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6#include <linux/clk.h>
7#include <linux/i2c.h>
8#include <linux/interrupt.h>
9#include <linux/io.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12
13#define UNIPHIER_I2C_DTRM 0x00
14#define UNIPHIER_I2C_DTRM_IRQEN BIT(11)
15#define UNIPHIER_I2C_DTRM_STA BIT(10)
16#define UNIPHIER_I2C_DTRM_STO BIT(9)
17#define UNIPHIER_I2C_DTRM_NACK BIT(8)
18#define UNIPHIER_I2C_DTRM_RD BIT(0)
19#define UNIPHIER_I2C_DREC 0x04
20#define UNIPHIER_I2C_DREC_MST BIT(14)
21#define UNIPHIER_I2C_DREC_TX BIT(13)
22#define UNIPHIER_I2C_DREC_STS BIT(12)
23#define UNIPHIER_I2C_DREC_LRB BIT(11)
24#define UNIPHIER_I2C_DREC_LAB BIT(9)
25#define UNIPHIER_I2C_DREC_BBN BIT(8)
26#define UNIPHIER_I2C_MYAD 0x08
27#define UNIPHIER_I2C_CLK 0x0c
28#define UNIPHIER_I2C_BRST 0x10
29#define UNIPHIER_I2C_BRST_FOEN BIT(1)
30#define UNIPHIER_I2C_BRST_RSCL BIT(0)
31#define UNIPHIER_I2C_HOLD 0x14
32#define UNIPHIER_I2C_BSTS 0x18
33#define UNIPHIER_I2C_BSTS_SDA BIT(1)
34#define UNIPHIER_I2C_BSTS_SCL BIT(0)
35#define UNIPHIER_I2C_NOISE 0x1c
36#define UNIPHIER_I2C_SETUP 0x20
37
38struct uniphier_i2c_priv {
39 struct completion comp;
40 struct i2c_adapter adap;
41 void __iomem *membase;
42 struct clk *clk;
43 unsigned int busy_cnt;
44 unsigned int clk_cycle;
45};
46
47static irqreturn_t uniphier_i2c_interrupt(int irq, void *dev_id)
48{
49 struct uniphier_i2c_priv *priv = dev_id;
50
51
52
53
54
55
56 complete(&priv->comp);
57
58 return IRQ_HANDLED;
59}
60
61static int uniphier_i2c_xfer_byte(struct i2c_adapter *adap, u32 txdata,
62 u32 *rxdatap)
63{
64 struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap);
65 unsigned long time_left;
66 u32 rxdata;
67
68 reinit_completion(&priv->comp);
69
70 txdata |= UNIPHIER_I2C_DTRM_IRQEN;
71 writel(txdata, priv->membase + UNIPHIER_I2C_DTRM);
72
73 time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
74 if (unlikely(!time_left)) {
75 dev_err(&adap->dev, "transaction timeout\n");
76 return -ETIMEDOUT;
77 }
78
79 rxdata = readl(priv->membase + UNIPHIER_I2C_DREC);
80 if (rxdatap)
81 *rxdatap = rxdata;
82
83 return 0;
84}
85
86static int uniphier_i2c_send_byte(struct i2c_adapter *adap, u32 txdata)
87{
88 u32 rxdata;
89 int ret;
90
91 ret = uniphier_i2c_xfer_byte(adap, txdata, &rxdata);
92 if (ret)
93 return ret;
94
95 if (unlikely(rxdata & UNIPHIER_I2C_DREC_LAB))
96 return -EAGAIN;
97
98 if (unlikely(rxdata & UNIPHIER_I2C_DREC_LRB))
99 return -ENXIO;
100
101 return 0;
102}
103
104static int uniphier_i2c_tx(struct i2c_adapter *adap, u16 addr, u16 len,
105 const u8 *buf)
106{
107 int ret;
108
109 ret = uniphier_i2c_send_byte(adap, addr << 1 |
110 UNIPHIER_I2C_DTRM_STA |
111 UNIPHIER_I2C_DTRM_NACK);
112 if (ret)
113 return ret;
114
115 while (len--) {
116 ret = uniphier_i2c_send_byte(adap,
117 UNIPHIER_I2C_DTRM_NACK | *buf++);
118 if (ret)
119 return ret;
120 }
121
122 return 0;
123}
124
125static int uniphier_i2c_rx(struct i2c_adapter *adap, u16 addr, u16 len,
126 u8 *buf)
127{
128 int ret;
129
130 ret = uniphier_i2c_send_byte(adap, addr << 1 |
131 UNIPHIER_I2C_DTRM_STA |
132 UNIPHIER_I2C_DTRM_NACK |
133 UNIPHIER_I2C_DTRM_RD);
134 if (ret)
135 return ret;
136
137 while (len--) {
138 u32 rxdata;
139
140 ret = uniphier_i2c_xfer_byte(adap,
141 len ? 0 : UNIPHIER_I2C_DTRM_NACK,
142 &rxdata);
143 if (ret)
144 return ret;
145 *buf++ = rxdata;
146 }
147
148 return 0;
149}
150
151static int uniphier_i2c_stop(struct i2c_adapter *adap)
152{
153 return uniphier_i2c_send_byte(adap, UNIPHIER_I2C_DTRM_STO |
154 UNIPHIER_I2C_DTRM_NACK);
