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>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
21 #define I2C_ADDR_CFG 0x04
22 #define I2C_COUNT 0x08
25 #define I2C_STATUS 0x14
26 #define I2C_HSMODE_CFG 0x18
27 #define I2C_VERSION 0x1c
28 #define ADDR_DVD0 0x20
29 #define ADDR_DVD1 0x24
30 #define ADDR_STA0_DVD 0x28
34 #define STP_EN BIT(20)
35 #define FIFO_AF_LVL_MASK GENMASK(19, 16)
36 #define FIFO_AF_LVL 16
37 #define FIFO_AE_LVL_MASK GENMASK(15, 12)
38 #define FIFO_AE_LVL 12
39 #define I2C_DMA_EN BIT(11)
40 #define FULL_INTEN BIT(10)
41 #define EMPTY_INTEN BIT(9)
42 #define I2C_DVD_OPT BIT(8)
43 #define I2C_OUT_OPT BIT(7)
44 #define I2C_TRIM_OPT BIT(6)
45 #define I2C_HS_MODE BIT(4)
46 #define I2C_MODE BIT(3)
48 #define I2C_INT_EN BIT(1)
49 #define I2C_START BIT(0)
52 #define SDA_IN BIT(21)
53 #define SCL_IN BIT(20)
54 #define FIFO_FULL BIT(4)
55 #define FIFO_EMPTY BIT(3)
56 #define I2C_INT BIT(2)
57 #define I2C_RX_ACK BIT(1)
58 #define I2C_BUSY BIT(0)
61 #define I2C_RST BIT(0)
63 #define I2C_FIFO_DEEP 12
64 #define I2C_FIFO_FULL_THLD 15
65 #define I2C_FIFO_EMPTY_THLD 4
66 #define I2C_DATA_STEP 8
67 #define I2C_ADDR_DVD0_CALC(high, low) \
68 ((((high) & GENMASK(15, 0)) << 16) | ((low) & GENMASK(15, 0)))
69 #define I2C_ADDR_DVD1_CALC(high, low) \
70 (((high) & GENMASK(31, 16)) | (((low) & GENMASK(31, 16)) >> 16))
72 /* timeout (ms) for pm runtime autosuspend */
73 #define SPRD_I2C_PM_TIMEOUT 1000
75 /* SPRD i2c data structure */
77 struct i2c_adapter adap;
84 struct completion complete;
91 static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count)
93 writel(count, i2c_dev->base + I2C_COUNT);
96 static void sprd_i2c_send_stop(struct sprd_i2c *i2c_dev, int stop)
98 u32 tmp = readl(i2c_dev->base + I2C_CTL);
101 writel(tmp & ~STP_EN, i2c_dev->base + I2C_CTL);
103 writel(tmp | STP_EN, i2c_dev->base + I2C_CTL);
106 static void sprd_i2c_clear_start(struct sprd_i2c *i2c_dev)
108 u32 tmp = readl(i2c_dev->base + I2C_CTL);
110 writel(tmp & ~I2C_START, i2c_dev->base + I2C_CTL);
113 static void sprd_i2c_clear_ack(struct sprd_i2c *i2c_dev)
115 u32 tmp = readl(i2c_dev->base + I2C_STATUS);
117 writel(tmp & ~I2C_RX_ACK, i2c_dev->base + I2C_STATUS);
120 static void sprd_i2c_clear_irq(struct sprd_i2c *i2c_dev)
122 u32 tmp = readl(i2c_dev->base + I2C_STATUS);
124 writel(tmp & ~I2C_INT, i2c_dev->base + I2C_STATUS);
127 static void sprd_i2c_reset_fifo(struct sprd_i2c *i2c_dev)
129 writel(I2C_RST, i2c_dev->base + ADDR_RST);
132 static void sprd_i2c_set_devaddr(struct sprd_i2c *i2c_dev, struct i2c_msg *m)
