1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Rockchip emmc PHY driver
4 *
5 * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com>
6 * Copyright (C) 2016 ROCKCHIP, Inc.
7 */
8
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/mfd/syscon.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/phy/phy.h>
16 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
18
19 /*
20 * The higher 16-bit of this register is used for write protection
21 * only if BIT(x + 16) set to 1 the BIT(x) can be written.
22 */
23 #define HIWORD_UPDATE(val, mask, shift) \
24 ((val) << (shift) | (mask) << ((shift) + 16))
25
26 /* Register definition */
27 #define GRF_EMMCPHY_CON0 0x0
28 #define GRF_EMMCPHY_CON1 0x4
29 #define GRF_EMMCPHY_CON2 0x8
30 #define GRF_EMMCPHY_CON3 0xc
31 #define GRF_EMMCPHY_CON4 0x10
32 #define GRF_EMMCPHY_CON5 0x14
33 #define GRF_EMMCPHY_CON6 0x18
34 #define GRF_EMMCPHY_STATUS 0x20
35
36 #define PHYCTRL_PDB_MASK 0x1
37 #define PHYCTRL_PDB_SHIFT 0x0
38 #define PHYCTRL_PDB_PWR_ON 0x1
39 #define PHYCTRL_PDB_PWR_OFF 0x0
40 #define PHYCTRL_ENDLL_MASK 0x1
41 #define PHYCTRL_ENDLL_SHIFT 0x1
42 #define PHYCTRL_ENDLL_ENABLE 0x1
43 #define PHYCTRL_ENDLL_DISABLE 0x0
44 #define PHYCTRL_CALDONE_MASK 0x1
45 #define PHYCTRL_CALDONE_SHIFT 0x6
46 #define PHYCTRL_CALDONE_DONE 0x1
47 #define PHYCTRL_CALDONE_GOING 0x0
48 #define PHYCTRL_DLLRDY_MASK 0x1
49 #define PHYCTRL_DLLRDY_SHIFT 0x5
50 #define PHYCTRL_DLLRDY_DONE 0x1
51 #define PHYCTRL_DLLRDY_GOING 0x0
52 #define PHYCTRL_FREQSEL_200M 0x0
53 #define PHYCTRL_FREQSEL_50M 0x1
54 #define PHYCTRL_FREQSEL_100M 0x2
55 #define PHYCTRL_FREQSEL_150M 0x3
56 #define PHYCTRL_FREQSEL_MASK 0x3
57 #define PHYCTRL_FREQSEL_SHIFT 0xc
58 #define PHYCTRL_DR_MASK 0x7
59 #define PHYCTRL_DR_SHIFT 0x4
60 #define PHYCTRL_DR_50OHM 0x0
61 #define PHYCTRL_DR_33OHM 0x1
62 #define PHYCTRL_DR_66OHM 0x2
63 #define PHYCTRL_DR_100OHM 0x3
64 #define PHYCTRL_DR_40OHM 0x4
65 #define PHYCTRL_OTAPDLYENA 0x1
66 #define PHYCTRL_OTAPDLYENA_MASK 0x1
67 #define PHYCTRL_OTAPDLYENA_SHIFT 0xb
68 #define PHYCTRL_OTAPDLYSEL_DEFAULT 0x4
69 #define PHYCTRL_OTAPDLYSEL_MAXVALUE 0xf
70 #define PHYCTRL_OTAPDLYSEL_MASK 0xf
71 #define PHYCTRL_OTAPDLYSEL_SHIFT 0x7
72 #define PHYCTRL_REN_STRB_DISABLE 0x0
73 #define PHYCTRL_REN_STRB_ENABLE 0x1
74 #define PHYCTRL_REN_STRB_MASK 0x1
75 #define PHYCTRL_REN_STRB_SHIFT 0x9
76
77 #define PHYCTRL_IS_CALDONE(x) \
78 ((((x) >> PHYCTRL_CALDONE_SHIFT) & \
79 PHYCTRL_CALDONE_MASK) == PHYCTRL_CALDONE_DONE)
80 #define PHYCTRL_IS_DLLRDY(x) \
81 ((((x) >> PHYCTRL_DLLRDY_SHIFT) & \
82 PHYCTRL_DLLRDY_MASK) == PHYCTRL_DLLRDY_DONE)
83
84 struct rockchip_emmc_phy {
85 unsigned int reg_offset;
86 struct regmap *reg_base;
87 struct clk *emmcclk;
88 unsigned int drive_impedance;
89 unsigned int enable_strobe_pulldown;
90 unsigned int output_tapdelay_select;
91 };
92
rockchip_emmc_phy_power(struct phy * phy,bool on_off)93 static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
94 {
95 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
96 unsigned int caldone;
97 unsigned int dllrdy;
98 unsigned int freqsel = PHYCTRL_FREQSEL_200M;
99 unsigned long rate;
100 int ret;
101
102 /*
