1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
2 /*
3  * Driver for the MDIO interface of Microsemi network switches.
4  *
5  * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
6  * Copyright (c) 2017 Microsemi Corporation
7  */
8 
9 #include <linux/bitops.h>
10 #include <linux/clk.h>
11 #include <linux/io.h>
12 #include <linux/iopoll.h>
13 #include <linux/kernel.h>
14 #include <linux/mdio/mdio-mscc-miim.h>
15 #include <linux/mfd/ocelot.h>
16 #include <linux/module.h>
17 #include <linux/of_mdio.h>
18 #include <linux/phy.h>
19 #include <linux/platform_device.h>
20 #include <linux/property.h>
21 #include <linux/regmap.h>
22 
23 #define MSCC_MIIM_REG_STATUS		0x0
24 #define		MSCC_MIIM_STATUS_STAT_PENDING	BIT(2)
25 #define		MSCC_MIIM_STATUS_STAT_BUSY	BIT(3)
26 #define MSCC_MIIM_REG_CMD		0x8
27 #define		MSCC_MIIM_CMD_OPR_WRITE		BIT(1)
28 #define		MSCC_MIIM_CMD_OPR_READ		BIT(2)
29 #define		MSCC_MIIM_CMD_WRDATA_SHIFT	4
30 #define		MSCC_MIIM_CMD_REGAD_SHIFT	20
31 #define		MSCC_MIIM_CMD_PHYAD_SHIFT	25
32 #define		MSCC_MIIM_CMD_VLD		BIT(31)
33 #define MSCC_MIIM_REG_DATA		0xC
34 #define		MSCC_MIIM_DATA_ERROR		(BIT(16) | BIT(17))
35 #define MSCC_MIIM_REG_CFG		0x10
36 #define		MSCC_MIIM_CFG_PRESCALE_MASK	GENMASK(7, 0)
37 
38 #define MSCC_PHY_REG_PHY_CFG	0x0
39 #define		PHY_CFG_PHY_ENA		(BIT(0) | BIT(1) | BIT(2) | BIT(3))
40 #define		PHY_CFG_PHY_COMMON_RESET BIT(4)
41 #define		PHY_CFG_PHY_RESET	(BIT(5) | BIT(6) | BIT(7) | BIT(8))
42 #define MSCC_PHY_REG_PHY_STATUS	0x4
43 
44 #define LAN966X_CUPHY_COMMON_CFG	0x0
45 #define		CUPHY_COMMON_CFG_RESET_N	BIT(0)
46 
47 struct mscc_miim_info {
48 	unsigned int phy_reset_offset;
49 	unsigned int phy_reset_bits;
50 };
51 
52 struct mscc_miim_dev {
53 	struct regmap *regs;
54 	int mii_status_offset;
55 	bool ignore_read_errors;
56 	struct regmap *phy_regs;
57 	const struct mscc_miim_info *info;
58 	struct clk *clk;
59 	u32 bus_freq;
60 };
61 
62 /* When high resolution timers aren't built-in: we can't use usleep_range() as
63  * we would sleep way too long. Use udelay() instead.
64  */
65 #define mscc_readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us)\
66 ({									  \
67 	if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS))			  \
68 		readx_poll_timeout_atomic(op, addr, val, cond, delay_us,  \
69 					  timeout_us);			  \
70 	readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us);	  \
71 })
72 
73 static int mscc_miim_status(struct mii_bus *bus)
74 {
75 	struct mscc_miim_dev *miim = bus->priv;
76 	int val, ret;
77 
78 	ret = regmap_read(miim->regs,
79 			  MSCC_MIIM_REG_STATUS + miim->mii_status_offset, &val);
80 	if (ret < 0) {
81 		WARN_ONCE(1, "mscc miim status read error %d\n", ret);
82 		return ret;
83 	}
84 
85 	return val;
86 }
87 
88 static int mscc_miim_wait_ready(struct mii_bus *bus)
89 {
90 	u32 val;
91 
92 	return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
93 				       !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
94 				       10000);
95 }
96 
97 static int mscc_miim_wait_pending(struct mii_bus *bus)
98 {
99 	u32 val;
100 
101 	return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
102 				       !(val & MSCC_MIIM_STATUS_STAT_PENDING),
103 				       50, 10000);
104 }
105 
106 static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
107 {
108 	struct mscc_miim_dev *miim = bus->priv;
109 	u32 val;
110 	int ret;
111 
112 	ret = mscc_miim_wait_pending(bus);
113 	if (ret)
114 		goto out;
115 
116 	ret = regmap_write(miim->regs,
117 			   MSCC_MIIM_REG_CMD + miim->mii_status_offset,
118 			   MSCC_MIIM_CMD_VLD |
