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19#include <linux/module.h>
20#include <linux/platform_device.h>
21#include <linux/i2c.h>
22#include <linux/delay.h>
23#include <linux/mfd/kempld.h>
24
25#define KEMPLD_I2C_PRELOW 0x0b
26#define KEMPLD_I2C_PREHIGH 0x0c
27#define KEMPLD_I2C_DATA 0x0e
28
29#define KEMPLD_I2C_CTRL 0x0d
30#define I2C_CTRL_IEN 0x40
31#define I2C_CTRL_EN 0x80
32
33#define KEMPLD_I2C_STAT 0x0f
34#define I2C_STAT_IF 0x01
35#define I2C_STAT_TIP 0x02
36#define I2C_STAT_ARBLOST 0x20
37#define I2C_STAT_BUSY 0x40
38#define I2C_STAT_NACK 0x80
39
40#define KEMPLD_I2C_CMD 0x0f
41#define I2C_CMD_START 0x91
42#define I2C_CMD_STOP 0x41
43#define I2C_CMD_READ 0x21
44#define I2C_CMD_WRITE 0x11
45#define I2C_CMD_READ_ACK 0x21
46#define I2C_CMD_READ_NACK 0x29
47#define I2C_CMD_IACK 0x01
48
49#define KEMPLD_I2C_FREQ_MAX 2700
50#define KEMPLD_I2C_FREQ_STD 100
51
52enum {
53 STATE_DONE = 0,
54 STATE_INIT,
55 STATE_ADDR,
56 STATE_ADDR10,
57 STATE_START,
58 STATE_WRITE,
59 STATE_READ,
60 STATE_ERROR,
61};
62
63struct kempld_i2c_data {
64 struct device *dev;
65 struct kempld_device_data *pld;
66 struct i2c_adapter adap;
67 struct i2c_msg *msg;
68 int pos;
69 int nmsgs;
70 int state;
71 bool was_active;
72};
73
74static unsigned int bus_frequency = KEMPLD_I2C_FREQ_STD;
75module_param(bus_frequency, uint, 0);
76MODULE_PARM_DESC(bus_frequency, "Set I2C bus frequency in kHz (default="
77 __MODULE_STRING(KEMPLD_I2C_FREQ_STD)")");
78
79static int i2c_bus = -1;
80module_param(i2c_bus, int, 0);
81MODULE_PARM_DESC(i2c_bus, "Set I2C bus number (default=-1 for dynamic assignment)");
82
83static bool i2c_gpio_mux;
84module_param(i2c_gpio_mux, bool, 0);
85MODULE_PARM_DESC(i2c_gpio_mux, "Enable I2C port on GPIO out (default=false)");
86
87
88
89
90static int kempld_i2c_process(struct kempld_i2c_data *i2c)
91{
92 struct kempld_device_data *pld = i2c->pld;
93 u8 stat = kempld_read8(pld, KEMPLD_I2C_STAT);
94 struct i2c_msg *msg = i2c->msg;
95 u8 addr;
96
97
98 if (stat & I2C_STAT_TIP)
99 return -EBUSY;
100
101 if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {
102
103 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_IACK);
104 if (i2c->state == STATE_ERROR)
105 return -EIO;
106 return 0;
107 }
108
109
110 if (stat & I2C_STAT_ARBLOST) {
111 i2c->state = STATE_ERROR;
112 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
113 return -EAGAIN;
114 }
115
116 if (i2c->state == STATE_INIT) {
117 if (stat & I2C_STAT_BUSY)
118 return -EBUSY;
119
120 i2c->state = STATE_ADDR;
121 }
122
123 if (i2c->state == STATE_ADDR) {
124
125 if (i2c->msg->flags & I2C_M_TEN) {
126 addr = 0xf0 | ((i2c->msg->addr >> 7) & 0x6);
127 i2c->state = STATE_ADDR10;
128 } else {
129 addr = (i2c->msg->addr << 1);
130 i2c->state = STATE_START;
131 }
132
133
134 addr |= (i2c->msg->flags & I2C_M_RD) ? 1 : 0;
135
136 kempld_write8(pld, KEMPLD_I2C_DATA, addr);
137 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_START);
138
139 return 0;
140 }
141
142
143 if (i2c->state == STATE_ADDR10) {
144 kempld_write8(pld, KEMPLD_I2C_DATA, i2c->msg->addr & 0xff);
145 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_WRITE);
146
147 i2c->state = STATE_START;
148 return 0;
149 }
150
151 if (i2c->state == STATE_START || i2c->state == STATE_WRITE) {
