1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2019 Baylibre, SAS.
3  * Author: Jerome Brunet <jbrunet@baylibre.com>
4  */
5 
6 #include <linux/bitfield.h>
7 #include <linux/clk.h>
8 #include <linux/clk-provider.h>
9 #include <linux/device.h>
10 #include <linux/io.h>
11 #include <linux/iopoll.h>
12 #include <linux/mdio-mux.h>
13 #include <linux/module.h>
14 #include <linux/phy.h>
15 #include <linux/platform_device.h>
16 
17 #define ETH_PLL_STS		0x40
18 #define ETH_PLL_CTL0		0x44
19 #define  PLL_CTL0_LOCK_DIG	BIT(30)
20 #define  PLL_CTL0_RST		BIT(29)
21 #define  PLL_CTL0_EN		BIT(28)
22 #define  PLL_CTL0_SEL		BIT(23)
23 #define  PLL_CTL0_N		GENMASK(14, 10)
24 #define  PLL_CTL0_M		GENMASK(8, 0)
25 #define  PLL_LOCK_TIMEOUT	1000000
26 #define  PLL_MUX_NUM_PARENT	2
27 #define ETH_PLL_CTL1		0x48
28 #define ETH_PLL_CTL2		0x4c
29 #define ETH_PLL_CTL3		0x50
30 #define ETH_PLL_CTL4		0x54
31 #define ETH_PLL_CTL5		0x58
32 #define ETH_PLL_CTL6		0x5c
33 #define ETH_PLL_CTL7		0x60
34 
35 #define ETH_PHY_CNTL0		0x80
36 #define   EPHY_G12A_ID		0x33010180
37 #define ETH_PHY_CNTL1		0x84
38 #define  PHY_CNTL1_ST_MODE	GENMASK(2, 0)
39 #define  PHY_CNTL1_ST_PHYADD	GENMASK(7, 3)
40 #define   EPHY_DFLT_ADD		8
41 #define  PHY_CNTL1_MII_MODE	GENMASK(15, 14)
42 #define   EPHY_MODE_RMII	0x1
43 #define  PHY_CNTL1_CLK_EN	BIT(16)
44 #define  PHY_CNTL1_CLKFREQ	BIT(17)
45 #define  PHY_CNTL1_PHY_ENB	BIT(18)
46 #define ETH_PHY_CNTL2		0x88
47 #define  PHY_CNTL2_USE_INTERNAL	BIT(5)
48 #define  PHY_CNTL2_SMI_SRC_MAC	BIT(6)
49 #define  PHY_CNTL2_RX_CLK_EPHY	BIT(9)
50 
51 #define MESON_G12A_MDIO_EXTERNAL_ID 0
52 #define MESON_G12A_MDIO_INTERNAL_ID 1
53 
54 struct g12a_mdio_mux {
55 	bool pll_is_enabled;
56 	void __iomem *regs;
57 	void *mux_handle;
58 	struct clk *pclk;
59 	struct clk *pll;
60 };
61 
62 struct g12a_ephy_pll {
63 	void __iomem *base;
64 	struct clk_hw hw;
65 };
66 
67 #define g12a_ephy_pll_to_dev(_hw)			\
68 	container_of(_hw, struct g12a_ephy_pll, hw)
69 
70 static unsigned long g12a_ephy_pll_recalc_rate(struct clk_hw *hw,
71 					       unsigned long parent_rate)
72 {
73 	struct g12a_ephy_pll *pll = g12a_ephy_pll_to_dev(hw);
74 	u32 val, m, n;
75 
76 	val = readl(pll->base + ETH_PLL_CTL0);
77 	m = FIELD_GET(PLL_CTL0_M, val);
78 	n = FIELD_GET(PLL_CTL0_N, val);
79 
80 	return parent_rate * m / n;
81 }
82 
83 static int g12a_ephy_pll_enable(struct clk_hw *hw)
84 {
85 	struct g12a_ephy_pll *pll = g12a_ephy_pll_to_dev(hw);
86 	u32 val = readl(pll->base + ETH_PLL_CTL0);
87 
88 	/* Apply both enable an reset */
89 	val |= PLL_CTL0_RST | PLL_CTL0_EN;
90 	writel(val, pll->base + ETH_PLL_CTL0);
91 
92 	/* Clear the reset to let PLL lock */
