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edc12763 MV |
1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* | |
3 | * Driver for Skyworks Si521xx PCIe clock generator driver | |
4 | * | |
5 | * The following series can be supported: | |
6 | * - Si52144 - 4x DIFF | |
7 | * - Si52146 - 6x DIFF | |
8 | * - Si52147 - 9x DIFF | |
9 | * Currently tested: | |
10 | * - Si52144 | |
11 | * | |
12 | * Copyright (C) 2022 Marek Vasut <marex@denx.de> | |
13 | */ | |
14 | ||
15 | #include <linux/bitfield.h> | |
16 | #include <linux/bitrev.h> | |
17 | #include <linux/clk-provider.h> | |
18 | #include <linux/i2c.h> | |
19 | #include <linux/mod_devicetable.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/of.h> | |
22 | #include <linux/regmap.h> | |
23 | ||
24 | /* OE1 and OE2 register */ | |
25 | #define SI521XX_REG_OE(n) (((n) & 0x1) + 1) | |
26 | #define SI521XX_REG_ID 0x3 | |
27 | #define SI521XX_REG_ID_PROG GENMASK(7, 4) | |
28 | #define SI521XX_REG_ID_VENDOR GENMASK(3, 0) | |
29 | #define SI521XX_REG_BC 0x4 | |
30 | #define SI521XX_REG_DA 0x5 | |
31 | #define SI521XX_REG_DA_AMP_SEL BIT(7) | |
32 | #define SI521XX_REG_DA_AMP_MASK GENMASK(6, 4) | |
33 | #define SI521XX_REG_DA_AMP_MIN 300000 | |
34 | #define SI521XX_REG_DA_AMP_DEFAULT 800000 | |
35 | #define SI521XX_REG_DA_AMP_MAX 1000000 | |
36 | #define SI521XX_REG_DA_AMP_STEP 100000 | |
37 | #define SI521XX_REG_DA_AMP(UV) \ | |
38 | FIELD_PREP(SI521XX_REG_DA_AMP_MASK, \ | |
39 | ((UV) - SI521XX_REG_DA_AMP_MIN) / SI521XX_REG_DA_AMP_STEP) | |
40 | #define SI521XX_REG_DA_UNKNOWN BIT(3) /* Always set */ | |
41 | ||
42 | /* Count of populated OE bits in control register ref, 1 and 2 */ | |
43 | #define SI521XX_OE_MAP(cr1, cr2) (((cr2) << 8) | (cr1)) | |
44 | #define SI521XX_OE_MAP_GET_OE(oe, map) (((map) >> (((oe) - 1) * 8)) & 0xff) | |
45 | ||
46 | #define SI521XX_DIFF_MULT 4 | |
47 | #define SI521XX_DIFF_DIV 1 | |
48 | ||
49 | /* Supported Skyworks Si521xx models. */ | |
50 | enum si521xx_model { | |
51 | SI52144 = 0x44, | |
52 | SI52146 = 0x46, | |
53 | SI52147 = 0x47, | |
54 | }; | |
55 | ||
56 | struct si521xx; | |
57 | ||
58 | struct si_clk { | |
59 | struct clk_hw hw; | |
60 | struct si521xx *si; | |
61 | u8 reg; | |
62 | u8 bit; | |
63 | }; | |
64 | ||
65 | struct si521xx { | |
66 | struct i2c_client *client; | |
67 | struct regmap *regmap; | |
68 | struct si_clk clk_dif[9]; | |
69 | u16 chip_info; | |
70 | u8 pll_amplitude; | |
71 | }; | |
72 | ||
73 | /* | |
74 | * Si521xx i2c regmap | |
75 | */ | |
76 | static const struct regmap_range si521xx_readable_ranges[] = { | |
77 | regmap_reg_range(SI521XX_REG_OE(0), SI521XX_REG_DA), | |
78 | }; | |
79 | ||
80 | static const struct regmap_access_table si521xx_readable_table = { | |
81 | .yes_ranges = si521xx_readable_ranges, | |
82 | .n_yes_ranges = ARRAY_SIZE(si521xx_readable_ranges), | |
83 | }; | |
84 | ||
85 | static const struct regmap_range si521xx_writeable_ranges[] = { | |
86 | regmap_reg_range(SI521XX_REG_OE(0), SI521XX_REG_OE(1)), | |
87 | regmap_reg_range(SI521XX_REG_BC, SI521XX_REG_DA), | |
88 | }; | |
89 | ||
90 | static const struct regmap_access_table si521xx_writeable_table = { | |
91 | .yes_ranges = si521xx_writeable_ranges, | |
92 | .n_yes_ranges = ARRAY_SIZE(si521xx_writeable_ranges), | |
93 | }; | |
94 | ||
95 | static int si521xx_regmap_i2c_write(void *context, unsigned int reg, | |
