1 // SPDX-License-Identifier: GPL-2.0
3 * HiSilicon I2C Controller Driver for Kunpeng SoC
5 * Copyright (c) 2021 HiSilicon Technologies Co., Ltd.
8 #include <linux/bits.h>
9 #include <linux/bitfield.h>
10 #include <linux/clk.h>
11 #include <linux/completion.h>
12 #include <linux/i2c.h>
13 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19 #include <linux/units.h>
21 #define HISI_I2C_FRAME_CTRL 0x0000
22 #define HISI_I2C_FRAME_CTRL_SPEED_MODE GENMASK(1, 0)
23 #define HISI_I2C_FRAME_CTRL_ADDR_TEN BIT(2)
24 #define HISI_I2C_SLV_ADDR 0x0004
25 #define HISI_I2C_SLV_ADDR_VAL GENMASK(9, 0)
26 #define HISI_I2C_SLV_ADDR_GC_S_MODE BIT(10)
27 #define HISI_I2C_SLV_ADDR_GC_S_EN BIT(11)
28 #define HISI_I2C_CMD_TXDATA 0x0008
29 #define HISI_I2C_CMD_TXDATA_DATA GENMASK(7, 0)
30 #define HISI_I2C_CMD_TXDATA_RW BIT(8)
31 #define HISI_I2C_CMD_TXDATA_P_EN BIT(9)
32 #define HISI_I2C_CMD_TXDATA_SR_EN BIT(10)
33 #define HISI_I2C_RXDATA 0x000c
34 #define HISI_I2C_RXDATA_DATA GENMASK(7, 0)
35 #define HISI_I2C_SS_SCL_HCNT 0x0010
36 #define HISI_I2C_SS_SCL_LCNT 0x0014
37 #define HISI_I2C_FS_SCL_HCNT 0x0018
38 #define HISI_I2C_FS_SCL_LCNT 0x001c
39 #define HISI_I2C_HS_SCL_HCNT 0x0020
40 #define HISI_I2C_HS_SCL_LCNT 0x0024
41 #define HISI_I2C_FIFO_CTRL 0x0028
42 #define HISI_I2C_FIFO_RX_CLR BIT(0)
43 #define HISI_I2C_FIFO_TX_CLR BIT(1)
44 #define HISI_I2C_FIFO_RX_AF_THRESH GENMASK(7, 2)
45 #define HISI_I2C_FIFO_TX_AE_THRESH GENMASK(13, 8)
46 #define HISI_I2C_FIFO_STATE 0x002c
47 #define HISI_I2C_FIFO_STATE_RX_RERR BIT(0)
48 #define HISI_I2C_FIFO_STATE_RX_WERR BIT(1)
49 #define HISI_I2C_FIFO_STATE_RX_EMPTY BIT(3)
50 #define HISI_I2C_FIFO_STATE_TX_RERR BIT(6)
51 #define HISI_I2C_FIFO_STATE_TX_WERR BIT(7)
52 #define HISI_I2C_FIFO_STATE_TX_FULL BIT(11)
53 #define HISI_I2C_SDA_HOLD 0x0030
54 #define HISI_I2C_SDA_HOLD_TX GENMASK(15, 0)
55 #define HISI_I2C_SDA_HOLD_RX GENMASK(23, 16)
56 #define HISI_I2C_FS_SPK_LEN 0x0038
57 #define HISI_I2C_FS_SPK_LEN_CNT GENMASK(7, 0)
58 #define HISI_I2C_HS_SPK_LEN 0x003c
59 #define HISI_I2C_HS_SPK_LEN_CNT GENMASK(7, 0)
60 #define HISI_I2C_INT_MSTAT 0x0044
61 #define HISI_I2C_INT_CLR 0x0048
62 #define HISI_I2C_INT_MASK 0x004C
63 #define HISI_I2C_TRANS_STATE 0x0050
64 #define HISI_I2C_TRANS_ERR 0x0054
65 #define HISI_I2C_VERSION 0x0058
67 #define HISI_I2C_INT_ALL GENMASK(4, 0)
68 #define HISI_I2C_INT_TRANS_CPLT BIT(0)
69 #define HISI_I2C_INT_TRANS_ERR BIT(1)
70 #define HISI_I2C_INT_FIFO_ERR BIT(2)
71 #define HISI_I2C_INT_RX_FULL BIT(3)
72 #define HISI_I2C_INT_TX_EMPTY BIT(4)
73 #define HISI_I2C_INT_ERR \
74 (HISI_I2C_INT_TRANS_ERR | HISI_I2C_INT_FIFO_ERR)
76 #define HISI_I2C_STD_SPEED_MODE 0
77 #define HISI_I2C_FAST_SPEED_MODE 1
