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 struct regmap *phy_regs;
56 const struct mscc_miim_info *info;
57 struct clk *clk;
58 u32 bus_freq;
59 };
60
61 /* When high resolution timers aren't built-in: we can't use usleep_range() as
62 * we would sleep way too long. Use udelay() instead.
63 */
64 #define mscc_readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us)\
65 ({ \
66 if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS)) \
67 readx_poll_timeout_atomic(op, addr, val, cond, delay_us, \
68 timeout_us); \
69 readx_poll_timeout(op, addr, val, cond, delay_us, timeout_us); \
70 })
71
mscc_miim_status(struct mii_bus * bus)72 static int mscc_miim_status(struct mii_bus *bus)
73 {
74 struct mscc_miim_dev *miim = bus->priv;
75 int val, ret;
76
77 ret = regmap_read(miim->regs,
78 MSCC_MIIM_REG_STATUS + miim->mii_status_offset, &val);
79 if (ret < 0) {
80 WARN_ONCE(1, "mscc miim status read error %d\n", ret);
81 return ret;
82 }
83
84 return val;
85 }
86
mscc_miim_wait_ready(struct mii_bus * bus)87 static int mscc_miim_wait_ready(struct mii_bus *bus)
88 {
89 u32 val;
90
91 return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
92 !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
93 10000);
94 }
95
mscc_miim_wait_pending(struct mii_bus * bus)96 static int mscc_miim_wait_pending(struct mii_bus *bus)
97 {
98 u32 val;
99
100 return mscc_readx_poll_timeout(mscc_miim_status, bus, val,
101 !(val & MSCC_MIIM_STATUS_STAT_PENDING),
102 50, 10000);
103 }
104
mscc_miim_read(struct mii_bus * bus,int mii_id,int regnum)105 static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
106 {
107 struct mscc_miim_dev *miim = bus->priv;
108 u32 val;
109 int ret;
110
111 if (regnum & MII_ADDR_C45)
112 return -EOPNOTSUPP;
113
114 ret = mscc_miim_wait_pending(bus);
115 if (ret)
116 goto out;
117
118 ret = regmap_write(miim->regs,
119 MSCC_MIIM_REG_CMD + miim->mii_status_offset,
120 MSCC_MIIM_CMD_VLD |
121 (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
122 (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
123 MSCC_MIIM_CMD_OPR_READ);
124
125 if (ret < 0) {
126 WARN_ONCE(1, "mscc miim write cmd reg error %d\n", ret);
127 goto out;
128 }
129
130 ret = mscc_miim_wait_ready(bus);
131 if (ret)
132 goto out;
133
134 ret = regmap_read(miim->regs,
135 MSCC_MIIM_REG_DATA + miim->mii_status_offset, &val);
136 if (ret < 0) {
137 WARN_ONCE(1, "mscc miim read data reg error %d\n", ret);
138 goto out;
139 }
140
141 if (val & MSCC_MIIM_DATA_ERROR) {
142 ret = -EIO;
143 goto out;
144 }
145
146 ret = val & 0xFFFF;
147 out:
148 return ret;
149 }
150
mscc_miim_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)151 static int mscc_miim_write(struct mii_bus *bus, int mii_id,
152 int regnum, u16 value)
153 {
154 struct mscc_miim_dev *miim = bus->priv;
155 int ret;
156
157 if (regnum & MII_ADDR_C45)
158 return -EOPNOTSUPP;
159
160 ret = mscc_miim_wait_pending(bus);
161 if (ret < 0)
162 goto out;
163
164 ret = regmap_write(miim->regs,
165 MSCC_MIIM_REG_CMD + miim->mii_status_offset,
166 MSCC_MIIM_CMD_VLD |
167 (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
168 (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
169 (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
170 MSCC_MIIM_CMD_OPR_WRITE);
171
172 if (ret < 0)
173 WARN_ONCE(1, "mscc miim write error %d\n", ret);
174 out:
175 return ret;
176 }
177
mscc_miim_reset(struct mii_bus * bus)178 static int mscc_miim_reset(struct mii_bus *bus)
179 {
180 struct mscc_miim_dev *miim = bus->priv;
181 unsigned int offset, bits;
182 int ret;
183
184 if (!miim->phy_regs)
185 return 0;
186
187 offset = miim->info->phy_reset_offset;
188 bits = miim->info->phy_reset_bits;
189
190 ret = regmap_update_bits(miim->phy_regs, offset, bits, 0);
191 if (ret < 0) {
192 WARN_ONCE(1, "mscc reset set error %d\n", ret);
193 return ret;
194 }
195
196 ret = regmap_update_bits(miim->phy_regs, offset, bits, bits);
197 if (ret < 0) {
198 WARN_ONCE(1, "mscc reset clear error %d\n", ret);
199 return ret;
200 }
201
202 mdelay(500);
203
204 return 0;
205 }
206
207 static const struct regmap_config mscc_miim_regmap_config = {
208 .reg_bits = 32,
209 .val_bits = 32,
210 .reg_stride = 4,
211 };
212
213 static const struct regmap_config mscc_miim_phy_regmap_config = {
214 .reg_bits = 32,
215 .val_bits = 32,
216 .reg_stride = 4,
217 .name = "phy",
218 };
219
mscc_miim_setup(struct device * dev,struct mii_bus ** pbus,const char * name,struct regmap * mii_regmap,int status_offset)220 int mscc_miim_setup(struct device *dev, struct mii_bus **pbus, const char *name,