152 i2c->state = (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
153
154 if (stat & I2C_STAT_NACK) {
155 i2c->state = STATE_ERROR;
156 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
157 return -ENXIO;
158 }
159 } else {
160 msg->buf[i2c->pos++] = kempld_read8(pld, KEMPLD_I2C_DATA);
161 }
162
163 if (i2c->pos >= msg->len) {
164 i2c->nmsgs--;
165 i2c->msg++;
166 i2c->pos = 0;
167 msg = i2c->msg;
168
169 if (i2c->nmsgs) {
170 if (!(msg->flags & I2C_M_NOSTART)) {
171 i2c->state = STATE_ADDR;
172 return 0;
173 } else {
174 i2c->state = (msg->flags & I2C_M_RD)
175 ? STATE_READ : STATE_WRITE;
176 }
177 } else {
178 i2c->state = STATE_DONE;
179 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
180 return 0;
181 }
182 }
183
184 if (i2c->state == STATE_READ) {
185 kempld_write8(pld, KEMPLD_I2C_CMD, i2c->pos == (msg->len - 1) ?
186 I2C_CMD_READ_NACK : I2C_CMD_READ_ACK);
187 } else {
188 kempld_write8(pld, KEMPLD_I2C_DATA, msg->buf[i2c->pos++]);
189 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_WRITE);
190 }
191
192 return 0;
193}
194
195static int kempld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
196 int num)
197{
198 struct kempld_i2c_data *i2c = i2c_get_adapdata(adap);
199 struct kempld_device_data *pld = i2c->pld;
200 unsigned long timeout = jiffies + HZ;
201 int ret;
202
203 i2c->msg = msgs;
204 i2c->pos = 0;
205 i2c->nmsgs = num;
206 i2c->state = STATE_INIT;
207
208
209 while (time_before(jiffies, timeout)) {
210 kempld_get_mutex(pld);
211 ret = kempld_i2c_process(i2c);
212 kempld_release_mutex(pld);
213
214 if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR)
215 return (i2c->state == STATE_DONE) ? num : ret;
216
217 if (ret == 0)
218 timeout = jiffies + HZ;
219
220 usleep_range(5, 15);
221 }
222
223 i2c->state = STATE_ERROR;
224
225 return -ETIMEDOUT;
226}
227
228
229
230
231static void kempld_i2c_device_init(struct kempld_i2c_data *i2c)
232{
233 struct kempld_device_data *pld = i2c->pld;
234 u16 prescale_corr;
235 long prescale;
236 u8 ctrl;
237 u8 stat;
238 u8 cfg;
239
240
241 ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
242 ctrl &= ~(I2C_CTRL_EN | I2C_CTRL_IEN);
243 kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
244
245 if (bus_frequency > KEMPLD_I2C_FREQ_MAX)
246 bus_frequency = KEMPLD_I2C_FREQ_MAX;
247
248 if (pld->info.spec_major == 1)
249 prescale = pld->pld_clock / (bus_frequency * 5) - 1000;
250 else
251 prescale = pld->pld_clock / (bus_frequency * 4) - 3000;
252
253 if (prescale < 0)
254 prescale = 0;
255
256
257 prescale_corr = prescale / 1000;
258 if (prescale % 1000 >= 500)
259 prescale_corr++;
260
261 kempld_write8(pld, KEMPLD_I2C_PRELOW, prescale_corr & 0xff);
262 kempld_write8(pld, KEMPLD_I2C_PREHIGH, prescale_corr >> 8);
263
264
265 cfg = kempld_read8(pld, KEMPLD_CFG);
266 if (i2c_gpio_mux)
267 cfg |= KEMPLD_CFG_GPIO_I2C_MUX;
268 else
269 cfg &= ~KEMPLD_CFG_GPIO_I2C_MUX;
270 kempld_write8(pld, KEMPLD_CFG, cfg);
271
272
273 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_IACK);
274 ctrl |= I2C_CTRL_EN;
275 kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
276
277 stat = kempld_read8(pld, KEMPLD_I2C_STAT);
278 if (stat & I2C_STAT_BUSY)
279 kempld_write8(pld, KEMPLD_I2C_CMD, I2C_CMD_STOP);
280}