78 #define HISI_I2C_HIGH_SPEED_MODE 2
80 #define HISI_I2C_TX_FIFO_DEPTH 64
81 #define HISI_I2C_RX_FIFO_DEPTH 64
82 #define HISI_I2C_TX_F_AE_THRESH 1
83 #define HISI_I2C_RX_F_AF_THRESH 60
85 #define NSEC_TO_CYCLES(ns, clk_rate_khz) \
86 DIV_ROUND_UP_ULL((clk_rate_khz) * (ns), NSEC_PER_MSEC)
88 struct hisi_i2c_controller {
89 struct i2c_adapter adapter;
95 /* Intermediates for recording the transfer process */
96 struct completion *completion;
106 /* I2C bus configuration */
107 struct i2c_timings t;
112 static void hisi_i2c_enable_int(struct hisi_i2c_controller *ctlr, u32 mask)
114 writel_relaxed(mask, ctlr->iobase + HISI_I2C_INT_MASK);
117 static void hisi_i2c_disable_int(struct hisi_i2c_controller *ctlr, u32 mask)
119 writel_relaxed((~mask) & HISI_I2C_INT_ALL, ctlr->iobase + HISI_I2C_INT_MASK);
122 static void hisi_i2c_clear_int(struct hisi_i2c_controller *ctlr, u32 mask)
124 writel_relaxed(mask, ctlr->iobase + HISI_I2C_INT_CLR);
127 static void hisi_i2c_handle_errors(struct hisi_i2c_controller *ctlr)
129 u32 int_err = ctlr->xfer_err, reg;
131 if (int_err & HISI_I2C_INT_FIFO_ERR) {
132 reg = readl(ctlr->iobase + HISI_I2C_FIFO_STATE);
134 if (reg & HISI_I2C_FIFO_STATE_RX_RERR)
135 dev_err(ctlr->dev, "rx fifo error read\n");
137 if (reg & HISI_I2C_FIFO_STATE_RX_WERR)
138 dev_err(ctlr->dev, "rx fifo error write\n");
140 if (reg & HISI_I2C_FIFO_STATE_TX_RERR)
141 dev_err(ctlr->dev, "tx fifo error read\n");
143 if (reg & HISI_I2C_FIFO_STATE_TX_WERR)
144 dev_err(ctlr->dev, "tx fifo error write\n");
148 static int hisi_i2c_start_xfer(struct hisi_i2c_controller *ctlr)
150 struct i2c_msg *msg = ctlr->msgs;
153 reg = readl(ctlr->iobase + HISI_I2C_FRAME_CTRL);
154 reg &= ~HISI_I2C_FRAME_CTRL_ADDR_TEN;
155 if (msg->flags & I2C_M_TEN)
156 reg |= HISI_I2C_FRAME_CTRL_ADDR_TEN;
157 writel(reg, ctlr->iobase + HISI_I2C_FRAME_CTRL);
159 reg = readl(ctlr->iobase + HISI_I2C_SLV_ADDR);
160 reg &= ~HISI_I2C_SLV_ADDR_VAL;
161 reg |= FIELD_PREP(HISI_I2C_SLV_ADDR_VAL, msg->addr);
162 writel(reg, ctlr->iobase + HISI_I2C_SLV_ADDR);
164 reg = readl(ctlr->iobase + HISI_I2C_FIFO_CTRL);
165 reg |= HISI_I2C_FIFO_RX_CLR | HISI_I2C_FIFO_TX_CLR;
166 writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL);
167 reg &= ~(HISI_I2C_FIFO_RX_CLR | HISI_I2C_FIFO_TX_CLR);
168 writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL);
170 hisi_i2c_clear_int(ctlr, HISI_I2C_INT_ALL);
171 hisi_i2c_enable_int(ctlr, HISI_I2C_INT_ALL);
176 static void hisi_i2c_reset_xfer(struct hisi_i2c_controller *ctlr)
180 ctlr->msg_tx_idx = 0;
181 ctlr->msg_rx_idx = 0;
182 ctlr->buf_tx_idx = 0;
183 ctlr->buf_rx_idx = 0;
187 * Initialize the transfer information and start the I2C bus transfer.