103 * Keep phyctrl_pdb and phyctrl_endll low to allow
104 * initialization of CALIO state M/C DFFs
105 */
106 regmap_write(rk_phy->reg_base,
107 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
108 HIWORD_UPDATE(PHYCTRL_PDB_PWR_OFF,
109 PHYCTRL_PDB_MASK,
110 PHYCTRL_PDB_SHIFT));
111 regmap_write(rk_phy->reg_base,
112 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
113 HIWORD_UPDATE(PHYCTRL_ENDLL_DISABLE,
114 PHYCTRL_ENDLL_MASK,
115 PHYCTRL_ENDLL_SHIFT));
116
117 /* Already finish power_off above */
118 if (on_off == PHYCTRL_PDB_PWR_OFF)
119 return 0;
120
121 rate = clk_get_rate(rk_phy->emmcclk);
122
123 if (rate != 0) {
124 unsigned long ideal_rate;
125 unsigned long diff;
126
127 switch (rate) {
128 case 1 ... 74999999:
129 ideal_rate = 50000000;
130 freqsel = PHYCTRL_FREQSEL_50M;
131 break;
132 case 75000000 ... 124999999:
133 ideal_rate = 100000000;
134 freqsel = PHYCTRL_FREQSEL_100M;
135 break;
136 case 125000000 ... 174999999:
137 ideal_rate = 150000000;
138 freqsel = PHYCTRL_FREQSEL_150M;
139 break;
140 default:
141 ideal_rate = 200000000;
142 break;
143 }
144
145 diff = (rate > ideal_rate) ?
146 rate - ideal_rate : ideal_rate - rate;
147
148 /*
149 * In order for tuning delays to be accurate we need to be
150 * pretty spot on for the DLL range, so warn if we're too
151 * far off. Also warn if we're above the 200 MHz max. Don't
152 * warn for really slow rates since we won't be tuning then.
153 */
154 if ((rate > 50000000 && diff > 15000000) || (rate > 200000000))
155 dev_warn(&phy->dev, "Unsupported rate: %lu\n", rate);
156 }
157
158 /*
159 * According to the user manual, calpad calibration
160 * cycle takes more than 2us without the minimal recommended
161 * value, so we may need a little margin here
162 */
163 udelay(3);
164 regmap_write(rk_phy->reg_base,
165 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
166 HIWORD_UPDATE(PHYCTRL_PDB_PWR_ON,
167 PHYCTRL_PDB_MASK,
168 PHYCTRL_PDB_SHIFT));
169
170 /*
171 * According to the user manual, it asks driver to wait 5us for
172 * calpad busy trimming. However it is documented that this value is
173 * PVT(A.K.A process,voltage and temperature) relevant, so some
174 * failure cases are found which indicates we should be more tolerant
175 * to calpad busy trimming.
176 */
177 ret = regmap_read_poll_timeout(rk_phy->reg_base,
178 rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
179 caldone, PHYCTRL_IS_CALDONE(caldone),
180 0, 50);
181 if (ret) {
182 pr_err("%s: caldone failed, ret=%d\n", __func__, ret);
183 return ret;
184 }
185
186 /* Set the frequency of the DLL operation */
187 regmap_write(rk_phy->reg_base,
188 rk_phy->reg_offset + GRF_EMMCPHY_CON0,
189 HIWORD_UPDATE(freqsel, PHYCTRL_FREQSEL_MASK,
190 PHYCTRL_FREQSEL_SHIFT));
191
192 /* Turn on the DLL */
193 regmap_write(rk_phy->reg_base,
194 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
195 HIWORD_UPDATE(PHYCTRL_ENDLL_ENABLE,
196 PHYCTRL_ENDLL_MASK,
197 PHYCTRL_ENDLL_SHIFT));
198
199 /*
200 * We turned on the DLL even though the rate was 0 because we the
201 * clock might be turned on later. ...but we can't wait for the DLL
202 * to lock when the rate is 0 because it will never lock with no
203 * input clock.