96 | unsigned int val) | |
97 | { | |
98 | struct i2c_client *i2c = context; | |
99 | const u8 data[3] = { reg, 1, val }; | |
100 | const int count = ARRAY_SIZE(data); | |
101 | int ret; | |
102 | ||
103 | ret = i2c_master_send(i2c, data, count); | |
104 | if (ret == count) | |
105 | return 0; | |
106 | else if (ret < 0) | |
107 | return ret; | |
108 | else | |
109 | return -EIO; | |
110 | } | |
111 | ||
112 | static int si521xx_regmap_i2c_read(void *context, unsigned int reg, | |
113 | unsigned int *val) | |
114 | { | |
115 | struct i2c_client *i2c = context; | |
116 | struct i2c_msg xfer[2]; | |
117 | u8 txdata = reg; | |
118 | u8 rxdata[2]; | |
119 | int ret; | |
120 | ||
121 | xfer[0].addr = i2c->addr; | |
122 | xfer[0].flags = 0; | |
123 | xfer[0].len = 1; | |
124 | xfer[0].buf = (void *)&txdata; | |
125 | ||
126 | xfer[1].addr = i2c->addr; | |
127 | xfer[1].flags = I2C_M_RD; | |
128 | xfer[1].len = 2; | |
129 | xfer[1].buf = (void *)rxdata; | |
130 | ||
131 | ret = i2c_transfer(i2c->adapter, xfer, 2); | |
132 | if (ret < 0) | |
133 | return ret; | |
134 | if (ret != 2) | |
135 | return -EIO; | |
136 | ||
137 | /* | |
138 | * Byte 0 is transfer length, which is always 1 due | |
139 | * to BCP register programming to 1 in si521xx_probe(), | |
140 | * ignore it and use data from Byte 1. | |
141 | */ | |
142 | *val = rxdata[1]; | |
143 | return 0; | |
144 | } | |
145 | ||
146 | static const struct regmap_config si521xx_regmap_config = { | |
147 | .reg_bits = 8, | |
148 | .val_bits = 8, | |
149 | .cache_type = REGCACHE_NONE, | |
150 | .max_register = SI521XX_REG_DA, | |
151 | .rd_table = &si521xx_readable_table, | |
152 | .wr_table = &si521xx_writeable_table, | |
153 | .reg_write = si521xx_regmap_i2c_write, | |
154 | .reg_read = si521xx_regmap_i2c_read, | |
155 | }; | |
156 | ||
157 | static unsigned long si521xx_diff_recalc_rate(struct clk_hw *hw, | |
158 | unsigned long parent_rate) | |
159 | { | |
160 | unsigned long long rate; | |
161 | ||
162 | rate = (unsigned long long)parent_rate * SI521XX_DIFF_MULT; | |
163 | do_div(rate, SI521XX_DIFF_DIV); | |
164 | return (unsigned long)rate; | |
165 | } | |
166 | ||
167 | static long si521xx_diff_round_rate(struct clk_hw *hw, unsigned long rate, | |
168 | unsigned long *prate) | |
169 | { | |
170 | unsigned long best_parent; | |
171 | ||
172 | best_parent = (rate / SI521XX_DIFF_MULT) * SI521XX_DIFF_DIV; | |
173 | *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent); | |
174 | ||
175 | return (*prate / SI521XX_DIFF_DIV) * SI521XX_DIFF_MULT; | |
176 | } | |
177 | ||
178 | static int si521xx_diff_set_rate(struct clk_hw *hw, unsigned long rate, | |
179 | unsigned long parent_rate) | |
180 | { | |
181 | /* | |
182 | * We must report success but we can do so unconditionally because | |
183 | * si521xx_diff_round_rate returns values that ensure this call is a | |
184 | * nop. | |
185 | */ | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | #define to_si521xx_clk(_hw) container_of(_hw, struct si_clk, hw) | |
191 | ||
192 | static int si521xx_diff_prepare(struct clk_hw *hw) | |
193 | { | |
194 | struct si_clk *si_clk = to_si521xx_clk(hw); | |
195 | struct si521xx *si = si_clk->si; | |
196 | ||
197 | regmap_set_bits(si->regmap, SI521XX_REG_OE(si_clk->reg), si_clk->bit); | |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
202 | static void si521xx_diff_unprepare(struct clk_hw *hw) | |
