xref: /openbmc/linux/drivers/clk/clk-hsdk-pll.c (revision ae213c44) 
1 /*
2  * Synopsys HSDK SDP Generic PLL clock driver
3  *
4  * Copyright (C) 2017 Synopsys
5  *
6  * This file is licensed under the terms of the GNU General Public
7  * License version 2. This program is licensed "as is" without any
8  * warranty of any kind, whether express or implied.
9  */
10 
11 #include <linux/clk-provider.h>
12 #include <linux/delay.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/io.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/of_device.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
21 
22 #define CGU_PLL_CTRL	0x000 /* ARC PLL control register */
23 #define CGU_PLL_STATUS	0x004 /* ARC PLL status register */
24 #define CGU_PLL_FMEAS	0x008 /* ARC PLL frequency measurement register */
25 #define CGU_PLL_MON	0x00C /* ARC PLL monitor register */
26 
27 #define CGU_PLL_CTRL_ODIV_SHIFT		2
28 #define CGU_PLL_CTRL_IDIV_SHIFT		4
29 #define CGU_PLL_CTRL_FBDIV_SHIFT	9
30 #define CGU_PLL_CTRL_BAND_SHIFT		20
31 
32 #define CGU_PLL_CTRL_ODIV_MASK		GENMASK(3, CGU_PLL_CTRL_ODIV_SHIFT)
33 #define CGU_PLL_CTRL_IDIV_MASK		GENMASK(8, CGU_PLL_CTRL_IDIV_SHIFT)
34 #define CGU_PLL_CTRL_FBDIV_MASK		GENMASK(15, CGU_PLL_CTRL_FBDIV_SHIFT)
35 
36 #define CGU_PLL_CTRL_PD			BIT(0)
37 #define CGU_PLL_CTRL_BYPASS		BIT(1)
38 
39 #define CGU_PLL_STATUS_LOCK		BIT(0)
40 #define CGU_PLL_STATUS_ERR		BIT(1)
41 
42 #define HSDK_PLL_MAX_LOCK_TIME		100 /* 100 us */
43 
44 #define CGU_PLL_SOURCE_MAX		1
45 
46 #define CORE_IF_CLK_THRESHOLD_HZ	500000000
47 #define CREG_CORE_IF_CLK_DIV_1		0x0
48 #define CREG_CORE_IF_CLK_DIV_2		0x1
49 
50 struct hsdk_pll_cfg {
51 	u32 rate;
52 	u32 idiv;
53 	u32 fbdiv;
54 	u32 odiv;
55 	u32 band;
56 };
57 
58 static const struct hsdk_pll_cfg asdt_pll_cfg[] = {
59 	{ 100000000,  0, 11, 3, 0 },
60 	{ 133000000,  0, 15, 3, 0 },
61 	{ 200000000,  1, 47, 3, 0 },
62 	{ 233000000,  1, 27, 2, 0 },
63 	{ 300000000,  1, 35, 2, 0 },
64 	{ 333000000,  1, 39, 2, 0 },
65 	{ 400000000,  1, 47, 2, 0 },
66 	{ 500000000,  0, 14, 1, 0 },
67 	{ 600000000,  0, 17, 1, 0 },
68 	{ 700000000,  0, 20, 1, 0 },
69 	{ 800000000,  0, 23, 1, 0 },
70 	{ 900000000,  1, 26, 0, 0 },
71 	{ 1000000000, 1, 29, 0, 0 },
72 	{ 1100000000, 1, 32, 0, 0 },
73 	{ 1200000000, 1, 35, 0, 0 },
74 	{ 1300000000, 1, 38, 0, 0 },
75 	{ 1400000000, 1, 41, 0, 0 },
76 	{ 1500000000, 1, 44, 0, 0 },
77 	{ 1600000000, 1, 47, 0, 0 },
78 	{}
79 };
80 
81 static const struct hsdk_pll_cfg hdmi_pll_cfg[] = {
82 	{ 297000000,  0, 21, 2, 0 },
83 	{ 540000000,  0, 19, 1, 0 },
84 	{ 594000000,  0, 21, 1, 0 },
85 	{}
86 };
87 
88 struct hsdk_pll_clk {
89 	struct clk_hw hw;
90 	void __iomem *regs;
91 	void __iomem *spec_regs;
92 	const struct hsdk_pll_devdata *pll_devdata;
93 	struct device *dev;
94 };
95 
96 struct hsdk_pll_devdata {
97 	const struct hsdk_pll_cfg *pll_cfg;
98 	int (*update_rate)(struct hsdk_pll_clk *clk, unsigned long rate,
99 			   const struct hsdk_pll_cfg *cfg);
100 };
101 
102 static int hsdk_pll_core_update_rate(struct hsdk_pll_clk *, unsigned long,
103 				     const struct hsdk_pll_cfg *);
104 static int hsdk_pll_comm_update_rate(struct hsdk_pll_clk *, unsigned long,
105 				     const struct hsdk_pll_cfg *);
106 
107 static const struct hsdk_pll_devdata core_pll_devdata = {
108 	.pll_cfg = asdt_pll_cfg,
109 	.update_rate = hsdk_pll_core_update_rate,
110 };
111 
112 static const struct hsdk_pll_devdata sdt_pll_devdata = {
