2 * Copyright (C) 2017 Spreadtrum Communications Inc.
4 * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
8 #include <linux/delay.h>
11 #include <linux/i2c.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm_runtime.h>
22 #define I2C_ADDR_CFG 0x04
23 #define I2C_COUNT 0x08
26 #define I2C_STATUS 0x14
27 #define I2C_HSMODE_CFG 0x18
28 #define I2C_VERSION 0x1c
29 #define ADDR_DVD0 0x20
30 #define ADDR_DVD1 0x24
31 #define ADDR_STA0_DVD 0x28
35 #define STP_EN BIT(20)
36 #define FIFO_AF_LVL_MASK GENMASK(19, 16)
37 #define FIFO_AF_LVL 16
38 #define FIFO_AE_LVL_MASK GENMASK(15, 12)
39 #define FIFO_AE_LVL 12
40 #define I2C_DMA_EN BIT(11)
41 #define FULL_INTEN BIT(10)
42 #define EMPTY_INTEN BIT(9)
43 #define I2C_DVD_OPT BIT(8)
44 #define I2C_OUT_OPT BIT(7)
45 #define I2C_TRIM_OPT BIT(6)
46 #define I2C_HS_MODE BIT(4)
47 #define I2C_MODE BIT(3)
49 #define I2C_INT_EN BIT(1)
50 #define I2C_START BIT(0)
53 #define SDA_IN BIT(21)
54 #define SCL_IN BIT(20)
55 #define FIFO_FULL BIT(4)
56 #define FIFO_EMPTY BIT(3)
57 #define I2C_INT BIT(2)
58 #define I2C_RX_ACK BIT(1)
59 #define I2C_BUSY BIT(0)
62 #define I2C_RST BIT(0)
64 #define I2C_FIFO_DEEP 12
65 #define I2C_FIFO_FULL_THLD 15
66 #define I2C_FIFO_EMPTY_THLD 4
67 #define I2C_DATA_STEP 8
68 #define I2C_ADDR_DVD0_CALC(high, low) \
69 ((((high) & GENMASK(15, 0)) << 16) | ((low) & GENMASK(15, 0)))
70 #define I2C_ADDR_DVD1_CALC(high, low) \
71 (((high) & GENMASK(31, 16)) | (((low) & GENMASK(31, 16)) >> 16))
73 /* timeout (ms) for pm runtime autosuspend */
74 #define SPRD_I2C_PM_TIMEOUT 1000
76 /* SPRD i2c data structure */
78 struct i2c_adapter adap;
85 struct completion complete;
92 static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count)
94 writel(count, i2c_dev->base + I2C_COUNT);
97 static void sprd_i2c_send_stop(struct sprd_i2c *i2c_dev, int stop)
99 u32 tmp = readl(i2c_dev->base + I2C_CTL);
102 writel(tmp & ~STP_EN, i2c_dev->base + I2C_CTL);
104 writel(tmp | STP_EN, i2c_dev->base + I2C_CTL);
107 static void sprd_i2c_clear_start(struct sprd_i2c *i2c_dev)
109 u32 tmp = readl(i2c_dev->base + I2C_CTL);
111 writel(tmp & ~I2C_START, i2c_dev->base + I2C_CTL);
114 static void sprd_i2c_clear_ack(struct sprd_i2c *i2c_dev)
116 u32 tmp = readl(i2c_dev->base + I2C_STATUS);
118 writel(tmp & ~I2C_RX_ACK, i2c_dev->base + I2C_STATUS);
121 static void sprd_i2c_clear_irq(struct sprd_i2c *i2c_dev)
123 u32 tmp = readl(i2c_dev->base + I2C_STATUS);
125 writel(tmp & ~I2C_INT, i2c_dev->base + I2C_STATUS);
128 static void sprd_i2c_reset_fifo(struct sprd_i2c *i2c_dev)
130 writel(I2C_RST, i2c_dev->base + ADDR_RST);