188 * We only configure the transfer and do some pre/post works here, and
189 * wait for the transfer done. The major transfer process is performed
190 * in the IRQ handler.
192 static int hisi_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
195 struct hisi_i2c_controller *ctlr = i2c_get_adapdata(adap);
196 DECLARE_COMPLETION_ONSTACK(done);
199 hisi_i2c_reset_xfer(ctlr);
200 ctlr->completion = &done;
204 hisi_i2c_start_xfer(ctlr);
206 if (!wait_for_completion_timeout(ctlr->completion, adap->timeout)) {
207 hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL);
208 synchronize_irq(ctlr->irq);
209 i2c_recover_bus(&ctlr->adapter);
210 dev_err(ctlr->dev, "bus transfer timeout\n");
214 if (ctlr->xfer_err) {
215 hisi_i2c_handle_errors(ctlr);
219 hisi_i2c_reset_xfer(ctlr);
220 ctlr->completion = NULL;
225 static u32 hisi_i2c_functionality(struct i2c_adapter *adap)
227 return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
230 static const struct i2c_algorithm hisi_i2c_algo = {
231 .master_xfer = hisi_i2c_master_xfer,
232 .functionality = hisi_i2c_functionality,
235 static int hisi_i2c_read_rx_fifo(struct hisi_i2c_controller *ctlr)
237 struct i2c_msg *cur_msg;
240 while (ctlr->msg_rx_idx < ctlr->msg_num) {
241 cur_msg = ctlr->msgs + ctlr->msg_rx_idx;
243 if (!(cur_msg->flags & I2C_M_RD)) {
248 fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE);
249 while (!(fifo_state & HISI_I2C_FIFO_STATE_RX_EMPTY) &&
250 ctlr->buf_rx_idx < cur_msg->len) {
251 cur_msg->buf[ctlr->buf_rx_idx++] = readl(ctlr->iobase + HISI_I2C_RXDATA);
252 fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE);
255 if (ctlr->buf_rx_idx == cur_msg->len) {
256 ctlr->buf_rx_idx = 0;
260 if (fifo_state & HISI_I2C_FIFO_STATE_RX_EMPTY)
267 static void hisi_i2c_xfer_msg(struct hisi_i2c_controller *ctlr)
269 int max_write = HISI_I2C_TX_FIFO_DEPTH;
270 bool need_restart = false, last_msg;
271 struct i2c_msg *cur_msg;
274 while (ctlr->msg_tx_idx < ctlr->msg_num) {
275 cur_msg = ctlr->msgs + ctlr->msg_tx_idx;
276 last_msg = (ctlr->msg_tx_idx == ctlr->msg_num - 1);
278 /* Signal the SR bit when we start transferring a new message */
279 if (ctlr->msg_tx_idx && !ctlr->buf_tx_idx)
282 fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE);
283 while (!(fifo_state & HISI_I2C_FIFO_STATE_TX_FULL) &&
284 ctlr->buf_tx_idx < cur_msg->len && max_write) {
288 cmd |= HISI_I2C_CMD_TXDATA_SR_EN;
289 need_restart = false;
292 /* Signal the STOP bit at the last frame of the last message */
293 if (ctlr->buf_tx_idx == cur_msg->len - 1 && last_msg)
294 cmd |= HISI_I2C_CMD_TXDATA_P_EN;
296 if (cur_msg->flags & I2C_M_RD)
297 cmd |= HISI_I2C_CMD_TXDATA_RW;
299 cmd |= FIELD_PREP(HISI_I2C_CMD_TXDATA_DATA,
300 cur_msg->buf[ctlr->buf_tx_idx]);
302 writel(cmd, ctlr->iobase + HISI_I2C_CMD_TXDATA);
306 fifo_state = readl(ctlr->iobase + HISI_I2C_FIFO_STATE);
309 /* Update the transfer index after per message transfer is done. */
310 if (ctlr->buf_tx_idx == cur_msg->len) {
311 ctlr->buf_tx_idx = 0;
315 if ((fifo_state & HISI_I2C_FIFO_STATE_TX_FULL) ||
321 * Disable the TX_EMPTY interrupt after finishing all the messages to
322 * avoid overwhelming the CPU.