155}
156
157static int uniphier_i2c_master_xfer_one(struct i2c_adapter *adap,
158 struct i2c_msg *msg, bool stop)
159{
160 bool is_read = msg->flags & I2C_M_RD;
161 bool recovery = false;
162 int ret;
163
164 if (is_read)
165 ret = uniphier_i2c_rx(adap, msg->addr, msg->len, msg->buf);
166 else
167 ret = uniphier_i2c_tx(adap, msg->addr, msg->len, msg->buf);
168
169 if (ret == -EAGAIN)
170 return ret;
171
172 if (ret == -ETIMEDOUT) {
173
174 stop = false;
175 recovery = true;
176 }
177
178 if (stop) {
179 int ret2 = uniphier_i2c_stop(adap);
180
181 if (ret2) {
182
183 recovery = true;
184 ret = ret ?: ret2;
185 }
186 }
187
188 if (recovery)
189 i2c_recover_bus(adap);
190
191 return ret;
192}
193
194static int uniphier_i2c_check_bus_busy(struct i2c_adapter *adap)
195{
196 struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap);
197
198 if (!(readl(priv->membase + UNIPHIER_I2C_DREC) &
199 UNIPHIER_I2C_DREC_BBN)) {
200 if (priv->busy_cnt++ > 3) {
201
202
203
204
205 i2c_recover_bus(adap);
206 priv->busy_cnt = 0;
207 }
208
209 return -EAGAIN;
210 }
211
212 priv->busy_cnt = 0;
213 return 0;
214}
215
216static int uniphier_i2c_master_xfer(struct i2c_adapter *adap,
217 struct i2c_msg *msgs, int num)
218{
219 struct i2c_msg *msg, *emsg = msgs + num;
220 int ret;
221
222 ret = uniphier_i2c_check_bus_busy(adap);
223 if (ret)
224 return ret;
225
226 for (msg = msgs; msg < emsg; msg++) {
227
228 bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
229
230 ret = uniphier_i2c_master_xfer_one(adap, msg, stop);
231 if (ret)
232 return ret;
233 }
234
235 return num;
236}
237
238static u32 uniphier_i2c_functionality(struct i2c_adapter *adap)
239{
240 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
241}
242
243static const struct i2c_algorithm uniphier_i2c_algo = {
244 .master_xfer = uniphier_i2c_master_xfer,
245 .functionality = uniphier_i2c_functionality,
246};
247
248static void uniphier_i2c_reset(struct uniphier_i2c_priv *priv, bool reset_on)
249{
250 u32 val = UNIPHIER_I2C_BRST_RSCL;
251
252 val |= reset_on ? 0 : UNIPHIER_I2C_BRST_FOEN;
253 writel(val, priv->membase + UNIPHIER_I2C_BRST);
254}
255
256static int uniphier_i2c_get_scl(struct i2c_adapter *adap)
257{
258 struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap);
259
260 return !!(readl(priv->membase + UNIPHIER_I2C_BSTS) &
261 UNIPHIER_I2C_BSTS_SCL);
262}
263
264static void uniphier_i2c_set_scl(struct i2c_adapter *adap, int val)
265{
266 struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap);
267
268 writel(val ? UNIPHIER_I2C_BRST_RSCL : 0,
269 priv->membase + UNIPHIER_I2C_BRST);
270}
271
272static int uniphier_i2c_get_sda(struct i2c_adapter *adap)
273{
274 struct uniphier_i2c_priv *priv = i2c_get_adapdata(adap);
275
276 return !!(readl(priv->membase + UNIPHIER_I2C_BSTS) &
277 UNIPHIER_I2C_BSTS_SDA);
278}
279
280static void uniphier_i2c_unprepare_recovery(struct i2c_adapter *adap)
281{
282 uniphier_i2c_reset(i2c_get_adapdata(adap), false);
283}
284
285static struct i2c_bus_recovery_info uniphier_i2c_bus_recovery_info = {
286 .recover_bus = i2c_generic_scl_recovery,
287 .get_scl = uniphier_i2c_get_scl,
288 .set_scl = uniphier_i2c_set_scl,
289 .get_sda = uniphier_i2c_get_sda,
290 .unprepare_recovery = uniphier_i2c_unprepare_recovery,
291};
292
293static void uniphier_i2c_hw_init(struct uniphier_i2c_priv *priv)
294{
295 unsigned int cyc = priv->clk_cycle;
296
297 uniphier_i2c_reset(priv, true);
298
299
300
301
302
303
304
305 writel((cyc * 5 / 9 << 16) | cyc, priv->membase + UNIPHIER_I2C_CLK);