93 	val &= ~PLL_CTL0_RST;
94 	writel(val, pll->base + ETH_PLL_CTL0);
95 
96 	/* Poll on the digital lock instead of the usual analog lock
97 	 * This is done because bit 31 is unreliable on some SoC. Bit
98 	 * 31 may indicate that the PLL is not lock even though the clock
99 	 * is actually running
100 	 */
101 	return readl_poll_timeout(pll->base + ETH_PLL_CTL0, val,
102 				  val & PLL_CTL0_LOCK_DIG, 0, PLL_LOCK_TIMEOUT);
103 }
104 
105 static void g12a_ephy_pll_disable(struct clk_hw *hw)
106 {
107 	struct g12a_ephy_pll *pll = g12a_ephy_pll_to_dev(hw);
108 	u32 val;
109 
110 	val = readl(pll->base + ETH_PLL_CTL0);
111 	val &= ~PLL_CTL0_EN;
112 	val |= PLL_CTL0_RST;
113 	writel(val, pll->base + ETH_PLL_CTL0);
114 }
115 
116 static int g12a_ephy_pll_is_enabled(struct clk_hw *hw)
117 {
118 	struct g12a_ephy_pll *pll = g12a_ephy_pll_to_dev(hw);
119 	unsigned int val;
120 
121 	val = readl(pll->base + ETH_PLL_CTL0);
122 
123 	return (val & PLL_CTL0_LOCK_DIG) ? 1 : 0;
124 }
125 
126 static int g12a_ephy_pll_init(struct clk_hw *hw)
127 {
128 	struct g12a_ephy_pll *pll = g12a_ephy_pll_to_dev(hw);
129 
130 	/* Apply PLL HW settings */
131 	writel(0x29c0040a, pll->base + ETH_PLL_CTL0);
132 	writel(0x927e0000, pll->base + ETH_PLL_CTL1);
133 	writel(0xac5f49e5, pll->base + ETH_PLL_CTL2);
134 	writel(0x00000000, pll->base + ETH_PLL_CTL3);
135 	writel(0x00000000, pll->base + ETH_PLL_CTL4);
136 	writel(0x20200000, pll->base + ETH_PLL_CTL5);
137 	writel(0x0000c002, pll->base + ETH_PLL_CTL6);
138 	writel(0x00000023, pll->base + ETH_PLL_CTL7);
139 
140 	return 0;
141 }
142 
143 static const struct clk_ops g12a_ephy_pll_ops = {
144 	.recalc_rate	= g12a_ephy_pll_recalc_rate,
145 	.is_enabled	= g12a_ephy_pll_is_enabled,
146 	.enable		= g12a_ephy_pll_enable,
147 	.disable	= g12a_ephy_pll_disable,
148 	.init		= g12a_ephy_pll_init,
149 };
150 
151 static int g12a_enable_internal_mdio(struct g12a_mdio_mux *priv)
152 {
153 	int ret;
154 
155 	/* Enable the phy clock */
156 	if (!priv->pll_is_enabled) {
157 		ret = clk_prepare_enable(priv->pll);
158 		if (ret)
159 			return ret;
160 	}
161 
162 	priv->pll_is_enabled = true;
163 
164 	/* Initialize ephy control */
165 	writel(EPHY_G12A_ID, priv->regs + ETH_PHY_CNTL0);
166 	writel(FIELD_PREP(PHY_CNTL1_ST_MODE, 3) |
167 	       FIELD_PREP(PHY_CNTL1_ST_PHYADD, EPHY_DFLT_ADD) |
168 	       FIELD_PREP(PHY_CNTL1_MII_MODE, EPHY_MODE_RMII) |
169 	       PHY_CNTL1_CLK_EN |
170 	       PHY_CNTL1_CLKFREQ |
171 	       PHY_CNTL1_PHY_ENB,
172 	       priv->regs + ETH_PHY_CNTL1);
173 	writel(PHY_CNTL2_USE_INTERNAL |
174 	       PHY_CNTL2_SMI_SRC_MAC |
175 	       PHY_CNTL2_RX_CLK_EPHY,
176 	       priv->regs + ETH_PHY_CNTL2);