119 			   (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
120 			   (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
121 			   MSCC_MIIM_CMD_OPR_READ);
122 
123 	if (ret < 0) {
124 		WARN_ONCE(1, "mscc miim write cmd reg error %d\n", ret);
125 		goto out;
126 	}
127 
128 	ret = mscc_miim_wait_ready(bus);
129 	if (ret)
130 		goto out;
131 
132 	ret = regmap_read(miim->regs,
133 			  MSCC_MIIM_REG_DATA + miim->mii_status_offset, &val);
134 	if (ret < 0) {
135 		WARN_ONCE(1, "mscc miim read data reg error %d\n", ret);
136 		goto out;
137 	}
138 
139 	if (!miim->ignore_read_errors && !!(val & MSCC_MIIM_DATA_ERROR)) {
140 		ret = -EIO;
141 		goto out;
142 	}
143 
144 	ret = val & 0xFFFF;
145 out:
146 	return ret;
147 }
148 
149 static int mscc_miim_write(struct mii_bus *bus, int mii_id,
150 			   int regnum, u16 value)
151 {
152 	struct mscc_miim_dev *miim = bus->priv;
153 	int ret;
154 
155 	ret = mscc_miim_wait_pending(bus);
156 	if (ret < 0)
157 		goto out;
158 
159 	ret = regmap_write(miim->regs,
160 			   MSCC_MIIM_REG_CMD + miim->mii_status_offset,
161 			   MSCC_MIIM_CMD_VLD |
162 			   (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
163 			   (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
164 			   (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
165 			   MSCC_MIIM_CMD_OPR_WRITE);
166 
167 	if (ret < 0)
168 		WARN_ONCE(1, "mscc miim write error %d\n", ret);
169 out:
170 	return ret;
171 }
172 
173 static int mscc_miim_reset(struct mii_bus *bus)
174 {
175 	struct mscc_miim_dev *miim = bus->priv;
176 	unsigned int offset, bits;
177 	int ret;
178 
179 	if (!miim->phy_regs)
180 		return 0;
181 
182 	offset = miim->info->phy_reset_offset;
183 	bits = miim->info->phy_reset_bits;
184 
185 	ret = regmap_update_bits(miim->phy_regs, offset, bits, 0);
186 	if (ret < 0) {
187 		WARN_ONCE(1, "mscc reset set error %d\n", ret);
188 		return ret;
189 	}
190 
191 	ret = regmap_update_bits(miim->phy_regs, offset, bits, bits);
192 	if (ret < 0) {
193 		WARN_ONCE(1, "mscc reset clear error %d\n", ret);
194 		return ret;
195 	}
196 
197 	mdelay(500);
198 
199 	return 0;
200 }
201 
202 static const struct regmap_config mscc_miim_regmap_config = {
203 	.reg_bits	= 32,
204 	.val_bits	= 32,
205 	.reg_stride	= 4,
206 };
207 
208 static const struct regmap_config mscc_miim_phy_regmap_config = {
209 	.reg_bits	= 32,
210 	.val_bits	= 32,
211 	.reg_stride	= 4,
212 	.name		= "phy",
213 };
214 
215 int mscc_miim_setup(struct device *dev, struct mii_bus **pbus, const char *name,
216 		    struct regmap *mii_regmap, int status_offset,
217 		    bool ignore_read_errors)
218 {
219 	struct mscc_miim_dev *miim;
220 	struct mii_bus *bus;
221 
222 	bus = devm_mdiobus_alloc_size(dev, sizeof(*miim));
223 	if (!bus)
224 		return -ENOMEM;
225 
226 	bus->name = name;
227 	bus->read = mscc_miim_read;
228 	bus->write = mscc_miim_write;
229 	bus->reset = mscc_miim_reset;
230 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
231 	bus->parent = dev;
232 
233 	miim = bus->priv;
234 
235 	*pbus = bus;
236 
237 	miim->regs = mii_regmap;
238 	miim->mii_status_offset = status_offset;
239 	miim->ignore_read_errors = ignore_read_errors;
240 
241 	*pbus = bus;
242 
243 	return 0;
244 }
245 EXPORT_SYMBOL(mscc_miim_setup);
246 
247 static int mscc_miim_clk_set(struct mii_bus *bus)
248 {
249 	struct mscc_miim_dev *miim = bus->priv;
250 	unsigned long rate;
251 	u32 div;
252 
253 	/* Keep the current settings */
254 	if (!miim->bus_freq)
255 		return 0;
256 
257 	rate = clk_get_rate(miim->clk);
258 
259 	div = DIV_ROUND_UP(rate, 2 * miim->bus_freq) - 1;