306
307 uniphier_i2c_reset(priv, false);
308}
309
310static int uniphier_i2c_probe(struct platform_device *pdev)
311{
312 struct device *dev = &pdev->dev;
313 struct uniphier_i2c_priv *priv;
314 u32 bus_speed;
315 unsigned long clk_rate;
316 int irq, ret;
317
318 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
319 if (!priv)
320 return -ENOMEM;
321
322 priv->membase = devm_platform_ioremap_resource(pdev, 0);
323 if (IS_ERR(priv->membase))
324 return PTR_ERR(priv->membase);
325
326 irq = platform_get_irq(pdev, 0);
327 if (irq < 0)
328 return irq;
329
330 if (of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed))
331 bus_speed = I2C_MAX_STANDARD_MODE_FREQ;
332
333 if (!bus_speed || bus_speed > I2C_MAX_FAST_MODE_FREQ) {
334 dev_err(dev, "invalid clock-frequency %d\n", bus_speed);
335 return -EINVAL;
336 }
337
338 priv->clk = devm_clk_get(dev, NULL);
339 if (IS_ERR(priv->clk)) {
340 dev_err(dev, "failed to get clock\n");
341 return PTR_ERR(priv->clk);
342 }
343
344 ret = clk_prepare_enable(priv->clk);
345 if (ret)
346 return ret;
347
348 clk_rate = clk_get_rate(priv->clk);
349 if (!clk_rate) {
350 dev_err(dev, "input clock rate should not be zero\n");
351 ret = -EINVAL;
352 goto disable_clk;
353 }
354
355 priv->clk_cycle = clk_rate / bus_speed;
356 init_completion(&priv->comp);
357 priv->adap.owner = THIS_MODULE;
358 priv->adap.algo = &uniphier_i2c_algo;
359 priv->adap.dev.parent = dev;
360 priv->adap.dev.of_node = dev->of_node;
361 strlcpy(priv->adap.name, "UniPhier I2C", sizeof(priv->adap.name));
362 priv->adap.bus_recovery_info = &uniphier_i2c_bus_recovery_info;
363 i2c_set_adapdata(&priv->adap, priv);
364 platform_set_drvdata(pdev, priv);
365
366 uniphier_i2c_hw_init(priv);
367
368 ret = devm_request_irq(dev, irq, uniphier_i2c_interrupt, 0, pdev->name,
369 priv);
370 if (ret) {
371 dev_err(dev, "failed to request irq %d\n", irq);
372 goto disable_clk;
373 }
374
375 ret = i2c_add_adapter(&priv->adap);
376disable_clk:
377 if (ret)
378 clk_disable_unprepare(priv->clk);
379
380 return ret;
381}
382
383static int uniphier_i2c_remove(struct platform_device *pdev)
384{
385 struct uniphier_i2c_priv *priv = platform_get_drvdata(pdev);
386
387 i2c_del_adapter(&priv->adap);
388 clk_disable_unprepare(priv->clk);
389
390 return 0;
391}
392
393static int __maybe_unused uniphier_i2c_suspend(struct device *dev)
394{
395 struct uniphier_i2c_priv *priv = dev_get_drvdata(dev);
396
397 clk_disable_unprepare(priv->clk);
398
399 return 0;
400}
401
402static int __maybe_unused uniphier_i2c_resume(struct device *dev)
403{
404 struct uniphier_i2c_priv *priv = dev_get_drvdata(dev);
405 int ret;
406
407 ret = clk_prepare_enable(priv->clk);
408 if (ret)
409 return ret;
410
411 uniphier_i2c_hw_init(priv);
412
413 return 0;
414}
415
416static const struct dev_pm_ops uniphier_i2c_pm_ops = {
417 SET_SYSTEM_SLEEP_PM_OPS(uniphier_i2c_suspend, uniphier_i2c_resume)
418};
419
420static const struct of_device_id uniphier_i2c_match[] = {
421 { .compatible = "socionext,uniphier-i2c" },
422 { }
423};
424MODULE_DEVICE_TABLE(of, uniphier_i2c_match);
425
426static struct platform_driver uniphier_i2c_drv = {
427 .probe = uniphier_i2c_probe,
428 .remove = uniphier_i2c_remove,
429 .driver = {
430 .name = "uniphier-i2c",
431 .of_match_table = uniphier_i2c_match,
432 .pm = &uniphier_i2c_pm_ops,
433 },
434};
435module_platform_driver(uniphier_i2c_drv);
436
437MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
438MODULE_DESCRIPTION("UniPhier I2C bus driver");
439MODULE_LICENSE("GPL");
440