221 struct regmap *mii_regmap, int status_offset)
222 {
223 struct mscc_miim_dev *miim;
224 struct mii_bus *bus;
225
226 bus = devm_mdiobus_alloc_size(dev, sizeof(*miim));
227 if (!bus)
228 return -ENOMEM;
229
230 bus->name = name;
231 bus->read = mscc_miim_read;
232 bus->write = mscc_miim_write;
233 bus->reset = mscc_miim_reset;
234 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
235 bus->parent = dev;
236
237 miim = bus->priv;
238
239 *pbus = bus;
240
241 miim->regs = mii_regmap;
242 miim->mii_status_offset = status_offset;
243
244 *pbus = bus;
245
246 return 0;
247 }
248 EXPORT_SYMBOL(mscc_miim_setup);
249
mscc_miim_clk_set(struct mii_bus * bus)250 static int mscc_miim_clk_set(struct mii_bus *bus)
251 {
252 struct mscc_miim_dev *miim = bus->priv;
253 unsigned long rate;
254 u32 div;
255
256 /* Keep the current settings */
257 if (!miim->bus_freq)
258 return 0;
259
260 rate = clk_get_rate(miim->clk);
261
262 div = DIV_ROUND_UP(rate, 2 * miim->bus_freq) - 1;
263 if (div == 0 || div & ~MSCC_MIIM_CFG_PRESCALE_MASK) {
264 dev_err(&bus->dev, "Incorrect MDIO clock frequency\n");
265 return -EINVAL;
266 }
267
268 return regmap_update_bits(miim->regs, MSCC_MIIM_REG_CFG,
269 MSCC_MIIM_CFG_PRESCALE_MASK, div);
270 }
271
mscc_miim_probe(struct platform_device * pdev)272 static int mscc_miim_probe(struct platform_device *pdev)
273 {
274 struct device_node *np = pdev->dev.of_node;
275 struct regmap *mii_regmap, *phy_regmap;
276 struct device *dev = &pdev->dev;
277 struct mscc_miim_dev *miim;
278 struct mii_bus *bus;
279 int ret;
280
281 mii_regmap = ocelot_regmap_from_resource(pdev, 0,
282 &mscc_miim_regmap_config);
283 if (IS_ERR(mii_regmap))
284 return dev_err_probe(dev, PTR_ERR(mii_regmap),
285 "Unable to create MIIM regmap\n");
286
287 /* This resource is optional */
288 phy_regmap = ocelot_regmap_from_resource_optional(pdev, 1,
289 &mscc_miim_phy_regmap_config);
290 if (IS_ERR(phy_regmap))
291 return dev_err_probe(dev, PTR_ERR(phy_regmap),
292 "Unable to create phy register regmap\n");
293
294 ret = mscc_miim_setup(dev, &bus, "mscc_miim", mii_regmap, 0);
295 if (ret < 0) {
296 dev_err(dev, "Unable to setup the MDIO bus\n");
297 return ret;
298 }
299
300 miim = bus->priv;
301 miim->phy_regs = phy_regmap;
302
303 miim->info = device_get_match_data(dev);
304 if (!miim->info)
305 return -EINVAL;
306
307 miim->clk = devm_clk_get_optional(dev, NULL);
308 if (IS_ERR(miim->clk))
309 return PTR_ERR(miim->clk);
310
311 of_property_read_u32(np, "clock-frequency", &miim->bus_freq);
312
313 if (miim->bus_freq && !miim->clk) {
314 dev_err(dev, "cannot use clock-frequency without a clock\n");
315 return -EINVAL;
316 }
317
318 ret = clk_prepare_enable(miim->clk);
319 if (ret)
320 return ret;
321
322 ret = mscc_miim_clk_set(bus);
323 if (ret)
324 goto out_disable_clk;
325
326 ret = of_mdiobus_register(bus, np);
327 if (ret < 0) {
328 dev_err(dev, "Cannot register MDIO bus (%d)\n", ret);
329 goto out_disable_clk;
330 }
331
332 platform_set_drvdata(pdev, bus);
333
334 return 0;
335
336 out_disable_clk:
337 clk_disable_unprepare(miim->clk);
338 return ret;
339 }
340
mscc_miim_remove(struct platform_device * pdev)341 static int mscc_miim_remove(struct platform_device *pdev)
342 {
343 struct mii_bus *bus = platform_get_drvdata(pdev);
344 struct mscc_miim_dev *miim = bus->priv;
345
346 clk_disable_unprepare(miim->clk);
347 mdiobus_unregister(bus);
348
349 return 0;
350 }
351
352 static const struct mscc_miim_info mscc_ocelot_miim_info = {
353 .phy_reset_offset = MSCC_PHY_REG_PHY_CFG,
354 .phy_reset_bits = PHY_CFG_PHY_ENA | PHY_CFG_PHY_COMMON_RESET |
355 PHY_CFG_PHY_RESET,
356 };
357
358 static const struct mscc_miim_info microchip_lan966x_miim_info = {
359 .phy_reset_offset = LAN966X_CUPHY_COMMON_CFG,
360 .phy_reset_bits = CUPHY_COMMON_CFG_RESET_N,
361 };
362
363 static const struct of_device_id mscc_miim_match[] = {
364 {
365 .compatible = "mscc,ocelot-miim",
366 .data = &mscc_ocelot_miim_info
367 }, {
368 .compatible = "microchip,lan966x-miim",
369 .data = µchip_lan966x_miim_info
370 },
371 { }
372 };
373 MODULE_DEVICE_TABLE(of, mscc_miim_match);
374
375 static struct platform_driver mscc_miim_driver = {
376 .probe = mscc_miim_probe,
377 .remove = mscc_miim_remove,
378 .driver = {
379 .name = "mscc-miim",
380 .of_match_table = mscc_miim_match,
381 },
382 };
383
384 module_platform_driver(mscc_miim_driver);
385
386 MODULE_DESCRIPTION("Microsemi MIIM driver");
387 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
388 MODULE_LICENSE("Dual MIT/GPL");
389