177 
178 	return 0;
179 }
180 
181 static int g12a_enable_external_mdio(struct g12a_mdio_mux *priv)
182 {
183 	/* Reset the mdio bus mux */
184 	writel_relaxed(0x0, priv->regs + ETH_PHY_CNTL2);
185 
186 	/* Disable the phy clock if enabled */
187 	if (priv->pll_is_enabled) {
188 		clk_disable_unprepare(priv->pll);
189 		priv->pll_is_enabled = false;
190 	}
191 
192 	return 0;
193 }
194 
195 static int g12a_mdio_switch_fn(int current_child, int desired_child,
196 			       void *data)
197 {
198 	struct g12a_mdio_mux *priv = dev_get_drvdata(data);
199 
200 	if (current_child == desired_child)
201 		return 0;
202 
203 	switch (desired_child) {
204 	case MESON_G12A_MDIO_EXTERNAL_ID:
205 		return g12a_enable_external_mdio(priv);
206 	case MESON_G12A_MDIO_INTERNAL_ID:
207 		return g12a_enable_internal_mdio(priv);
208 	default:
209 		return -EINVAL;
210 	}
211 }
212 
213 static const struct of_device_id g12a_mdio_mux_match[] = {
214 	{ .compatible = "amlogic,g12a-mdio-mux", },
215 	{},
216 };
217 MODULE_DEVICE_TABLE(of, g12a_mdio_mux_match);
218 
219 static int g12a_ephy_glue_clk_register(struct device *dev)
220 {
221 	struct g12a_mdio_mux *priv = dev_get_drvdata(dev);
222 	const char *parent_names[PLL_MUX_NUM_PARENT];
223 	struct clk_init_data init;
224 	struct g12a_ephy_pll *pll;
225 	struct clk_mux *mux;
226 	struct clk *clk;
227 	char *name;
228 	int i;
229 
230 	/* get the mux parents */
231 	for (i = 0; i < PLL_MUX_NUM_PARENT; i++) {
232 		char in_name[8];
233 
234 		snprintf(in_name, sizeof(in_name), "clkin%d", i);
235 		clk = devm_clk_get(dev, in_name);
236 		if (IS_ERR(clk)) {
237 			if (PTR_ERR(clk) != -EPROBE_DEFER)
238 				dev_err(dev, "Missing clock %s\n", in_name);
239 			return PTR_ERR(clk);
240 		}
241 
242 		parent_names[i] = __clk_get_name(clk);
243 	}
244 
245 	/* create the input mux */
246 	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
247 	if (!mux)
248 		return -ENOMEM;
249 
250 	name = kasprintf(GFP_KERNEL, "%s#mux", dev_name(dev));
251 	if (!name)
252 		return -ENOMEM;
253 
254 	init.name = name;
255 	init.ops = &clk_mux_ro_ops;
256 	init.flags = 0;
257 	init.parent_names = parent_names;
258 	init.num_parents = PLL_MUX_NUM_PARENT;
259 
260 	mux->reg = priv->regs + ETH_PLL_CTL0;
261 	mux->shift = __ffs(PLL_CTL0_SEL);
262 	mux->mask = PLL_CTL0_SEL >> mux->shift;
263 	mux->hw.init = &init;
264 
265 	clk = devm_clk_register(dev, &mux->hw);
266 	kfree(name);
267 	if (IS_ERR(clk)) {
268 		dev_err(dev, "failed to register input mux\n");
269 		return PTR_ERR(clk);
270 	}
271 
272 	/* create the pll */
273 	pll = devm_kzalloc(dev, sizeof(*pll), GFP_KERNEL);
274 	if (!pll)
275 		return -ENOMEM;
276 