204 *
205 * Technically we should be checking the lock later when the clock
206 * is turned on, but for now we won't.
207 */
208 if (rate == 0)
209 return 0;
210
211 /*
212 * After enabling analog DLL circuits docs say that we need 10.2 us if
213 * our source clock is at 50 MHz and that lock time scales linearly
214 * with clock speed. If we are powering on the PHY and the card clock
215 * is super slow (like 100 kHZ) this could take as long as 5.1 ms as
216 * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
217 * Hopefully we won't be running at 100 kHz, but we should still make
218 * sure we wait long enough.
219 *
220 * NOTE: There appear to be corner cases where the DLL seems to take
221 * extra long to lock for reasons that aren't understood. In some
222 * extreme cases we've seen it take up to over 10ms (!). We'll be
223 * generous and give it 50ms.
224 */
225 ret = regmap_read_poll_timeout(rk_phy->reg_base,
226 rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
227 dllrdy, PHYCTRL_IS_DLLRDY(dllrdy),
228 0, 50 * USEC_PER_MSEC);
229 if (ret) {
230 pr_err("%s: dllrdy failed. ret=%d\n", __func__, ret);
231 return ret;
232 }
233
234 return 0;
235 }
236
rockchip_emmc_phy_init(struct phy * phy)237 static int rockchip_emmc_phy_init(struct phy *phy)
238 {
239 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
240 int ret = 0;
241
242 /*
243 * We purposely get the clock here and not in probe to avoid the
244 * circular dependency problem. We expect:
245 * - PHY driver to probe
246 * - SDHCI driver to start probe
247 * - SDHCI driver to register it's clock
248 * - SDHCI driver to get the PHY
249 * - SDHCI driver to init the PHY
250 *
251 * The clock is optional, using clk_get_optional() to get the clock
252 * and do error processing if the return value != NULL
253 *
254 * NOTE: we don't do anything special for EPROBE_DEFER here. Given the
255 * above expected use case, EPROBE_DEFER isn't sensible to expect, so
256 * it's just like any other error.
257 */
258 rk_phy->emmcclk = clk_get_optional(&phy->dev, "emmcclk");
259 if (IS_ERR(rk_phy->emmcclk)) {
260 ret = PTR_ERR(rk_phy->emmcclk);
261 dev_err(&phy->dev, "Error getting emmcclk: %d\n", ret);
262 rk_phy->emmcclk = NULL;
263 }
264
265 return ret;
266 }
267
rockchip_emmc_phy_exit(struct phy * phy)268 static int rockchip_emmc_phy_exit(struct phy *phy)
269 {
270 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
271
272 clk_put(rk_phy->emmcclk);
273
274 return 0;
275 }
276
rockchip_emmc_phy_power_off(struct phy * phy)277 static int rockchip_emmc_phy_power_off(struct phy *phy)
278 {
279 /* Power down emmc phy analog blocks */
280 return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_OFF);
281 }
282
rockchip_emmc_phy_power_on(struct phy * phy)283 static int rockchip_emmc_phy_power_on(struct phy *phy)
284 {
285 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
286
287 /* Drive impedance: from DTS */
288 regmap_write(rk_phy->reg_base,
289 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
290 HIWORD_UPDATE(rk_phy->drive_impedance,
291 PHYCTRL_DR_MASK,
292 PHYCTRL_DR_SHIFT));
293
294 /* Output tap delay: enable */
295 regmap_write(rk_phy->reg_base,
296 rk_phy->reg_offset + GRF_EMMCPHY_CON0,
297 HIWORD_UPDATE(PHYCTRL_OTAPDLYENA,
298 PHYCTRL_OTAPDLYENA_MASK,
299 PHYCTRL_OTAPDLYENA_SHIFT));
300
301 /* Output tap delay */
302 regmap_write(rk_phy->reg_base,
303 rk_phy->reg_offset + GRF_EMMCPHY_CON0,
304 HIWORD_UPDATE(rk_phy->output_tapdelay_select,
305 PHYCTRL_OTAPDLYSEL_MASK,
306 PHYCTRL_OTAPDLYSEL_SHIFT));
307
308 /* Internal pull-down for strobe line */
309 regmap_write(rk_phy->reg_base,