134 writel(m->addr << 1, i2c_dev->base + I2C_ADDR_CFG);
137 static void sprd_i2c_write_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
141 for (i = 0; i < len; i++)
142 writeb(buf[i], i2c_dev->base + I2C_TX);
145 static void sprd_i2c_read_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
149 for (i = 0; i < len; i++)
150 buf[i] = readb(i2c_dev->base + I2C_RX);
153 static void sprd_i2c_set_full_thld(struct sprd_i2c *i2c_dev, u32 full_thld)
155 u32 tmp = readl(i2c_dev->base + I2C_CTL);
157 tmp &= ~FIFO_AF_LVL_MASK;
158 tmp |= full_thld << FIFO_AF_LVL;
159 writel(tmp, i2c_dev->base + I2C_CTL);
162 static void sprd_i2c_set_empty_thld(struct sprd_i2c *i2c_dev, u32 empty_thld)
164 u32 tmp = readl(i2c_dev->base + I2C_CTL);
166 tmp &= ~FIFO_AE_LVL_MASK;
167 tmp |= empty_thld << FIFO_AE_LVL;
168 writel(tmp, i2c_dev->base + I2C_CTL);
171 static void sprd_i2c_set_fifo_full_int(struct sprd_i2c *i2c_dev, int enable)
173 u32 tmp = readl(i2c_dev->base + I2C_CTL);
180 writel(tmp, i2c_dev->base + I2C_CTL);
183 static void sprd_i2c_set_fifo_empty_int(struct sprd_i2c *i2c_dev, int enable)
185 u32 tmp = readl(i2c_dev->base + I2C_CTL);
192 writel(tmp, i2c_dev->base + I2C_CTL);
195 static void sprd_i2c_opt_start(struct sprd_i2c *i2c_dev)
197 u32 tmp = readl(i2c_dev->base + I2C_CTL);
199 writel(tmp | I2C_START, i2c_dev->base + I2C_CTL);
202 static void sprd_i2c_opt_mode(struct sprd_i2c *i2c_dev, int rw)
204 u32 cmd = readl(i2c_dev->base + I2C_CTL) & ~I2C_MODE;
206 writel(cmd | rw << 3, i2c_dev->base + I2C_CTL);
209 static void sprd_i2c_data_transfer(struct sprd_i2c *i2c_dev)
211 u32 i2c_count = i2c_dev->count;
212 u32 need_tran = i2c_count <= I2C_FIFO_DEEP ? i2c_count : I2C_FIFO_DEEP;
213 struct i2c_msg *msg = i2c_dev->msg;
215 if (msg->flags & I2C_M_RD) {
216 sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, I2C_FIFO_FULL_THLD);
217 i2c_dev->count -= I2C_FIFO_FULL_THLD;
218 i2c_dev->buf += I2C_FIFO_FULL_THLD;
221 * If the read data count is larger than rx fifo full threshold,
222 * we should enable the rx fifo full interrupt to read data
225 if (i2c_dev->count >= I2C_FIFO_FULL_THLD)
226 sprd_i2c_set_fifo_full_int(i2c_dev, 1);
228 sprd_i2c_write_bytes(i2c_dev, i2c_dev->buf, need_tran);
229 i2c_dev->buf += need_tran;
230 i2c_dev->count -= need_tran;
233 * If the write data count is arger than tx fifo depth which
234 * means we can not write all data in one time, then we should
235 * enable the tx fifo empty interrupt to write again.