113 	.pll_cfg = asdt_pll_cfg,
114 	.update_rate = hsdk_pll_comm_update_rate,
115 };
116 
117 static const struct hsdk_pll_devdata hdmi_pll_devdata = {
118 	.pll_cfg = hdmi_pll_cfg,
119 	.update_rate = hsdk_pll_comm_update_rate,
120 };
121 
122 static inline void hsdk_pll_write(struct hsdk_pll_clk *clk, u32 reg, u32 val)
123 {
124 	iowrite32(val, clk->regs + reg);
125 }
126 
127 static inline u32 hsdk_pll_read(struct hsdk_pll_clk *clk, u32 reg)
128 {
129 	return ioread32(clk->regs + reg);
130 }
131 
132 static inline void hsdk_pll_set_cfg(struct hsdk_pll_clk *clk,
133 				    const struct hsdk_pll_cfg *cfg)
134 {
135 	u32 val = 0;
136 
137 	/* Powerdown and Bypass bits should be cleared */
138 	val |= cfg->idiv << CGU_PLL_CTRL_IDIV_SHIFT;
139 	val |= cfg->fbdiv << CGU_PLL_CTRL_FBDIV_SHIFT;
140 	val |= cfg->odiv << CGU_PLL_CTRL_ODIV_SHIFT;
141 	val |= cfg->band << CGU_PLL_CTRL_BAND_SHIFT;
142 
143 	dev_dbg(clk->dev, "write configuration: %#x\n", val);
144 
145 	hsdk_pll_write(clk, CGU_PLL_CTRL, val);
146 }
147 
148 static inline bool hsdk_pll_is_locked(struct hsdk_pll_clk *clk)
149 {
150 	return !!(hsdk_pll_read(clk, CGU_PLL_STATUS) & CGU_PLL_STATUS_LOCK);
151 }
152 
153 static inline bool hsdk_pll_is_err(struct hsdk_pll_clk *clk)
154 {
155 	return !!(hsdk_pll_read(clk, CGU_PLL_STATUS) & CGU_PLL_STATUS_ERR);
156 }
157 
158 static inline struct hsdk_pll_clk *to_hsdk_pll_clk(struct clk_hw *hw)
159 {
160 	return container_of(hw, struct hsdk_pll_clk, hw);
161 }
162 
163 static unsigned long hsdk_pll_recalc_rate(struct clk_hw *hw,
164 					  unsigned long parent_rate)
165 {
166 	u32 val;
167 	u64 rate;
168 	u32 idiv, fbdiv, odiv;
169 	struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
170 
171 	val = hsdk_pll_read(clk, CGU_PLL_CTRL);
172 
173 	dev_dbg(clk->dev, "current configuration: %#x\n", val);
174 
175 	/* Check if PLL is disabled */
176 	if (val & CGU_PLL_CTRL_PD)
177 		return 0;
178 
179 	/* Check if PLL is bypassed */
180 	if (val & CGU_PLL_CTRL_BYPASS)
181 		return parent_rate;
182 
183 	/* input divider = reg.idiv + 1 */
184 	idiv = 1 + ((val & CGU_PLL_CTRL_IDIV_MASK) >> CGU_PLL_CTRL_IDIV_SHIFT);
185 	/* fb divider = 2*(reg.fbdiv + 1) */
186 	fbdiv = 2 * (1 + ((val & CGU_PLL_CTRL_FBDIV_MASK) >> CGU_PLL_CTRL_FBDIV_SHIFT));
187 	/* output divider = 2^(reg.odiv) */
188 	odiv = 1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> CGU_PLL_CTRL_ODIV_SHIFT);
189 
190 	rate = (u64)parent_rate * fbdiv;
191 	do_div(rate, idiv * odiv);
192 
193 	return rate;
194 }
195 
196 static long hsdk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
197 				unsigned long *prate)
198 {
199 	int i;
200 	unsigned long best_rate;
201 	struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
202 	const struct hsdk_pll_cfg *pll_cfg = clk->pll_devdata->pll_cfg;
203 
204 	if (pll_cfg[0].rate == 0)
205 		return -EINVAL;
206 
207 	best_rate = pll_cfg[0].rate;
208 
209 	for (i = 1; pll_cfg[i].rate != 0; i++) {
210 		if (abs(rate - pll_cfg[i].rate) < abs(rate - best_rate))
211 			best_rate = pll_cfg[i].rate;
212 	}
213 
214 	dev_dbg(clk->dev, "chosen best rate: %lu\n", best_rate);
215 
216 	return best_rate;
217 }
218 
219 static int hsdk_pll_comm_update_rate(struct hsdk_pll_clk *clk,
220 				     unsigned long rate,
221 				     const struct hsdk_pll_cfg *cfg)
222 {
223 	hsdk_pll_set_cfg(clk, cfg);
224 
225 	/*
226 	 * Wait until CGU relocks and check error status.
