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10#include <linux/clk-provider.h>
11#include <linux/delay.h>
12#include <linux/module.h>
13#include <linux/i2c.h>
14#include <linux/regmap.h>
15#include <linux/slab.h>
16
17
18#define SI514_REG_LP 0
19#define SI514_REG_M_FRAC1 5
20#define SI514_REG_M_FRAC2 6
21#define SI514_REG_M_FRAC3 7
22#define SI514_REG_M_INT_FRAC 8
23#define SI514_REG_M_INT 9
24#define SI514_REG_HS_DIV 10
25#define SI514_REG_LS_HS_DIV 11
26#define SI514_REG_OE_STATE 14
27#define SI514_REG_RESET 128
28#define SI514_REG_CONTROL 132
29
30
31#define SI514_RESET_RST BIT(7)
32
33#define SI514_CONTROL_FCAL BIT(0)
34#define SI514_CONTROL_OE BIT(2)
35
36#define SI514_MIN_FREQ 100000U
37#define SI514_MAX_FREQ 250000000U
38
39#define FXO 31980000U
40
41#define FVCO_MIN 2080000000U
42#define FVCO_MAX 2500000000U
43
44#define HS_DIV_MAX 1022
45
46struct clk_si514 {
47 struct clk_hw hw;
48 struct regmap *regmap;
49 struct i2c_client *i2c_client;
50};
51#define to_clk_si514(_hw) container_of(_hw, struct clk_si514, hw)
52
53
54struct clk_si514_muldiv {
55 u32 m_frac;
56 u8 m_int;
57 u8 ls_div_bits;
58 u16 hs_div;
59};
60
61
62static int si514_enable_output(struct clk_si514 *data, bool enable)
63{
64 return regmap_update_bits(data->regmap, SI514_REG_CONTROL,
65 SI514_CONTROL_OE, enable ? SI514_CONTROL_OE : 0);
66}
67
68static int si514_prepare(struct clk_hw *hw)
69{
70 struct clk_si514 *data = to_clk_si514(hw);
71
72 return si514_enable_output(data, true);
73}
74
75static void si514_unprepare(struct clk_hw *hw)
76{
77 struct clk_si514 *data = to_clk_si514(hw);
78
79 si514_enable_output(data, false);
80}
81
82static int si514_is_prepared(struct clk_hw *hw)
83{
84 struct clk_si514 *data = to_clk_si514(hw);
85 unsigned int val;
86 int err;
87
88 err = regmap_read(data->regmap, SI514_REG_CONTROL, &val);
89 if (err < 0)
90 return err;
91
92 return !!(val & SI514_CONTROL_OE);
93}
94
95
96static int si514_get_muldiv(struct clk_si514 *data,
97 struct clk_si514_muldiv *settings)
98{
99 int err;
100 u8 reg[7];
101
102 err = regmap_bulk_read(data->regmap, SI514_REG_M_FRAC1,
103 reg, ARRAY_SIZE(reg));
104 if (err)
105 return err;
106
107 settings->m_frac = reg[0] | reg[1] << 8 | reg[2] << 16 |
108 (reg[3] & 0x1F) << 24;
109 settings->m_int = (reg[4] & 0x3f) << 3 | reg[3] >> 5;
110 settings->ls_div_bits = (reg[6] >> 4) & 0x07;
111 settings->hs_div = (reg[6] & 0x03) << 8 | reg[5];
112 return 0;
113}
114
115static int si514_set_muldiv(struct clk_si514 *data,
116 struct clk_si514_muldiv *settings)
117{
118 u8 lp;
119 u8 reg[7];
120 int err;
121
122
123
124 if (settings->m_int < 65 ||
125 (settings->m_int == 65 && settings->m_frac <= 139575831))
126 lp = 0x22;
127
128 else if (settings->m_int < 67 ||
129 (settings->m_int == 67 && settings->m_frac <= 461581994))
130 lp = 0x23;
131
132 else if (settings->m_int < 72 ||
133 (settings->m_int == 72 && settings->m_frac <= 503383578))
134 lp = 0x33;
135
136 else if (settings->m_int < 75 ||
137 (settings->m_int == 75 && settings->m_frac <= 452724474))
138 lp = 0x34;
139 else
140 lp = 0x44;
141
142 err = regmap_write(data->regmap, SI514_REG_LP, lp);
143 if (err < 0)