133 static void sprd_i2c_set_devaddr(struct sprd_i2c *i2c_dev, struct i2c_msg *m)
135 writel(m->addr << 1, i2c_dev->base + I2C_ADDR_CFG);
138 static void sprd_i2c_write_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
142 for (i = 0; i < len; i++)
143 writeb(buf[i], i2c_dev->base + I2C_TX);
146 static void sprd_i2c_read_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
150 for (i = 0; i < len; i++)
151 buf[i] = readb(i2c_dev->base + I2C_RX);
154 static void sprd_i2c_set_full_thld(struct sprd_i2c *i2c_dev, u32 full_thld)
156 u32 tmp = readl(i2c_dev->base + I2C_CTL);
158 tmp &= ~FIFO_AF_LVL_MASK;
159 tmp |= full_thld << FIFO_AF_LVL;
160 writel(tmp, i2c_dev->base + I2C_CTL);
163 static void sprd_i2c_set_empty_thld(struct sprd_i2c *i2c_dev, u32 empty_thld)
165 u32 tmp = readl(i2c_dev->base + I2C_CTL);
167 tmp &= ~FIFO_AE_LVL_MASK;
168 tmp |= empty_thld << FIFO_AE_LVL;
169 writel(tmp, i2c_dev->base + I2C_CTL);
172 static void sprd_i2c_set_fifo_full_int(struct sprd_i2c *i2c_dev, int enable)
174 u32 tmp = readl(i2c_dev->base + I2C_CTL);
181 writel(tmp, i2c_dev->base + I2C_CTL);
184 static void sprd_i2c_set_fifo_empty_int(struct sprd_i2c *i2c_dev, int enable)
186 u32 tmp = readl(i2c_dev->base + I2C_CTL);
193 writel(tmp, i2c_dev->base + I2C_CTL);
196 static void sprd_i2c_opt_start(struct sprd_i2c *i2c_dev)
198 u32 tmp = readl(i2c_dev->base + I2C_CTL);
200 writel(tmp | I2C_START, i2c_dev->base + I2C_CTL);
203 static void sprd_i2c_opt_mode(struct sprd_i2c *i2c_dev, int rw)
205 u32 cmd = readl(i2c_dev->base + I2C_CTL) & ~I2C_MODE;
207 writel(cmd | rw << 3, i2c_dev->base + I2C_CTL);
210 static void sprd_i2c_data_transfer(struct sprd_i2c *i2c_dev)
212 u32 i2c_count = i2c_dev->count;
213 u32 need_tran = i2c_count <= I2C_FIFO_DEEP ? i2c_count : I2C_FIFO_DEEP;
214 struct i2c_msg *msg = i2c_dev->msg;
216 if (msg->flags & I2C_M_RD) {
217 sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, I2C_FIFO_FULL_THLD);
218 i2c_dev->count -= I2C_FIFO_FULL_THLD;
219 i2c_dev->buf += I2C_FIFO_FULL_THLD;
222 * If the read data count is larger than rx fifo full threshold,
223 * we should enable the rx fifo full interrupt to read data
226 if (i2c_dev->count >= I2C_FIFO_FULL_THLD)
227 sprd_i2c_set_fifo_full_int(i2c_dev, 1);
229 sprd_i2c_write_bytes(i2c_dev, i2c_dev->buf, need_tran);
230 i2c_dev->buf += need_tran;
231 i2c_dev->count -= need_tran;
234 * If the write data count is arger than tx fifo depth which
235 * means we can not write all data in one time, then we should
236 * enable the tx fifo empty interrupt to write again.