324 if (ctlr->msg_tx_idx == ctlr->msg_num)
325 hisi_i2c_disable_int(ctlr, HISI_I2C_INT_TX_EMPTY);
328 static irqreturn_t hisi_i2c_irq(int irq, void *context)
330 struct hisi_i2c_controller *ctlr = context;
334 * Don't handle the interrupt if cltr->completion is NULL. We may
335 * reach here because the interrupt is spurious or the transfer is
336 * started by another port (e.g. firmware) rather than us.
338 if (!ctlr->completion)
341 int_stat = readl(ctlr->iobase + HISI_I2C_INT_MSTAT);
342 hisi_i2c_clear_int(ctlr, int_stat);
343 if (!(int_stat & HISI_I2C_INT_ALL))
346 if (int_stat & HISI_I2C_INT_TX_EMPTY)
347 hisi_i2c_xfer_msg(ctlr);
349 if (int_stat & HISI_I2C_INT_ERR) {
350 ctlr->xfer_err = int_stat;
354 /* Drain the rx fifo before finish the transfer */
355 if (int_stat & (HISI_I2C_INT_TRANS_CPLT | HISI_I2C_INT_RX_FULL))
356 hisi_i2c_read_rx_fifo(ctlr);
360 * Only use TRANS_CPLT to indicate the completion. On error cases we'll
361 * get two interrupts, INT_ERR first then TRANS_CPLT.
363 if (int_stat & HISI_I2C_INT_TRANS_CPLT) {
364 hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL);
365 hisi_i2c_clear_int(ctlr, HISI_I2C_INT_ALL);
366 complete(ctlr->completion);
373 * Helper function for calculating and configuring the HIGH and LOW
374 * periods of SCL clock. The caller will pass the ratio of the
375 * counts (divide / divisor) according to the target speed mode,
376 * and the target registers.
378 static void hisi_i2c_set_scl(struct hisi_i2c_controller *ctlr,
379 u32 divide, u32 divisor,
380 u32 reg_hcnt, u32 reg_lcnt)
382 u32 total_cnt, t_scl_hcnt, t_scl_lcnt, scl_fall_cnt, scl_rise_cnt;
383 u32 scl_hcnt, scl_lcnt;
385 /* Total SCL clock cycles per speed period */
386 total_cnt = DIV_ROUND_UP_ULL(ctlr->clk_rate_khz * HZ_PER_KHZ, ctlr->t.bus_freq_hz);
387 /* Total HIGH level SCL clock cycles including edges */
388 t_scl_hcnt = DIV_ROUND_UP_ULL(total_cnt * divide, divisor);
389 /* Total LOW level SCL clock cycles including edges */
390 t_scl_lcnt = total_cnt - t_scl_hcnt;
391 /* Fall edge SCL clock cycles */
392 scl_fall_cnt = NSEC_TO_CYCLES(ctlr->t.scl_fall_ns, ctlr->clk_rate_khz);
393 /* Rise edge SCL clock cycles */
394 scl_rise_cnt = NSEC_TO_CYCLES(ctlr->t.scl_rise_ns, ctlr->clk_rate_khz);
396 /* Calculated HIGH and LOW periods of SCL clock */
397 scl_hcnt = t_scl_hcnt - ctlr->spk_len - 7 - scl_fall_cnt;
398 scl_lcnt = t_scl_lcnt - 1 - scl_rise_cnt;
400 writel(scl_hcnt, ctlr->iobase + reg_hcnt);
401 writel(scl_lcnt, ctlr->iobase + reg_lcnt);
404 static void hisi_i2c_configure_bus(struct hisi_i2c_controller *ctlr)
406 u32 reg, sda_hold_cnt, speed_mode;
408 i2c_parse_fw_timings(ctlr->dev, &ctlr->t, true);
409 ctlr->spk_len = NSEC_TO_CYCLES(ctlr->t.digital_filter_width_ns, ctlr->clk_rate_khz);
411 switch (ctlr->t.bus_freq_hz) {