237 if (i2c_count > I2C_FIFO_DEEP)
238 sprd_i2c_set_fifo_empty_int(i2c_dev, 1);
242 static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
243 struct i2c_msg *msg, bool is_last_msg)
245 struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
248 i2c_dev->buf = msg->buf;
249 i2c_dev->count = msg->len;
251 reinit_completion(&i2c_dev->complete);
252 sprd_i2c_reset_fifo(i2c_dev);
253 sprd_i2c_set_devaddr(i2c_dev, msg);
254 sprd_i2c_set_count(i2c_dev, msg->len);
256 if (msg->flags & I2C_M_RD) {
257 sprd_i2c_opt_mode(i2c_dev, 1);
258 sprd_i2c_send_stop(i2c_dev, 1);
260 sprd_i2c_opt_mode(i2c_dev, 0);
261 sprd_i2c_send_stop(i2c_dev, !!is_last_msg);
265 * We should enable rx fifo full interrupt to get data when receiving
268 if (msg->flags & I2C_M_RD)
269 sprd_i2c_set_fifo_full_int(i2c_dev, 1);
271 sprd_i2c_data_transfer(i2c_dev);
273 sprd_i2c_opt_start(i2c_dev);
275 wait_for_completion(&i2c_dev->complete);
280 static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
281 struct i2c_msg *msgs, int num)
283 struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
286 ret = pm_runtime_get_sync(i2c_dev->dev);
290 for (im = 0; im < num - 1; im++) {
291 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0);
296 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im++], 1);
299 pm_runtime_mark_last_busy(i2c_dev->dev);
300 pm_runtime_put_autosuspend(i2c_dev->dev);
302 return ret < 0 ? ret : im;
305 static u32 sprd_i2c_func(struct i2c_adapter *adap)
307 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
310 static const struct i2c_algorithm sprd_i2c_algo = {
311 .master_xfer = sprd_i2c_master_xfer,
312 .functionality = sprd_i2c_func,
315 static void sprd_i2c_set_clk(struct sprd_i2c *i2c_dev, u32 freq)
317 u32 apb_clk = i2c_dev->src_clk;
319 * From I2C databook, the prescale calculation formula:
320 * prescale = freq_i2c / (4 * freq_scl) - 1;
322 u32 i2c_dvd = apb_clk / (4 * freq) - 1;
324 * From I2C databook, the high period of SCL clock is recommended as
325 * 40% (2/5), and the low period of SCL clock is recommended as 60%
326 * (3/5), then the formula should be:
327 * high = (prescale * 2 * 2) / 5
328 * low = (prescale * 2 * 3) / 5
330 u32 high = ((i2c_dvd << 1) * 2) / 5;
331 u32 low = ((i2c_dvd << 1) * 3) / 5;
332 u32 div0 = I2C_ADDR_DVD0_CALC(high, low);
333 u32 div1 = I2C_ADDR_DVD1_CALC(high, low);
335 writel(div0, i2c_dev->base + ADDR_DVD0);
336 writel(div1, i2c_dev->base + ADDR_DVD1);
338 /* Start hold timing = hold time(us) * source clock */
340 writel((6 * apb_clk) / 10000000, i2c_dev->base + ADDR_STA0_DVD);
341 else if (freq == 100000)
342 writel((4 * apb_clk) / 1000000, i2c_dev->base + ADDR_STA0_DVD);
345 static void sprd_i2c_enable(struct sprd_i2c *i2c_dev)
347 u32 tmp = I2C_DVD_OPT;
349 writel(tmp, i2c_dev->base + I2C_CTL);
351 sprd_i2c_set_full_thld(i2c_dev, I2C_FIFO_FULL_THLD);
352 sprd_i2c_set_empty_thld(i2c_dev, I2C_FIFO_EMPTY_THLD);
354 sprd_i2c_set_clk(i2c_dev, i2c_dev->bus_freq);
355 sprd_i2c_reset_fifo(i2c_dev);
356 sprd_i2c_clear_irq(i2c_dev);
358 tmp = readl(i2c_dev->base + I2C_CTL);
359 writel(tmp | I2C_EN | I2C_INT_EN, i2c_dev->base + I2C_CTL);
362 static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id)
364 struct sprd_i2c *i2c_dev = dev_id;
365 struct i2c_msg *msg = i2c_dev->msg;
366 bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
369 if (msg->flags & I2C_M_RD)
370 i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
372 i2c_tran = i2c_dev->count;
375 * If we got one ACK from slave when writing data, and we did not
376 * finish this transmission (i2c_tran is not zero), then we should
377 * continue to write data.