238 if (i2c_count > I2C_FIFO_DEEP)
239 sprd_i2c_set_fifo_empty_int(i2c_dev, 1);
243 static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
244 struct i2c_msg *msg, bool is_last_msg)
246 struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
249 i2c_dev->buf = msg->buf;
250 i2c_dev->count = msg->len;
252 reinit_completion(&i2c_dev->complete);
253 sprd_i2c_reset_fifo(i2c_dev);
254 sprd_i2c_set_devaddr(i2c_dev, msg);
255 sprd_i2c_set_count(i2c_dev, msg->len);
257 if (msg->flags & I2C_M_RD) {
258 sprd_i2c_opt_mode(i2c_dev, 1);
259 sprd_i2c_send_stop(i2c_dev, 1);
261 sprd_i2c_opt_mode(i2c_dev, 0);
262 sprd_i2c_send_stop(i2c_dev, !!is_last_msg);
266 * We should enable rx fifo full interrupt to get data when receiving
269 if (msg->flags & I2C_M_RD)
270 sprd_i2c_set_fifo_full_int(i2c_dev, 1);
272 sprd_i2c_data_transfer(i2c_dev);
274 sprd_i2c_opt_start(i2c_dev);
276 wait_for_completion(&i2c_dev->complete);
281 static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
282 struct i2c_msg *msgs, int num)
284 struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
287 ret = pm_runtime_get_sync(i2c_dev->dev);
291 for (im = 0; im < num - 1; im++) {
292 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0);
297 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im++], 1);
300 pm_runtime_mark_last_busy(i2c_dev->dev);
301 pm_runtime_put_autosuspend(i2c_dev->dev);
303 return ret < 0 ? ret : im;
306 static u32 sprd_i2c_func(struct i2c_adapter *adap)
308 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
311 static const struct i2c_algorithm sprd_i2c_algo = {
312 .master_xfer = sprd_i2c_master_xfer,
313 .functionality = sprd_i2c_func,
316 static void sprd_i2c_set_clk(struct sprd_i2c *i2c_dev, u32 freq)
318 u32 apb_clk = i2c_dev->src_clk;
320 * From I2C databook, the prescale calculation formula:
321 * prescale = freq_i2c / (4 * freq_scl) - 1;
323 u32 i2c_dvd = apb_clk / (4 * freq) - 1;
325 * From I2C databook, the high period of SCL clock is recommended as
326 * 40% (2/5), and the low period of SCL clock is recommended as 60%
327 * (3/5), then the formula should be:
328 * high = (prescale * 2 * 2) / 5
329 * low = (prescale * 2 * 3) / 5
331 u32 high = ((i2c_dvd << 1) * 2) / 5;
332 u32 low = ((i2c_dvd << 1) * 3) / 5;
333 u32 div0 = I2C_ADDR_DVD0_CALC(high, low);
334 u32 div1 = I2C_ADDR_DVD1_CALC(high, low);
336 writel(div0, i2c_dev->base + ADDR_DVD0);
337 writel(div1, i2c_dev->base + ADDR_DVD1);
339 /* Start hold timing = hold time(us) * source clock */
340 if (freq == I2C_MAX_FAST_MODE_FREQ)
341 writel((6 * apb_clk) / 10000000, i2c_dev->base + ADDR_STA0_DVD);
342 else if (freq == I2C_MAX_STANDARD_MODE_FREQ)
343 writel((4 * apb_clk) / 1000000, i2c_dev->base + ADDR_STA0_DVD);
346 static void sprd_i2c_enable(struct sprd_i2c *i2c_dev)
348 u32 tmp = I2C_DVD_OPT;
350 writel(tmp, i2c_dev->base + I2C_CTL);
352 sprd_i2c_set_full_thld(i2c_dev, I2C_FIFO_FULL_THLD);
353 sprd_i2c_set_empty_thld(i2c_dev, I2C_FIFO_EMPTY_THLD);
355 sprd_i2c_set_clk(i2c_dev, i2c_dev->bus_freq);
356 sprd_i2c_reset_fifo(i2c_dev);
357 sprd_i2c_clear_irq(i2c_dev);
359 tmp = readl(i2c_dev->base + I2C_CTL);
360 writel(tmp | I2C_EN | I2C_INT_EN, i2c_dev->base + I2C_CTL);
363 static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id)
365 struct sprd_i2c *i2c_dev = dev_id;
366 struct i2c_msg *msg = i2c_dev->msg;
367 bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
370 if (msg->flags & I2C_M_RD)
371 i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
373 i2c_tran = i2c_dev->count;
376 * If we got one ACK from slave when writing data, and we did not
377 * finish this transmission (i2c_tran is not zero), then we should
378 * continue to write data.