227 	 * If after timeout CGU is unlocked yet return error.
228 	 */
229 	udelay(HSDK_PLL_MAX_LOCK_TIME);
230 	if (!hsdk_pll_is_locked(clk))
231 		return -ETIMEDOUT;
232 
233 	if (hsdk_pll_is_err(clk))
234 		return -EINVAL;
235 
236 	return 0;
237 }
238 
239 static int hsdk_pll_core_update_rate(struct hsdk_pll_clk *clk,
240 				     unsigned long rate,
241 				     const struct hsdk_pll_cfg *cfg)
242 {
243 	/*
244 	 * When core clock exceeds 500MHz, the divider for the interface
245 	 * clock must be programmed to div-by-2.
246 	 */
247 	if (rate > CORE_IF_CLK_THRESHOLD_HZ)
248 		iowrite32(CREG_CORE_IF_CLK_DIV_2, clk->spec_regs);
249 
250 	hsdk_pll_set_cfg(clk, cfg);
251 
252 	/*
253 	 * Wait until CGU relocks and check error status.
254 	 * If after timeout CGU is unlocked yet return error.
255 	 */
256 	udelay(HSDK_PLL_MAX_LOCK_TIME);
257 	if (!hsdk_pll_is_locked(clk))
258 		return -ETIMEDOUT;
259 
260 	if (hsdk_pll_is_err(clk))
261 		return -EINVAL;
262 
263 	/*
264 	 * Program divider to div-by-1 if we succesfuly set core clock below
265 	 * 500MHz threshold.
266 	 */
267 	if (rate <= CORE_IF_CLK_THRESHOLD_HZ)
268 		iowrite32(CREG_CORE_IF_CLK_DIV_1, clk->spec_regs);
269 
270 	return 0;
271 }
272 
273 static int hsdk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
274 			     unsigned long parent_rate)
275 {
276 	int i;
277 	struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
278 	const struct hsdk_pll_cfg *pll_cfg = clk->pll_devdata->pll_cfg;
279 
280 	for (i = 0; pll_cfg[i].rate != 0; i++) {
281 		if (pll_cfg[i].rate == rate) {
282 			return clk->pll_devdata->update_rate(clk, rate,
283 							     &pll_cfg[i]);
284 		}
285 	}
286 
287 	dev_err(clk->dev, "invalid rate=%ld, parent_rate=%ld\n", rate,
288 			parent_rate);
289 
290 	return -EINVAL;
291 }
292 
293 static const struct clk_ops hsdk_pll_ops = {
294 	.recalc_rate = hsdk_pll_recalc_rate,
295 	.round_rate = hsdk_pll_round_rate,
296 	.set_rate = hsdk_pll_set_rate,
297 };
298 
299 static int hsdk_pll_clk_probe(struct platform_device *pdev)
300 {
301 	int ret;
302 	struct resource *mem;
303 	const char *parent_name;
304 	unsigned int num_parents;
305 	struct hsdk_pll_clk *pll_clk;
306 	struct clk_init_data init = { };
307 	struct device *dev = &pdev->dev;
308 
309 	pll_clk = devm_kzalloc(dev, sizeof(*pll_clk), GFP_KERNEL);
310 	if (!pll_clk)
311 		return -ENOMEM;
312 
313 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
314 	pll_clk->regs = devm_ioremap_resource(dev, mem);
315 	if (IS_ERR(pll_clk->regs))
316 		return PTR_ERR(pll_clk->regs);
317 
318 	init.name = dev->of_node->name;
319 	init.ops = &hsdk_pll_ops;
320 	parent_name = of_clk_get_parent_name(dev->of_node, 0);
321 	init.parent_names = &parent_name;
322 	num_parents = of_clk_get_parent_count(dev->of_node);
323 	if (num_parents == 0 || num_parents > CGU_PLL_SOURCE_MAX) {
324 		dev_err(dev, "wrong clock parents number: %u\n", num_parents);
325 		return -EINVAL;
326 	}
327 	init.num_parents = num_parents;