203 | { | |
204 | struct si_clk *si_clk = to_si521xx_clk(hw); | |
205 | struct si521xx *si = si_clk->si; | |
206 | ||
207 | regmap_clear_bits(si->regmap, SI521XX_REG_OE(si_clk->reg), si_clk->bit); | |
208 | } | |
209 | ||
210 | static const struct clk_ops si521xx_diff_clk_ops = { | |
211 | .round_rate = si521xx_diff_round_rate, | |
212 | .set_rate = si521xx_diff_set_rate, | |
213 | .recalc_rate = si521xx_diff_recalc_rate, | |
214 | .prepare = si521xx_diff_prepare, | |
215 | .unprepare = si521xx_diff_unprepare, | |
216 | }; | |
217 | ||
218 | static int si521xx_get_common_config(struct si521xx *si) | |
219 | { | |
220 | struct i2c_client *client = si->client; | |
221 | struct device_node *np = client->dev.of_node; | |
222 | unsigned int amp; | |
223 | int ret; | |
224 | ||
225 | /* Set defaults */ | |
226 | si->pll_amplitude = SI521XX_REG_DA_AMP(SI521XX_REG_DA_AMP_DEFAULT); | |
227 | ||
228 | /* Output clock amplitude */ | |
229 | ret = of_property_read_u32(np, "skyworks,out-amplitude-microvolt", | |
230 | &); | |
231 | if (!ret) { | |
232 | if (amp < SI521XX_REG_DA_AMP_MIN || amp > SI521XX_REG_DA_AMP_MAX || | |
233 | amp % SI521XX_REG_DA_AMP_STEP) { | |
234 | return dev_err_probe(&client->dev, -EINVAL, | |
235 | "Invalid skyworks,out-amplitude-microvolt value\n"); | |
236 | } | |
237 | si->pll_amplitude = SI521XX_REG_DA_AMP(amp); | |
238 | } | |
239 | ||
240 | return 0; | |
241 | } | |
242 | ||
243 | static void si521xx_update_config(struct si521xx *si) | |
244 | { | |
245 | /* If amplitude is non-default, update it. */ | |
246 | if (si->pll_amplitude == SI521XX_REG_DA_AMP(SI521XX_REG_DA_AMP_DEFAULT)) | |
247 | return; | |
248 | ||
249 | regmap_update_bits(si->regmap, SI521XX_REG_DA, | |
250 | SI521XX_REG_DA_AMP_MASK, si->pll_amplitude); | |
251 | } | |
252 | ||
253 | static void si521xx_diff_idx_to_reg_bit(const u16 chip_info, const int idx, | |
254 | struct si_clk *clk) | |
255 | { | |
256 | unsigned long mask; | |
257 | int oe, b, ctr = 0; | |
258 | ||
259 | for (oe = 1; oe <= 2; oe++) { | |
260 | mask = bitrev8(SI521XX_OE_MAP_GET_OE(oe, chip_info)); | |
261 | for_each_set_bit(b, &mask, 8) { | |
262 | if (ctr++ != idx) | |
263 | continue; | |
264 | clk->reg = SI521XX_REG_OE(oe); | |
265 | clk->bit = 7 - b; | |
266 | return; | |
267 | } | |
268 | } | |
269 | } | |
270 | ||
271 | static struct clk_hw * | |
272 | si521xx_of_clk_get(struct of_phandle_args *clkspec, void *data) | |
273 | { | |
274 | struct si521xx *si = data; | |
275 | unsigned int idx = clkspec->args[0]; | |
276 | ||
277 | return &si->clk_dif[idx].hw; | |
278 | } | |
279 | ||
280 | static int si521xx_probe(struct i2c_client *client) | |
281 | { | |
282 | const u16 chip_info = (u16)(uintptr_t)device_get_match_data(&client->dev); | |
283 | const struct clk_parent_data clk_parent_data = { .index = 0 }; | |
284 | struct si521xx *si; | |
285 | unsigned char name[6] = "DIFF0"; | |
286 | struct clk_init_data init = {}; | |
287 | int i, ret; | |
288 | ||
289 | if (!chip_info) | |
290 | return -EINVAL; | |
291 | ||
292 | si = devm_kzalloc(&client->dev, sizeof(*si), GFP_KERNEL); | |
293 | if (!si) | |
294 | return -ENOMEM; | |
295 | ||
296 | i2c_set_clientdata(client, si); | |
297 | si->client = client; | |
298 | ||
299 | /* Fetch common configuration from DT (if specified) */ | |
300 | ret = si521xx_get_common_config(si); | |
301 | if (ret) | |
302 | return ret; | |