380 * For reading data, ack is always true, if i2c_tran is not 0 which
381 * means we still need to contine to read data from slave.
383 if (i2c_tran && ack) {
384 sprd_i2c_data_transfer(i2c_dev);
391 * If we did not get one ACK from slave when writing data, we should
392 * return -EIO to notify users.
396 else if (msg->flags & I2C_M_RD && i2c_dev->count)
397 sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, i2c_dev->count);
399 /* Transmission is done and clear ack and start operation */
400 sprd_i2c_clear_ack(i2c_dev);
401 sprd_i2c_clear_start(i2c_dev);
402 complete(&i2c_dev->complete);
407 static irqreturn_t sprd_i2c_isr(int irq, void *dev_id)
409 struct sprd_i2c *i2c_dev = dev_id;
410 struct i2c_msg *msg = i2c_dev->msg;
411 bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
414 if (msg->flags & I2C_M_RD)
415 i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
417 i2c_tran = i2c_dev->count;
420 * If we did not get one ACK from slave when writing data, then we
421 * should finish this transmission since we got some errors.
423 * When writing data, if i2c_tran == 0 which means we have writen
424 * done all data, then we can finish this transmission.
426 * When reading data, if conut < rx fifo full threshold, which
427 * means we can read all data in one time, then we can finish this
430 if (!i2c_tran || !ack) {
431 sprd_i2c_clear_start(i2c_dev);
432 sprd_i2c_clear_irq(i2c_dev);
435 sprd_i2c_set_fifo_empty_int(i2c_dev, 0);
436 sprd_i2c_set_fifo_full_int(i2c_dev, 0);
438 return IRQ_WAKE_THREAD;
441 static int sprd_i2c_clk_init(struct sprd_i2c *i2c_dev)
443 struct clk *clk_i2c, *clk_parent;
445 clk_i2c = devm_clk_get(i2c_dev->dev, "i2c");
446 if (IS_ERR(clk_i2c)) {
447 dev_warn(i2c_dev->dev, "i2c%d can't get the i2c clock\n",
452 clk_parent = devm_clk_get(i2c_dev->dev, "source");
453 if (IS_ERR(clk_parent)) {
454 dev_warn(i2c_dev->dev, "i2c%d can't get the source clock\n",
459 if (clk_set_parent(clk_i2c, clk_parent))
460 i2c_dev->src_clk = clk_get_rate(clk_i2c);
462 i2c_dev->src_clk = 26000000;
464 dev_dbg(i2c_dev->dev, "i2c%d set source clock is %d\n",
465 i2c_dev->adap.nr, i2c_dev->src_clk);
467 i2c_dev->clk = devm_clk_get(i2c_dev->dev, "enable");
468 if (IS_ERR(i2c_dev->clk)) {
469 dev_err(i2c_dev->dev, "i2c%d can't get the enable clock\n",
471 return PTR_ERR(i2c_dev->clk);
477 static int sprd_i2c_probe(struct platform_device *pdev)
479 struct device *dev = &pdev->dev;
480 struct sprd_i2c *i2c_dev;
484 pdev->id = of_alias_get_id(dev->of_node, "i2c");
486 i2c_dev = devm_kzalloc(dev, sizeof(struct sprd_i2c), GFP_KERNEL);
490 i2c_dev->base = devm_platform_ioremap_resource(pdev, 0);
491 if (IS_ERR(i2c_dev->base))
492 return PTR_ERR(i2c_dev->base);
494 i2c_dev->irq = platform_get_irq(pdev, 0);
495 if (i2c_dev->irq < 0) {
496 dev_err(&pdev->dev, "failed to get irq resource\n");
500 i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
501 init_completion(&i2c_dev->complete);
502 snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
505 i2c_dev->bus_freq = I2C_MAX_STANDARD_MODE_FREQ;
506 i2c_dev->adap.owner = THIS_MODULE;
508 i2c_dev->adap.retries = 3;
509 i2c_dev->adap.algo = &sprd_i2c_algo;