144 return err;
145
146 reg[0] = settings->m_frac;
147 reg[1] = settings->m_frac >> 8;
148 reg[2] = settings->m_frac >> 16;
149 reg[3] = settings->m_frac >> 24 | settings->m_int << 5;
150 reg[4] = settings->m_int >> 3;
151 reg[5] = settings->hs_div;
152 reg[6] = (settings->hs_div >> 8) | (settings->ls_div_bits << 4);
153
154 err = regmap_bulk_write(data->regmap, SI514_REG_HS_DIV, reg + 5, 2);
155 if (err < 0)
156 return err;
157
158
159
160
161 return regmap_bulk_write(data->regmap, SI514_REG_M_FRAC1, reg, 5);
162}
163
164
165static int si514_calc_muldiv(struct clk_si514_muldiv *settings,
166 unsigned long frequency)
167{
168 u64 m;
169 u32 ls_freq;
170 u32 tmp;
171 u8 res;
172
173 if ((frequency < SI514_MIN_FREQ) || (frequency > SI514_MAX_FREQ))
174 return -EINVAL;
175
176
177 ls_freq = frequency;
178 if (frequency >= (FVCO_MIN / HS_DIV_MAX))
179 settings->ls_div_bits = 0;
180 else {
181 res = 1;
182 tmp = 2 * HS_DIV_MAX;
183 while (tmp <= (HS_DIV_MAX * 32)) {
184 if ((frequency * tmp) >= FVCO_MIN)
185 break;
186 ++res;
187 tmp <<= 1;
188 }
189 settings->ls_div_bits = res;
190 ls_freq = frequency << res;
191 }
192
193
194 settings->hs_div = DIV_ROUND_UP(FVCO_MIN >> 1, ls_freq) << 1;
195
196
197 m = ((u64)(ls_freq * settings->hs_div) << 29) + (FXO / 2);
198 do_div(m, FXO);
199 settings->m_frac = (u32)m & (BIT(29) - 1);
200 settings->m_int = (u32)(m >> 29);
201
202 return 0;
203}
204
205
206static unsigned long si514_calc_rate(struct clk_si514_muldiv *settings)
207{
208 u64 m = settings->m_frac | ((u64)settings->m_int << 29);
209 u32 d = settings->hs_div * BIT(settings->ls_div_bits);
210
211 return ((u32)(((m * FXO) + (FXO / 2)) >> 29)) / d;
212}
213
214static unsigned long si514_recalc_rate(struct clk_hw *hw,
215 unsigned long parent_rate)
216{
217 struct clk_si514 *data = to_clk_si514(hw);
218 struct clk_si514_muldiv settings;
219 int err;
220
221 err = si514_get_muldiv(data, &settings);
222 if (err) {
223 dev_err(&data->i2c_client->dev, "unable to retrieve settings\n");
224 return 0;
225 }
226
227 return si514_calc_rate(&settings);
228}
229
230static long si514_round_rate(struct clk_hw *hw, unsigned long rate,
231 unsigned long *parent_rate)
232{
233 struct clk_si514_muldiv settings;
234 int err;
235
236 if (!rate)
237 return 0;
238
239 err = si514_calc_muldiv(&settings, rate);
240 if (err)
241 return err;
242
243 return si514_calc_rate(&settings);
244}
245
246
247
248
249
250
251static int si514_set_rate(struct clk_hw *hw, unsigned long rate,
252 unsigned long parent_rate)
253{
254 struct clk_si514 *data = to_clk_si514(hw);
255 struct clk_si514_muldiv settings;
256 unsigned int old_oe_state;
257 int err;
258
259 err = si514_calc_muldiv(&settings, rate);
260 if (err)
261 return err;
262
263 err = regmap_read(data->regmap, SI514_REG_CONTROL, &old_oe_state);
264 if (err)
265 return err;
266
267 si514_enable_output(data, false);
268
269 err = si514_set_muldiv(data, &settings);
270 if (err < 0)
271 return err;
272
273
274 err = regmap_write(data->regmap, SI514_REG_CONTROL, SI514_CONTROL_FCAL);
275 if (err < 0)
276 return err;
277
278
279 usleep_range(10000, 12000);
280
281 if (old_oe_state & SI514_CONTROL_OE)