303 | ||
304 | si->regmap = devm_regmap_init(&client->dev, NULL, client, | |
305 | &si521xx_regmap_config); | |
306 | if (IS_ERR(si->regmap)) | |
307 | return dev_err_probe(&client->dev, PTR_ERR(si->regmap), | |
308 | "Failed to allocate register map\n"); | |
309 | ||
310 | /* Always read back 1 Byte via I2C */ | |
311 | ret = regmap_write(si->regmap, SI521XX_REG_BC, 1); | |
312 | if (ret < 0) | |
313 | return ret; | |
314 | ||
315 | /* Register clock */ | |
316 | for (i = 0; i < hweight16(chip_info); i++) { | |
317 | memset(&init, 0, sizeof(init)); | |
318 | snprintf(name, 6, "DIFF%d", i); | |
319 | init.name = name; | |
320 | init.ops = &si521xx_diff_clk_ops; | |
321 | init.parent_data = &clk_parent_data; | |
322 | init.num_parents = 1; | |
323 | init.flags = CLK_SET_RATE_PARENT; | |
324 | ||
325 | si->clk_dif[i].hw.init = &init; | |
326 | si->clk_dif[i].si = si; | |
327 | ||
328 | si521xx_diff_idx_to_reg_bit(chip_info, i, &si->clk_dif[i]); | |
329 | ||
330 | ret = devm_clk_hw_register(&client->dev, &si->clk_dif[i].hw); | |
331 | if (ret) | |
332 | return ret; | |
333 | } | |
334 | ||
335 | ret = devm_of_clk_add_hw_provider(&client->dev, si521xx_of_clk_get, si); | |
336 | if (!ret) | |
337 | si521xx_update_config(si); | |
338 | ||
339 | return ret; | |
340 | } | |
341 | ||
342 | static int __maybe_unused si521xx_suspend(struct device *dev) | |
343 | { | |
344 | struct si521xx *si = dev_get_drvdata(dev); | |
345 | ||
346 | regcache_cache_only(si->regmap, true); | |
347 | regcache_mark_dirty(si->regmap); | |
348 | ||
349 | return 0; | |
350 | } | |
351 | ||
352 | static int __maybe_unused si521xx_resume(struct device *dev) | |
353 | { | |
354 | struct si521xx *si = dev_get_drvdata(dev); | |
355 | int ret; | |
356 | ||
357 | regcache_cache_only(si->regmap, false); | |
358 | ret = regcache_sync(si->regmap); | |
359 | if (ret) | |
360 | dev_err(dev, "Failed to restore register map: %d\n", ret); | |
361 | return ret; | |
362 | } | |
363 | ||
364 | static const struct i2c_device_id si521xx_id[] = { | |
365 | { "si52144", .driver_data = SI521XX_OE_MAP(0x5, 0xc0) }, | |
366 | { "si52146", .driver_data = SI521XX_OE_MAP(0x15, 0xe0) }, | |
367 | { "si52147", .driver_data = SI521XX_OE_MAP(0x17, 0xf8) }, | |
368 | { } | |
369 | }; | |
370 | MODULE_DEVICE_TABLE(i2c, si521xx_id); | |
371 | ||
372 | static const struct of_device_id clk_si521xx_of_match[] = { | |
373 | { .compatible = "skyworks,si52144", .data = (void *)SI521XX_OE_MAP(0x5, 0xc0) }, | |
374 | { .compatible = "skyworks,si52146", .data = (void *)SI521XX_OE_MAP(0x15, 0xe0) }, | |
375 | { .compatible = "skyworks,si52147", .data = (void *)SI521XX_OE_MAP(0x15, 0xf8) }, | |
376 | { } | |
377 | }; | |
378 | MODULE_DEVICE_TABLE(of, clk_si521xx_of_match); | |
379 | ||
380 | static SIMPLE_DEV_PM_OPS(si521xx_pm_ops, si521xx_suspend, si521xx_resume); | |
381 | ||
382 | static struct i2c_driver si521xx_driver = { | |
383 | .driver = { | |
384 | .name = "clk-si521xx", | |
385 | .pm = &si521xx_pm_ops, | |
386 | .of_match_table = clk_si521xx_of_match, | |
387 | }, | |
388 | .probe_new = si521xx_probe, | |
389 | .id_table = si521xx_id, | |
390 | }; | |
391 | module_i2c_driver(si521xx_driver); | |
392 | ||
393 | MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); | |
394 | MODULE_DESCRIPTION("Skyworks Si521xx PCIe clock generator driver"); | |
395 | MODULE_LICENSE("GPL"); |