310 rk_phy->reg_offset + GRF_EMMCPHY_CON2,
311 HIWORD_UPDATE(rk_phy->enable_strobe_pulldown,
312 PHYCTRL_REN_STRB_MASK,
313 PHYCTRL_REN_STRB_SHIFT));
314
315 /* Power up emmc phy analog blocks */
316 return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_ON);
317 }
318
319 static const struct phy_ops ops = {
320 .init = rockchip_emmc_phy_init,
321 .exit = rockchip_emmc_phy_exit,
322 .power_on = rockchip_emmc_phy_power_on,
323 .power_off = rockchip_emmc_phy_power_off,
324 .owner = THIS_MODULE,
325 };
326
convert_drive_impedance_ohm(struct platform_device * pdev,u32 dr_ohm)327 static u32 convert_drive_impedance_ohm(struct platform_device *pdev, u32 dr_ohm)
328 {
329 switch (dr_ohm) {
330 case 100:
331 return PHYCTRL_DR_100OHM;
332 case 66:
333 return PHYCTRL_DR_66OHM;
334 case 50:
335 return PHYCTRL_DR_50OHM;
336 case 40:
337 return PHYCTRL_DR_40OHM;
338 case 33:
339 return PHYCTRL_DR_33OHM;
340 }
341
342 dev_warn(&pdev->dev, "Invalid value %u for drive-impedance-ohm.\n",
343 dr_ohm);
344 return PHYCTRL_DR_50OHM;
345 }
346
rockchip_emmc_phy_probe(struct platform_device * pdev)347 static int rockchip_emmc_phy_probe(struct platform_device *pdev)
348 {
349 struct device *dev = &pdev->dev;
350 struct rockchip_emmc_phy *rk_phy;
351 struct phy *generic_phy;
352 struct phy_provider *phy_provider;
353 struct regmap *grf;
354 unsigned int reg_offset;
355 u32 val;
356
357 if (!dev->parent || !dev->parent->of_node)
358 return -ENODEV;
359
360 grf = syscon_node_to_regmap(dev->parent->of_node);
361 if (IS_ERR(grf)) {
362 dev_err(dev, "Missing rockchip,grf property\n");
363 return PTR_ERR(grf);
364 }
365
366 rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL);
367 if (!rk_phy)
368 return -ENOMEM;
369
370 if (of_property_read_u32(dev->of_node, "reg", ®_offset)) {
371 dev_err(dev, "missing reg property in node %pOFn\n",
372 dev->of_node);
373 return -EINVAL;
374 }
375
376 rk_phy->reg_offset = reg_offset;
377 rk_phy->reg_base = grf;
378 rk_phy->drive_impedance = PHYCTRL_DR_50OHM;
379 rk_phy->enable_strobe_pulldown = PHYCTRL_REN_STRB_DISABLE;
380 rk_phy->output_tapdelay_select = PHYCTRL_OTAPDLYSEL_DEFAULT;
381
382 if (!of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val))
383 rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, val);
384
385 if (of_property_read_bool(dev->of_node, "rockchip,enable-strobe-pulldown"))
386 rk_phy->enable_strobe_pulldown = PHYCTRL_REN_STRB_ENABLE;
387
388 if (!of_property_read_u32(dev->of_node, "rockchip,output-tapdelay-select", &val)) {
389 if (val <= PHYCTRL_OTAPDLYSEL_MAXVALUE)
390 rk_phy->output_tapdelay_select = val;
391 else
392 dev_err(dev, "output-tapdelay-select exceeds limit, apply default\n");
393 }
394
395 generic_phy = devm_phy_create(dev, dev->of_node, &ops);
396 if (IS_ERR(generic_phy)) {
397 dev_err(dev, "failed to create PHY\n");
398 return PTR_ERR(generic_phy);
399 }
400
401 phy_set_drvdata(generic_phy, rk_phy);
402 phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
403
404 return PTR_ERR_OR_ZERO(phy_provider);
405 }
406
407 static const struct of_device_id rockchip_emmc_phy_dt_ids[] = {
408 { .compatible = "rockchip,rk3399-emmc-phy" },
409 {}
410 };
411
412 MODULE_DEVICE_TABLE(of, rockchip_emmc_phy_dt_ids);
413
414 static struct platform_driver rockchip_emmc_driver = {
415 .probe = rockchip_emmc_phy_probe,
416 .driver = {
417 .name = "rockchip-emmc-phy",
418 .of_match_table = rockchip_emmc_phy_dt_ids,
419 },
420 };
421
422 module_platform_driver(rockchip_emmc_driver);
423
424 MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
425 MODULE_DESCRIPTION("Rockchip EMMC PHY driver");
426 MODULE_LICENSE("GPL v2");
427