281
282static u32 kempld_i2c_func(struct i2c_adapter *adap)
283{
284 return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
285}
286
287static const struct i2c_algorithm kempld_i2c_algorithm = {
288 .master_xfer = kempld_i2c_xfer,
289 .functionality = kempld_i2c_func,
290};
291
292static struct i2c_adapter kempld_i2c_adapter = {
293 .owner = THIS_MODULE,
294 .name = "i2c-kempld",
295 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
296 .algo = &kempld_i2c_algorithm,
297};
298
299static int kempld_i2c_probe(struct platform_device *pdev)
300{
301 struct kempld_device_data *pld = dev_get_drvdata(pdev->dev.parent);
302 struct kempld_i2c_data *i2c;
303 int ret;
304 u8 ctrl;
305
306 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
307 if (!i2c)
308 return -ENOMEM;
309
310 i2c->pld = pld;
311 i2c->dev = &pdev->dev;
312 i2c->adap = kempld_i2c_adapter;
313 i2c->adap.dev.parent = i2c->dev;
314 i2c_set_adapdata(&i2c->adap, i2c);
315 platform_set_drvdata(pdev, i2c);
316
317 kempld_get_mutex(pld);
318 ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
319
320 if (ctrl & I2C_CTRL_EN)
321 i2c->was_active = true;
322
323 kempld_i2c_device_init(i2c);
324 kempld_release_mutex(pld);
325
326
327 if (i2c_bus >= -1)
328 i2c->adap.nr = i2c_bus;
329 ret = i2c_add_numbered_adapter(&i2c->adap);
330 if (ret)
331 return ret;
332
333 dev_info(i2c->dev, "I2C bus initialized at %dkHz\n",
334 bus_frequency);
335
336 return 0;
337}
338
339static int kempld_i2c_remove(struct platform_device *pdev)
340{
341 struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
342 struct kempld_device_data *pld = i2c->pld;
343 u8 ctrl;
344
345 kempld_get_mutex(pld);
346
347
348
349
350 if (!i2c->was_active) {
351 ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
352 ctrl &= ~I2C_CTRL_EN;
353 kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
354 }
355 kempld_release_mutex(pld);
356
357 i2c_del_adapter(&i2c->adap);
358
359 return 0;
360}
361
362#ifdef CONFIG_PM
363static int kempld_i2c_suspend(struct platform_device *pdev, pm_message_t state)
364{
365 struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
366 struct kempld_device_data *pld = i2c->pld;
367 u8 ctrl;
368
369 kempld_get_mutex(pld);
370 ctrl = kempld_read8(pld, KEMPLD_I2C_CTRL);
371 ctrl &= ~I2C_CTRL_EN;
372 kempld_write8(pld, KEMPLD_I2C_CTRL, ctrl);
373 kempld_release_mutex(pld);
374
375 return 0;
376}
377
378static int kempld_i2c_resume(struct platform_device *pdev)
379{
380 struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
381 struct kempld_device_data *pld = i2c->pld;
382
383 kempld_get_mutex(pld);
384 kempld_i2c_device_init(i2c);
385 kempld_release_mutex(pld);
386
387 return 0;
388}
389#else
390#define kempld_i2c_suspend NULL
391#define kempld_i2c_resume NULL
392#endif
393
394static struct platform_driver kempld_i2c_driver = {
395 .driver = {
396 .name = "kempld-i2c",
397 },
398 .probe = kempld_i2c_probe,
399 .remove = kempld_i2c_remove,
400 .suspend = kempld_i2c_suspend,
401 .resume = kempld_i2c_resume,
402};
403
404module_platform_driver(kempld_i2c_driver);
405
406MODULE_DESCRIPTION("KEM PLD I2C Driver");
407MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
408MODULE_LICENSE("GPL");
409MODULE_ALIAS("platform:kempld_i2c");
410