282 si514_enable_output(data, true);
283
284 return err;
285}
286
287static const struct clk_ops si514_clk_ops = {
288 .prepare = si514_prepare,
289 .unprepare = si514_unprepare,
290 .is_prepared = si514_is_prepared,
291 .recalc_rate = si514_recalc_rate,
292 .round_rate = si514_round_rate,
293 .set_rate = si514_set_rate,
294};
295
296static bool si514_regmap_is_volatile(struct device *dev, unsigned int reg)
297{
298 switch (reg) {
299 case SI514_REG_CONTROL:
300 case SI514_REG_RESET:
301 return true;
302 default:
303 return false;
304 }
305}
306
307static bool si514_regmap_is_writeable(struct device *dev, unsigned int reg)
308{
309 switch (reg) {
310 case SI514_REG_LP:
311 case SI514_REG_M_FRAC1 ... SI514_REG_LS_HS_DIV:
312 case SI514_REG_OE_STATE:
313 case SI514_REG_RESET:
314 case SI514_REG_CONTROL:
315 return true;
316 default:
317 return false;
318 }
319}
320
321static const struct regmap_config si514_regmap_config = {
322 .reg_bits = 8,
323 .val_bits = 8,
324 .cache_type = REGCACHE_RBTREE,
325 .max_register = SI514_REG_CONTROL,
326 .writeable_reg = si514_regmap_is_writeable,
327 .volatile_reg = si514_regmap_is_volatile,
328};
329
330static int si514_probe(struct i2c_client *client,
331 const struct i2c_device_id *id)
332{
333 struct clk_si514 *data;
334 struct clk_init_data init;
335 int err;
336
337 data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
338 if (!data)
339 return -ENOMEM;
340
341 init.ops = &si514_clk_ops;
342 init.flags = 0;
343 init.num_parents = 0;
344 data->hw.init = &init;
345 data->i2c_client = client;
346
347 if (of_property_read_string(client->dev.of_node, "clock-output-names",
348 &init.name))
349 init.name = client->dev.of_node->name;
350
351 data->regmap = devm_regmap_init_i2c(client, &si514_regmap_config);
352 if (IS_ERR(data->regmap)) {
353 dev_err(&client->dev, "failed to allocate register map\n");
354 return PTR_ERR(data->regmap);
355 }
356
357 i2c_set_clientdata(client, data);
358
359 err = devm_clk_hw_register(&client->dev, &data->hw);
360 if (err) {
361 dev_err(&client->dev, "clock registration failed\n");
362 return err;
363 }
364 err = of_clk_add_hw_provider(client->dev.of_node, of_clk_hw_simple_get,
365 &data->hw);
366 if (err) {
367 dev_err(&client->dev, "unable to add clk provider\n");
368 return err;
369 }
370
371 return 0;
372}
373
374static int si514_remove(struct i2c_client *client)
375{
376 of_clk_del_provider(client->dev.of_node);
377 return 0;
378}
379
380static const struct i2c_device_id si514_id[] = {
381 { "si514", 0 },
382 { }
383};
384MODULE_DEVICE_TABLE(i2c, si514_id);
385
386static const struct of_device_id clk_si514_of_match[] = {
387 { .compatible = "silabs,si514" },
388 { },
389};
390MODULE_DEVICE_TABLE(of, clk_si514_of_match);
391
392static struct i2c_driver si514_driver = {
393 .driver = {
394 .name = "si514",
395 .of_match_table = clk_si514_of_match,
396 },
397 .probe = si514_probe,
398 .remove = si514_remove,
399 .id_table = si514_id,
400};
401module_i2c_driver(si514_driver);
402
403MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
404MODULE_DESCRIPTION("Si514 driver");
405MODULE_LICENSE("GPL");
406