510 i2c_dev->adap.algo_data = i2c_dev;
511 i2c_dev->adap.dev.parent = dev;
512 i2c_dev->adap.nr = pdev->id;
513 i2c_dev->adap.dev.of_node = dev->of_node;
515 if (!of_property_read_u32(dev->of_node, "clock-frequency", &prop))
516 i2c_dev->bus_freq = prop;
518 /* We only support 100k and 400k now, otherwise will return error. */
519 if (i2c_dev->bus_freq != I2C_MAX_STANDARD_MODE_FREQ &&
520 i2c_dev->bus_freq != I2C_MAX_FAST_MODE_FREQ)
523 ret = sprd_i2c_clk_init(i2c_dev);
527 platform_set_drvdata(pdev, i2c_dev);
529 ret = clk_prepare_enable(i2c_dev->clk);
533 sprd_i2c_enable(i2c_dev);
535 pm_runtime_set_autosuspend_delay(i2c_dev->dev, SPRD_I2C_PM_TIMEOUT);
536 pm_runtime_use_autosuspend(i2c_dev->dev);
537 pm_runtime_set_active(i2c_dev->dev);
538 pm_runtime_enable(i2c_dev->dev);
540 ret = pm_runtime_get_sync(i2c_dev->dev);
544 ret = devm_request_threaded_irq(dev, i2c_dev->irq,
545 sprd_i2c_isr, sprd_i2c_isr_thread,
546 IRQF_NO_SUSPEND | IRQF_ONESHOT,
547 pdev->name, i2c_dev);
549 dev_err(&pdev->dev, "failed to request irq %d\n", i2c_dev->irq);
553 ret = i2c_add_numbered_adapter(&i2c_dev->adap);
555 dev_err(&pdev->dev, "add adapter failed\n");
559 pm_runtime_mark_last_busy(i2c_dev->dev);
560 pm_runtime_put_autosuspend(i2c_dev->dev);
564 pm_runtime_put_noidle(i2c_dev->dev);
565 pm_runtime_disable(i2c_dev->dev);
566 clk_disable_unprepare(i2c_dev->clk);
570 static int sprd_i2c_remove(struct platform_device *pdev)
572 struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev);
575 ret = pm_runtime_get_sync(i2c_dev->dev);
579 i2c_del_adapter(&i2c_dev->adap);
580 clk_disable_unprepare(i2c_dev->clk);
582 pm_runtime_put_noidle(i2c_dev->dev);
583 pm_runtime_disable(i2c_dev->dev);
588 static int __maybe_unused sprd_i2c_suspend_noirq(struct device *dev)
590 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
592 i2c_mark_adapter_suspended(&i2c_dev->adap);
593 return pm_runtime_force_suspend(dev);
596 static int __maybe_unused sprd_i2c_resume_noirq(struct device *dev)
598 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
600 i2c_mark_adapter_resumed(&i2c_dev->adap);
601 return pm_runtime_force_resume(dev);
604 static int __maybe_unused sprd_i2c_runtime_suspend(struct device *dev)
606 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
608 clk_disable_unprepare(i2c_dev->clk);
613 static int __maybe_unused sprd_i2c_runtime_resume(struct device *dev)
615 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
618 ret = clk_prepare_enable(i2c_dev->clk);
622 sprd_i2c_enable(i2c_dev);
627 static const struct dev_pm_ops sprd_i2c_pm_ops = {
628 SET_RUNTIME_PM_OPS(sprd_i2c_runtime_suspend,
629 sprd_i2c_runtime_resume, NULL)
631 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sprd_i2c_suspend_noirq,
632 sprd_i2c_resume_noirq)
635 static const struct of_device_id sprd_i2c_of_match[] = {
636 { .compatible = "sprd,sc9860-i2c", },
640 static struct platform_driver sprd_i2c_driver = {
641 .probe = sprd_i2c_probe,
642 .remove = sprd_i2c_remove,
645 .of_match_table = sprd_i2c_of_match,
646 .pm = &sprd_i2c_pm_ops,
650 module_platform_driver(sprd_i2c_driver);
652 MODULE_DESCRIPTION("Spreadtrum I2C master controller driver");
653 MODULE_LICENSE("GPL v2");