379 * For reading data, ack is always true, if i2c_tran is not 0 which
380 * means we still need to contine to read data from slave.
382 if (i2c_tran && ack) {
383 sprd_i2c_data_transfer(i2c_dev);
390 * If we did not get one ACK from slave when writing data, we should
391 * return -EIO to notify users.
395 else if (msg->flags & I2C_M_RD && i2c_dev->count)
396 sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, i2c_dev->count);
398 /* Transmission is done and clear ack and start operation */
399 sprd_i2c_clear_ack(i2c_dev);
400 sprd_i2c_clear_start(i2c_dev);
401 complete(&i2c_dev->complete);
406 static irqreturn_t sprd_i2c_isr(int irq, void *dev_id)
408 struct sprd_i2c *i2c_dev = dev_id;
409 struct i2c_msg *msg = i2c_dev->msg;
410 bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
413 if (msg->flags & I2C_M_RD)
414 i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
416 i2c_tran = i2c_dev->count;
419 * If we did not get one ACK from slave when writing data, then we
420 * should finish this transmission since we got some errors.
422 * When writing data, if i2c_tran == 0 which means we have writen
423 * done all data, then we can finish this transmission.
425 * When reading data, if conut < rx fifo full threshold, which
426 * means we can read all data in one time, then we can finish this
429 if (!i2c_tran || !ack) {
430 sprd_i2c_clear_start(i2c_dev);
431 sprd_i2c_clear_irq(i2c_dev);
434 sprd_i2c_set_fifo_empty_int(i2c_dev, 0);
435 sprd_i2c_set_fifo_full_int(i2c_dev, 0);
437 return IRQ_WAKE_THREAD;
440 static int sprd_i2c_clk_init(struct sprd_i2c *i2c_dev)
442 struct clk *clk_i2c, *clk_parent;
444 clk_i2c = devm_clk_get(i2c_dev->dev, "i2c");
445 if (IS_ERR(clk_i2c)) {
446 dev_warn(i2c_dev->dev, "i2c%d can't get the i2c clock\n",
451 clk_parent = devm_clk_get(i2c_dev->dev, "source");
452 if (IS_ERR(clk_parent)) {
453 dev_warn(i2c_dev->dev, "i2c%d can't get the source clock\n",
458 if (clk_set_parent(clk_i2c, clk_parent))
459 i2c_dev->src_clk = clk_get_rate(clk_i2c);
461 i2c_dev->src_clk = 26000000;
463 dev_dbg(i2c_dev->dev, "i2c%d set source clock is %d\n",
464 i2c_dev->adap.nr, i2c_dev->src_clk);
466 i2c_dev->clk = devm_clk_get(i2c_dev->dev, "enable");
467 if (IS_ERR(i2c_dev->clk)) {
468 dev_warn(i2c_dev->dev, "i2c%d can't get the enable clock\n",
476 static int sprd_i2c_probe(struct platform_device *pdev)
478 struct device *dev = &pdev->dev;
479 struct sprd_i2c *i2c_dev;
480 struct resource *res;
484 pdev->id = of_alias_get_id(dev->of_node, "i2c");
486 i2c_dev = devm_kzalloc(dev, sizeof(struct sprd_i2c), GFP_KERNEL);
490 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
491 i2c_dev->base = devm_ioremap_resource(dev, res);
492 if (IS_ERR(i2c_dev->base))
493 return PTR_ERR(i2c_dev->base);
495 i2c_dev->irq = platform_get_irq(pdev, 0);
496 if (i2c_dev->irq < 0) {
497 dev_err(&pdev->dev, "failed to get irq resource\n");
501 i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
502 init_completion(&i2c_dev->complete);
503 snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
506 i2c_dev->bus_freq = 100000;
507 i2c_dev->adap.owner = THIS_MODULE;
509 i2c_dev->adap.retries = 3;