328 
329 	pll_clk->hw.init = &init;
330 	pll_clk->dev = dev;
331 	pll_clk->pll_devdata = of_device_get_match_data(dev);
332 
333 	if (!pll_clk->pll_devdata) {
334 		dev_err(dev, "No OF match data provided\n");
335 		return -EINVAL;
336 	}
337 
338 	ret = devm_clk_hw_register(dev, &pll_clk->hw);
339 	if (ret) {
340 		dev_err(dev, "failed to register %s clock\n", init.name);
341 		return ret;
342 	}
343 
344 	return of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
345 			&pll_clk->hw);
346 }
347 
348 static int hsdk_pll_clk_remove(struct platform_device *pdev)
349 {
350 	of_clk_del_provider(pdev->dev.of_node);
351 	return 0;
352 }
353 
354 static void __init of_hsdk_pll_clk_setup(struct device_node *node)
355 {
356 	int ret;
357 	const char *parent_name;
358 	unsigned int num_parents;
359 	struct hsdk_pll_clk *pll_clk;
360 	struct clk_init_data init = { };
361 
362 	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
363 	if (!pll_clk)
364 		return;
365 
366 	pll_clk->regs = of_iomap(node, 0);
367 	if (!pll_clk->regs) {
368 		pr_err("failed to map pll registers\n");
369 		goto err_free_pll_clk;
370 	}
371 
372 	pll_clk->spec_regs = of_iomap(node, 1);
373 	if (!pll_clk->spec_regs) {
374 		pr_err("failed to map pll registers\n");
375 		goto err_unmap_comm_regs;
376 	}
377 
378 	init.name = node->name;
379 	init.ops = &hsdk_pll_ops;
380 	parent_name = of_clk_get_parent_name(node, 0);
381 	init.parent_names = &parent_name;
382 	num_parents = of_clk_get_parent_count(node);
383 	if (num_parents > CGU_PLL_SOURCE_MAX) {
384 		pr_err("too much clock parents: %u\n", num_parents);
385 		goto err_unmap_spec_regs;
386 	}
387 	init.num_parents = num_parents;
388 
389 	pll_clk->hw.init = &init;
390 	pll_clk->pll_devdata = &core_pll_devdata;
391 
392 	ret = clk_hw_register(NULL, &pll_clk->hw);
393 	if (ret) {
394 		pr_err("failed to register %pOFn clock\n", node);
395 		goto err_unmap_spec_regs;
396 	}
397 
398 	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &pll_clk->hw);
399 	if (ret) {
400 		pr_err("failed to add hw provider for %pOFn clock\n", node);
401 		goto err_unmap_spec_regs;
402 	}
403 
404 	return;
405 
406 err_unmap_spec_regs:
407 	iounmap(pll_clk->spec_regs);
408 err_unmap_comm_regs:
409 	iounmap(pll_clk->regs);
410 err_free_pll_clk:
411 	kfree(pll_clk);
412 }
413 
414 /* Core PLL needed early for ARC cpus timers */
415 CLK_OF_DECLARE(hsdk_pll_clock, "snps,hsdk-core-pll-clock",
416 of_hsdk_pll_clk_setup);
417 
418 static const struct of_device_id hsdk_pll_clk_id[] = {
419 	{ .compatible = "snps,hsdk-gp-pll-clock", .data = &sdt_pll_devdata},
420 	{ .compatible = "snps,hsdk-hdmi-pll-clock", .data = &hdmi_pll_devdata},
421 	{ }
422 };
423 
424 static struct platform_driver hsdk_pll_clk_driver = {
425 	.driver = {
426 		.name = "hsdk-gp-pll-clock",
427 		.of_match_table = hsdk_pll_clk_id,
428 	},
429 	.probe = hsdk_pll_clk_probe,
430 	.remove = hsdk_pll_clk_remove,
431 };
432 builtin_platform_driver(hsdk_pll_clk_driver);
433