv_clk",
193 					       "frc_clk", 0,
194 					       core->iobase,
195 					       OSC_FRCDIV_SHIFT,
196 					       OSC_FRCDIV_MASK,
197 					       CLK_DIVIDER_POWER_OF_TWO,
198 					       &core->reg_lock);
199 	/* PLL ICLK mux */
200 	pll_mux_clk = clk_register_mux(&pdev->dev, "spll_mux_clk",
201 				       pll_mux_parents, 2, 0,
202 				       core->iobase + 0x020,
203 				       PLL_ICLK_SHIFT, 1, 0, &core->reg_lock);
204 	if (IS_ERR(pll_mux_clk))
205 		pr_err("spll_mux_clk: clk register failed\n");
206 
207 	/* PLL */
208 	clks[PLLCLK] = pic32_spll_clk_register(&sys_pll, core);
209 	/* SYSTEM clock */
210 	clks[SCLK] = pic32_sys_clk_register(&sys_mux_clk, core);
211 	/* Peripheral bus clocks */
212 	for (nr_clks = PB1CLK, i = 0; nr_clks <= PB7CLK; i++, nr_clks++)
213 		clks[nr_clks] = pic32_periph_clk_register(&periph_clocks[i],
214 							  core);
215 	/* Reference oscillator clock */
216 	for (nr_clks = REF1CLK, i = 0; nr_clks <= REF5CLK; i++, nr_clks++)
217 		clks[nr_clks] = pic32_refo_clk_register(&ref_clks[i], core);
218 
219 	/* register clkdev */
220 	for (i = 0; i < MAXCLKS; i++) {
221 		if (IS_ERR(clks[i]))
222 			continue;
223 		clk_register_clkdev(clks[i], NULL, __clk_get_name(clks[i]));
224 	}
225 
226 	/* register clock provider */
227 	cd->onecell_data.clks = clks;
228 	cd->onecell_data.clk_num = MAXCLKS;
229 	ret = of_clk_add_provider(np, of_clk_src_onecell_get,
230 				  &cd->onecell_data);
231 	if (ret)
232 		return ret;
233 
234 	/* force enable critical clocks */
235 	for (i = 0; i < ARRAY_SIZE(pic32mzda_critical_clks); i++) {
236 		clk = clks[pic32mzda_critical_clks[i]];
237 		if (clk_prepare_enable(clk))
238 			dev_err(&pdev->dev, "clk_prepare_enable(%s) failed\n",
239 				__clk_get_name(clk));
240 	}
241 
242 	/* register NMI for failsafe clock monitor */
243 	cd->failsafe_notifier.notifier_call = pic32_fscm_nmi;
244 	return register_nmi_notifier(&cd->failsafe_notifier);
245 }
246 
247 static const struct of_device_id pic32mzda_clk_match_table[] = {
248 	{ .compatible = "microchip,pic32mzda-clk", },
249 	{ }
250 };
251 MODULE_DEVICE_TABLE(of, pic32mzda_clk_match_table);
252 
253 static struct platform_driver pic32mzda_clk_driver = {
254 	.probe		= pic32mzda_clk_probe,
255 	.driver		= {
256 		.name	= "clk-pic32mzda",
257 		.of_match_table = pic32mzda_clk_match_table,
258 	},
259 };
260 
261 static int __init microchip_pic32mzda_clk_init(void)
262 {
263 	return platform_driver_register(&pic32mzda_clk_driver);
264 }
265 core_initcall(microchip_pic32mzda_clk_init);
266 
267 MODULE_DESCRIPTION("Microchip PIC32MZDA Clock Driver");
268 MODULE_LICENSE("GPL v2");
269 MODULE_ALIAS("platform:clk-pic32mzda");
270