2 * Rockchip emmc PHY driver
4 * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com>
5 * Copyright (C) 2016 ROCKCHIP, Inc.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
17 #include <linux/clk.h>
18 #include <linux/delay.h>
19 #include <linux/mfd/syscon.h>
20 #include <linux/module.h>
22 #include <linux/of_address.h>
23 #include <linux/phy/phy.h>
24 #include <linux/platform_device.h>
25 #include <linux/regmap.h>
28 * The higher 16-bit of this register is used for write protection
29 * only if BIT(x + 16) set to 1 the BIT(x) can be written.
31 #define HIWORD_UPDATE(val, mask, shift) \
32 ((val) << (shift) | (mask) << ((shift) + 16))
34 /* Register definition */
35 #define GRF_EMMCPHY_CON0 0x0
36 #define GRF_EMMCPHY_CON1 0x4
37 #define GRF_EMMCPHY_CON2 0x8
38 #define GRF_EMMCPHY_CON3 0xc
39 #define GRF_EMMCPHY_CON4 0x10
40 #define GRF_EMMCPHY_CON5 0x14
41 #define GRF_EMMCPHY_CON6 0x18
42 #define GRF_EMMCPHY_STATUS 0x20
44 #define PHYCTRL_PDB_MASK 0x1
45 #define PHYCTRL_PDB_SHIFT 0x0
46 #define PHYCTRL_PDB_PWR_ON 0x1
47 #define PHYCTRL_PDB_PWR_OFF 0x0
48 #define PHYCTRL_ENDLL_MASK 0x1
49 #define PHYCTRL_ENDLL_SHIFT 0x1
50 #define PHYCTRL_ENDLL_ENABLE 0x1
51 #define PHYCTRL_ENDLL_DISABLE 0x0
52 #define PHYCTRL_CALDONE_MASK 0x1
53 #define PHYCTRL_CALDONE_SHIFT 0x6
54 #define PHYCTRL_CALDONE_DONE 0x1
55 #define PHYCTRL_CALDONE_GOING 0x0
56 #define PHYCTRL_DLLRDY_MASK 0x1
57 #define PHYCTRL_DLLRDY_SHIFT 0x5
58 #define PHYCTRL_DLLRDY_DONE 0x1
59 #define PHYCTRL_DLLRDY_GOING 0x0
60 #define PHYCTRL_FREQSEL_200M 0x0
61 #define PHYCTRL_FREQSEL_50M 0x1
62 #define PHYCTRL_FREQSEL_100M 0x2
63 #define PHYCTRL_FREQSEL_150M 0x3
64 #define PHYCTRL_FREQSEL_MASK 0x3
65 #define PHYCTRL_FREQSEL_SHIFT 0xc
66 #define PHYCTRL_DR_MASK 0x7
67 #define PHYCTRL_DR_SHIFT 0x4
68 #define PHYCTRL_DR_50OHM 0x0
69 #define PHYCTRL_DR_33OHM 0x1
70 #define PHYCTRL_DR_66OHM 0x2
71 #define PHYCTRL_DR_100OHM 0x3
72 #define PHYCTRL_DR_40OHM 0x4
73 #define PHYCTRL_OTAPDLYENA 0x1
74 #define PHYCTRL_OTAPDLYENA_MASK 0x1
75 #define PHYCTRL_OTAPDLYENA_SHIFT 0xb
76 #define PHYCTRL_OTAPDLYSEL_MASK 0xf
77 #define PHYCTRL_OTAPDLYSEL_SHIFT 0x7
79 #define PHYCTRL_IS_CALDONE(x) \
80 ((((x) >> PHYCTRL_CALDONE_SHIFT) & \
81 PHYCTRL_CALDONE_MASK) == PHYCTRL_CALDONE_DONE)
83 struct rockchip_emmc_phy {
84 unsigned int reg_offset;
85 struct regmap *reg_base;
89 static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
91 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
94 unsigned int freqsel = PHYCTRL_FREQSEL_200M;
96 unsigned long timeout;
100 * Keep phyctrl_pdb and phyctrl_endll low to allow
101 * initialization of CALIO state M/C DFFs
103 regmap_write(rk_phy->reg_base,
104 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
105 HIWORD_UPDATE(PHYCTRL_PDB_PWR_OFF,
108 regmap_write(rk_phy->reg_base,
109 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
110 HIWORD_UPDATE(PHYCTRL_ENDLL_DISABLE,
112 PHYCTRL_ENDLL_SHIFT));
114 /* Already finish power_off above */
115 if (on_off == PHYCTRL_PDB_PWR_OFF)
118 rate = clk_get_rate(rk_phy->emmcclk);
121 unsigned long ideal_rate;
126 ideal_rate = 50000000;
127 freqsel = PHYCTRL_FREQSEL_50M;
129 case 75000000 ... 124999999:
130 ideal_rate = 100000000;
131 freqsel = PHYCTRL_FREQSEL_100M;
133 case 125000000 ... 174999999:
134 ideal_rate = 150000000;
135 freqsel = PHYCTRL_FREQSEL_150M;
138 ideal_rate = 200000000;
142 diff = (rate > ideal_rate) ?