260 	if (div == 0 || div & ~MSCC_MIIM_CFG_PRESCALE_MASK) {
261 		dev_err(&bus->dev, "Incorrect MDIO clock frequency\n");
262 		return -EINVAL;
263 	}
264 
265 	return regmap_update_bits(miim->regs, MSCC_MIIM_REG_CFG,
266 				  MSCC_MIIM_CFG_PRESCALE_MASK, div);
267 }
268 
269 static int mscc_miim_probe(struct platform_device *pdev)
270 {
271 	struct device_node *np = pdev->dev.of_node;
272 	struct regmap *mii_regmap, *phy_regmap;
273 	struct device *dev = &pdev->dev;
274 	struct mscc_miim_dev *miim;
275 	struct mii_bus *bus;
276 	int ret;
277 
278 	mii_regmap = ocelot_regmap_from_resource(pdev, 0,
279 						 &mscc_miim_regmap_config);
280 	if (IS_ERR(mii_regmap))
281 		return dev_err_probe(dev, PTR_ERR(mii_regmap),
282 				     "Unable to create MIIM regmap\n");
283 
284 	/* This resource is optional */
285 	phy_regmap = ocelot_regmap_from_resource_optional(pdev, 1,
286 						 &mscc_miim_phy_regmap_config);
287 	if (IS_ERR(phy_regmap))
288 		return dev_err_probe(dev, PTR_ERR(phy_regmap),
289 				     "Unable to create phy register regmap\n");
290 
291 	ret = mscc_miim_setup(dev, &bus, "mscc_miim", mii_regmap, 0, false);
292 	if (ret < 0) {
293 		dev_err(dev, "Unable to setup the MDIO bus\n");
294 		return ret;
295 	}
296 
297 	miim = bus->priv;
298 	miim->phy_regs = phy_regmap;
299 
300 	miim->info = device_get_match_data(dev);
301 	if (!miim->info)
302 		return -EINVAL;
303 
304 	miim->clk = devm_clk_get_optional(dev, NULL);
305 	if (IS_ERR(miim->clk))
306 		return PTR_ERR(miim->clk);
307 
308 	of_property_read_u32(np, "clock-frequency", &miim->bus_freq);
309 
310 	if (miim->bus_freq && !miim->clk) {
311 		dev_err(dev, "cannot use clock-frequency without a clock\n");
312 		return -EINVAL;
313 	}
314 
315 	ret = clk_prepare_enable(miim->clk);
316 	if (ret)
317 		return ret;
318 
319 	ret = mscc_miim_clk_set(bus);
320 	if (ret)
321 		goto out_disable_clk;
322 
323 	ret = of_mdiobus_register(bus, np);
324 	if (ret < 0) {
325 		dev_err(dev, "Cannot register MDIO bus (%d)\n", ret);
326 		goto out_disable_clk;
327 	}
328 
329 	platform_set_drvdata(pdev, bus);
330 
331 	return 0;
332 
333 out_disable_clk:
334 	clk_disable_unprepare(miim->clk);
335 	return ret;
336 }
337 
338 static int mscc_miim_remove(struct platform_device *pdev)
339 {
340 	struct mii_bus *bus = platform_get_drvdata(pdev);
341 	struct mscc_miim_dev *miim = bus->priv;
342 
343 	clk_disable_unprepare(miim->clk);
344 	mdiobus_unregister(bus);
345 
346 	return 0;
347 }
348 
349 static const struct mscc_miim_info mscc_ocelot_miim_info = {
350 	.phy_reset_offset = MSCC_PHY_REG_PHY_CFG,
351 	.phy_reset_bits = PHY_CFG_PHY_ENA | PHY_CFG_PHY_COMMON_RESET |
352 			  PHY_CFG_PHY_RESET,
353 };
354 
355 static const struct mscc_miim_info microchip_lan966x_miim_info = {
356 	.phy_reset_offset = LAN966X_CUPHY_COMMON_CFG,
357 	.phy_reset_bits = CUPHY_COMMON_CFG_RESET_N,
358 };
359 
360 static const struct of_device_id mscc_miim_match[] = {
361 	{
362 		.compatible = "mscc,ocelot-miim",
363 		.data = &mscc_ocelot_miim_info
364 	}, {
365 		.compatible = "microchip,lan966x-miim",
366 		.data = &microchip_lan966x_miim_info
367 	},
368 	{ }
369 };
370 MODULE_DEVICE_TABLE(of, mscc_miim_match);
371 
372 static struct platform_driver mscc_miim_driver = {
373 	.probe = mscc_miim_probe,
374 	.remove = mscc_miim_remove,
375 	.driver = {
376 		.name = "mscc-miim",
377 		.of_match_table = mscc_miim_match,
378 	},
379 };
380 
381 module_platform_driver(mscc_miim_driver);
382 
383 MODULE_DESCRIPTION("Microsemi MIIM driver");
384 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
385 MODULE_LICENSE("Dual MIT/GPL");
386