277 	name = kasprintf(GFP_KERNEL, "%s#pll", dev_name(dev));
278 	if (!name)
279 		return -ENOMEM;
280 
281 	init.name = name;
282 	init.ops = &g12a_ephy_pll_ops;
283 	init.flags = 0;
284 	parent_names[0] = __clk_get_name(clk);
285 	init.parent_names = parent_names;
286 	init.num_parents = 1;
287 
288 	pll->base = priv->regs;
289 	pll->hw.init = &init;
290 
291 	clk = devm_clk_register(dev, &pll->hw);
292 	kfree(name);
293 	if (IS_ERR(clk)) {
294 		dev_err(dev, "failed to register input mux\n");
295 		return PTR_ERR(clk);
296 	}
297 
298 	priv->pll = clk;
299 
300 	return 0;
301 }
302 
303 static int g12a_mdio_mux_probe(struct platform_device *pdev)
304 {
305 	struct device *dev = &pdev->dev;
306 	struct g12a_mdio_mux *priv;
307 	int ret;
308 
309 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
310 	if (!priv)
311 		return -ENOMEM;
312 
313 	platform_set_drvdata(pdev, priv);
314 
315 	priv->regs = devm_platform_ioremap_resource(pdev, 0);
316 	if (IS_ERR(priv->regs))
317 		return PTR_ERR(priv->regs);
318 
319 	priv->pclk = devm_clk_get(dev, "pclk");
320 	if (IS_ERR(priv->pclk)) {
321 		ret = PTR_ERR(priv->pclk);
322 		if (ret != -EPROBE_DEFER)
323 			dev_err(dev, "failed to get peripheral clock\n");
324 		return ret;
325 	}
326 
327 	/* Make sure the device registers are clocked */
328 	ret = clk_prepare_enable(priv->pclk);
329 	if (ret) {
330 		dev_err(dev, "failed to enable peripheral clock");
331 		return ret;
332 	}
333 
334 	/* Register PLL in CCF */
335 	ret = g12a_ephy_glue_clk_register(dev);
336 	if (ret)
337 		goto err;
338 
339 	ret = mdio_mux_init(dev, dev->of_node, g12a_mdio_switch_fn,
340 			    &priv->mux_handle, dev, NULL);
341 	if (ret) {
342 		if (ret != -EPROBE_DEFER)
343 			dev_err(dev, "mdio multiplexer init failed: %d", ret);
344 		goto err;
345 	}
346 
347 	return 0;
348 
349 err:
350 	clk_disable_unprepare(priv->pclk);
351 	return ret;
352 }
353 
354 static int g12a_mdio_mux_remove(struct platform_device *pdev)
355 {
356 	struct g12a_mdio_mux *priv = platform_get_drvdata(pdev);
357 
358 	mdio_mux_uninit(priv->mux_handle);
359 
360 	if (priv->pll_is_enabled)
361 		clk_disable_unprepare(priv->pll);
362 
363 	clk_disable_unprepare(priv->pclk);
364 
365 	return 0;
366 }
367 
368 static struct platform_driver g12a_mdio_mux_driver = {
369 	.probe		= g12a_mdio_mux_probe,
370 	.remove		= g12a_mdio_mux_remove,
371 	.driver		= {
372 		.name	= "g12a-mdio_mux",
373 		.of_match_table = g12a_mdio_mux_match,
374 	},
375 };
376 module_platform_driver(g12a_mdio_mux_driver);
377 
378 MODULE_DESCRIPTION("Amlogic G12a MDIO multiplexer driver");
379 MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
380 MODULE_LICENSE("GPL v2");
381