143 rate - ideal_rate : ideal_rate - rate;
146 * In order for tuning delays to be accurate we need to be
147 * pretty spot on for the DLL range, so warn if we're too
148 * far off. Also warn if we're above the 200 MHz max. Don't
149 * warn for really slow rates since we won't be tuning then.
151 if ((rate > 50000000 && diff > 15000000) || (rate > 200000000))
152 dev_warn(&phy->dev, "Unsupported rate: %lu\n", rate);
156 * According to the user manual, calpad calibration
157 * cycle takes more than 2us without the minimal recommended
158 * value, so we may need a little margin here
161 regmap_write(rk_phy->reg_base,
162 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
163 HIWORD_UPDATE(PHYCTRL_PDB_PWR_ON,
168 * According to the user manual, it asks driver to wait 5us for
169 * calpad busy trimming. However it is documented that this value is
170 * PVT(A.K.A process,voltage and temperature) relevant, so some
171 * failure cases are found which indicates we should be more tolerant
172 * to calpad busy trimming.
174 ret = regmap_read_poll_timeout(rk_phy->reg_base,
175 rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
176 caldone, PHYCTRL_IS_CALDONE(caldone),
179 pr_err("%s: caldone failed, ret=%d\n", __func__, ret);
183 /* Set the frequency of the DLL operation */
184 regmap_write(rk_phy->reg_base,
185 rk_phy->reg_offset + GRF_EMMCPHY_CON0,
186 HIWORD_UPDATE(freqsel, PHYCTRL_FREQSEL_MASK,
187 PHYCTRL_FREQSEL_SHIFT));
189 /* Turn on the DLL */
190 regmap_write(rk_phy->reg_base,
191 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
192 HIWORD_UPDATE(PHYCTRL_ENDLL_ENABLE,
194 PHYCTRL_ENDLL_SHIFT));
197 * We turned on the DLL even though the rate was 0 because we the
198 * clock might be turned on later. ...but we can't wait for the DLL
199 * to lock when the rate is 0 because it will never lock with no
202 * Technically we should be checking the lock later when the clock
203 * is turned on, but for now we won't.
209 * After enabling analog DLL circuits docs say that we need 10.2 us if
210 * our source clock is at 50 MHz and that lock time scales linearly
211 * with clock speed. If we are powering on the PHY and the card clock
212 * is super slow (like 100 kHZ) this could take as long as 5.1 ms as
213 * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
214 * Hopefully we won't be running at 100 kHz, but we should still make
215 * sure we wait long enough.
217 * NOTE: There appear to be corner cases where the DLL seems to take
218 * extra long to lock for reasons that aren't understood. In some
219 * extreme cases we've seen it take up to over 10ms (!). We'll be
220 * generous and give it 50ms. We still busy wait here because:
221 * - In most cases it should be super fast.
222 * - This is not called lots during normal operation so it shouldn't
223 * be a power or performance problem to busy wait. We expect it
224 * only at boot / resume. In both cases, eMMC is probably on the
225 * critical path so busy waiting a little extra time should be OK.
227 timeout = jiffies + msecs_to_jiffies(50);
231 regmap_read(rk_phy->reg_base,
232 rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
234 dllrdy = (dllrdy >> PHYCTRL_DLLRDY_SHIFT) & PHYCTRL_DLLRDY_MASK;
235 if (dllrdy == PHYCTRL_DLLRDY_DONE)
237 } while (!time_after(jiffies, timeout));
239 if (dllrdy != PHYCTRL_DLLRDY_DONE) {
240 pr_err("rockchip_emmc_phy_power: dllrdy timeout.\n");
247 static int rockchip_emmc_phy_init(struct phy *phy)
249 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
253 * We purposely get the clock here and not in probe to avoid the
254 * circular dependency problem. We expect:
255 * - PHY driver to probe
256 * - SDHCI driver to start probe
257 * - SDHCI driver to register it's clock
258 * - SDHCI driver to get the PHY
259 * - SDHCI driver to init the PHY
261 * The clock is optional, so upon any error we just set to NULL.