510 i2c_dev->adap.algo = &sprd_i2c_algo;
511 i2c_dev->adap.algo_data = i2c_dev;
512 i2c_dev->adap.dev.parent = dev;
513 i2c_dev->adap.nr = pdev->id;
514 i2c_dev->adap.dev.of_node = dev->of_node;
516 if (!of_property_read_u32(dev->of_node, "clock-frequency", &prop))
517 i2c_dev->bus_freq = prop;
519 /* We only support 100k and 400k now, otherwise will return error. */
520 if (i2c_dev->bus_freq != 100000 && i2c_dev->bus_freq != 400000)
523 sprd_i2c_clk_init(i2c_dev);
524 platform_set_drvdata(pdev, i2c_dev);
526 ret = clk_prepare_enable(i2c_dev->clk);
530 sprd_i2c_enable(i2c_dev);
532 pm_runtime_set_autosuspend_delay(i2c_dev->dev, SPRD_I2C_PM_TIMEOUT);
533 pm_runtime_use_autosuspend(i2c_dev->dev);
534 pm_runtime_set_active(i2c_dev->dev);
535 pm_runtime_enable(i2c_dev->dev);
537 ret = pm_runtime_get_sync(i2c_dev->dev);
541 ret = devm_request_threaded_irq(dev, i2c_dev->irq,
542 sprd_i2c_isr, sprd_i2c_isr_thread,
543 IRQF_NO_SUSPEND | IRQF_ONESHOT,
544 pdev->name, i2c_dev);
546 dev_err(&pdev->dev, "failed to request irq %d\n", i2c_dev->irq);
550 ret = i2c_add_numbered_adapter(&i2c_dev->adap);
552 dev_err(&pdev->dev, "add adapter failed\n");
556 pm_runtime_mark_last_busy(i2c_dev->dev);
557 pm_runtime_put_autosuspend(i2c_dev->dev);
561 pm_runtime_put_noidle(i2c_dev->dev);
562 pm_runtime_disable(i2c_dev->dev);
563 clk_disable_unprepare(i2c_dev->clk);
567 static int sprd_i2c_remove(struct platform_device *pdev)
569 struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev);
572 ret = pm_runtime_get_sync(i2c_dev->dev);
576 i2c_del_adapter(&i2c_dev->adap);
577 clk_disable_unprepare(i2c_dev->clk);
579 pm_runtime_put_noidle(i2c_dev->dev);
580 pm_runtime_disable(i2c_dev->dev);
585 static int __maybe_unused sprd_i2c_suspend_noirq(struct device *dev)
587 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
589 i2c_mark_adapter_suspended(&i2c_dev->adap);
590 return pm_runtime_force_suspend(dev);
593 static int __maybe_unused sprd_i2c_resume_noirq(struct device *dev)
595 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
597 i2c_mark_adapter_resumed(&i2c_dev->adap);
598 return pm_runtime_force_resume(dev);
601 static int __maybe_unused sprd_i2c_runtime_suspend(struct device *dev)
603 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
605 clk_disable_unprepare(i2c_dev->clk);
610 static int __maybe_unused sprd_i2c_runtime_resume(struct device *dev)
612 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
615 ret = clk_prepare_enable(i2c_dev->clk);
619 sprd_i2c_enable(i2c_dev);
624 static const struct dev_pm_ops sprd_i2c_pm_ops = {
625 SET_RUNTIME_PM_OPS(sprd_i2c_runtime_suspend,
626 sprd_i2c_runtime_resume, NULL)
628 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sprd_i2c_suspend_noirq,
629 sprd_i2c_resume_noirq)
632 static const struct of_device_id sprd_i2c_of_match[] = {
633 { .compatible = "sprd,sc9860-i2c", },
637 static struct platform_driver sprd_i2c_driver = {
638 .probe = sprd_i2c_probe,
639 .remove = sprd_i2c_remove,
642 .of_match_table = sprd_i2c_of_match,
643 .pm = &sprd_i2c_pm_ops,
647 static int sprd_i2c_init(void)
649 return platform_driver_register(&sprd_i2c_driver);
651 arch_initcall_sync(sprd_i2c_init);