263 * NOTE: we don't do anything special for EPROBE_DEFER here. Given the
264 * above expected use case, EPROBE_DEFER isn't sensible to expect, so
265 * it's just like any other error.
267 rk_phy->emmcclk = clk_get(&phy->dev, "emmcclk");
268 if (IS_ERR(rk_phy->emmcclk)) {
269 dev_dbg(&phy->dev, "Error getting emmcclk: %d\n", ret);
270 rk_phy->emmcclk = NULL;
276 static int rockchip_emmc_phy_exit(struct phy *phy)
278 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
280 clk_put(rk_phy->emmcclk);
285 static int rockchip_emmc_phy_power_off(struct phy *phy)
287 /* Power down emmc phy analog blocks */
288 return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_OFF);
291 static int rockchip_emmc_phy_power_on(struct phy *phy)
293 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
295 /* Drive impedance: 50 Ohm */
296 regmap_write(rk_phy->reg_base,
297 rk_phy->reg_offset + GRF_EMMCPHY_CON6,
298 HIWORD_UPDATE(PHYCTRL_DR_50OHM,
302 /* Output tap delay: enable */
303 regmap_write(rk_phy->reg_base,
304 rk_phy->reg_offset + GRF_EMMCPHY_CON0,
305 HIWORD_UPDATE(PHYCTRL_OTAPDLYENA,
306 PHYCTRL_OTAPDLYENA_MASK,
307 PHYCTRL_OTAPDLYENA_SHIFT));
309 /* Output tap delay */
310 regmap_write(rk_phy->reg_base,
311 rk_phy->reg_offset + GRF_EMMCPHY_CON0,
313 PHYCTRL_OTAPDLYSEL_MASK,
314 PHYCTRL_OTAPDLYSEL_SHIFT));
316 /* Power up emmc phy analog blocks */
317 return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_ON);
320 static const struct phy_ops ops = {
321 .init = rockchip_emmc_phy_init,
322 .exit = rockchip_emmc_phy_exit,
323 .power_on = rockchip_emmc_phy_power_on,
324 .power_off = rockchip_emmc_phy_power_off,
325 .owner = THIS_MODULE,
328 static int rockchip_emmc_phy_probe(struct platform_device *pdev)
330 struct device *dev = &pdev->dev;
331 struct rockchip_emmc_phy *rk_phy;
332 struct phy *generic_phy;
333 struct phy_provider *phy_provider;
335 unsigned int reg_offset;
337 if (!dev->parent || !dev->parent->of_node)
340 grf = syscon_node_to_regmap(dev->parent->of_node);
342 dev_err(dev, "Missing rockchip,grf property\n");
346 rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL);
350 if (of_property_read_u32(dev->of_node, "reg", ®_offset)) {
351 dev_err(dev, "missing reg property in node %s\n",
356 rk_phy->reg_offset = reg_offset;
357 rk_phy->reg_base = grf;
359 generic_phy = devm_phy_create(dev, dev->of_node, &ops);
360 if (IS_ERR(generic_phy)) {
361 dev_err(dev, "failed to create PHY\n");
362 return PTR_ERR(generic_phy);
365 phy_set_drvdata(generic_phy, rk_phy);
366 phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
368 return PTR_ERR_OR_ZERO(phy_provider);
371 static const struct of_device_id rockchip_emmc_phy_dt_ids[] = {
372 { .compatible = "rockchip,rk3399-emmc-phy" },
376 MODULE_DEVICE_TABLE(of, rockchip_emmc_phy_dt_ids);
378 static struct platform_driver rockchip_emmc_driver = {
379 .probe = rockchip_emmc_phy_probe,
381 .name = "rockchip-emmc-phy",
382 .of_match_table = rockchip_emmc_phy_dt_ids,
386 module_platform_driver(rockchip_emmc_driver);
388 MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
389 MODULE_DESCRIPTION("Rockchip EMMC PHY driver");
390 MODULE_LICENSE("GPL v2");