412 case I2C_MAX_FAST_MODE_FREQ:
413 speed_mode = HISI_I2C_FAST_SPEED_MODE;
414 hisi_i2c_set_scl(ctlr, 26, 76, HISI_I2C_FS_SCL_HCNT, HISI_I2C_FS_SCL_LCNT);
416 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
417 speed_mode = HISI_I2C_HIGH_SPEED_MODE;
418 hisi_i2c_set_scl(ctlr, 6, 22, HISI_I2C_HS_SCL_HCNT, HISI_I2C_HS_SCL_LCNT);
420 case I2C_MAX_STANDARD_MODE_FREQ:
422 speed_mode = HISI_I2C_STD_SPEED_MODE;
424 /* For default condition force the bus speed to standard mode. */
425 ctlr->t.bus_freq_hz = I2C_MAX_STANDARD_MODE_FREQ;
426 hisi_i2c_set_scl(ctlr, 40, 87, HISI_I2C_SS_SCL_HCNT, HISI_I2C_SS_SCL_LCNT);
430 reg = readl(ctlr->iobase + HISI_I2C_FRAME_CTRL);
431 reg &= ~HISI_I2C_FRAME_CTRL_SPEED_MODE;
432 reg |= FIELD_PREP(HISI_I2C_FRAME_CTRL_SPEED_MODE, speed_mode);
433 writel(reg, ctlr->iobase + HISI_I2C_FRAME_CTRL);
435 sda_hold_cnt = NSEC_TO_CYCLES(ctlr->t.sda_hold_ns, ctlr->clk_rate_khz);
437 reg = FIELD_PREP(HISI_I2C_SDA_HOLD_TX, sda_hold_cnt);
438 writel(reg, ctlr->iobase + HISI_I2C_SDA_HOLD);
440 writel(ctlr->spk_len, ctlr->iobase + HISI_I2C_FS_SPK_LEN);
442 reg = FIELD_PREP(HISI_I2C_FIFO_RX_AF_THRESH, HISI_I2C_RX_F_AF_THRESH);
443 reg |= FIELD_PREP(HISI_I2C_FIFO_TX_AE_THRESH, HISI_I2C_TX_F_AE_THRESH);
444 writel(reg, ctlr->iobase + HISI_I2C_FIFO_CTRL);
447 static int hisi_i2c_probe(struct platform_device *pdev)
449 struct hisi_i2c_controller *ctlr;
450 struct device *dev = &pdev->dev;
451 struct i2c_adapter *adapter;
456 ctlr = devm_kzalloc(dev, sizeof(*ctlr), GFP_KERNEL);
460 ctlr->iobase = devm_platform_ioremap_resource(pdev, 0);
461 if (IS_ERR(ctlr->iobase))
462 return PTR_ERR(ctlr->iobase);
464 ctlr->irq = platform_get_irq(pdev, 0);
470 hisi_i2c_disable_int(ctlr, HISI_I2C_INT_ALL);
472 ret = devm_request_irq(dev, ctlr->irq, hisi_i2c_irq, 0, "hisi-i2c", ctlr);
474 dev_err(dev, "failed to request irq handler, ret = %d\n", ret);
478 ctlr->clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
479 if (IS_ERR_OR_NULL(ctlr->clk)) {
480 ret = device_property_read_u64(dev, "clk_rate", &clk_rate_hz);
482 dev_err(dev, "failed to get clock frequency, ret = %d\n", ret);
486 clk_rate_hz = clk_get_rate(ctlr->clk);
489 ctlr->clk_rate_khz = DIV_ROUND_UP_ULL(clk_rate_hz, HZ_PER_KHZ);
491 hisi_i2c_configure_bus(ctlr);
493 adapter = &ctlr->adapter;
494 snprintf(adapter->name, sizeof(adapter->name),
495 "HiSilicon I2C Controller %s", dev_name(dev));
496 adapter->owner = THIS_MODULE;
497 adapter->algo = &hisi_i2c_algo;
498 adapter->dev.parent = dev;
499 i2c_set_adapdata(adapter, ctlr);
501 ret = devm_i2c_add_adapter(dev, adapter);
505 hw_version = readl(ctlr->iobase + HISI_I2C_VERSION);
506 dev_info(ctlr->dev, "speed mode is %s. hw version 0x%x\n",
507 i2c_freq_mode_string(ctlr->t.bus_freq_hz), hw_version);
512 static const struct acpi_device_id hisi_i2c_acpi_ids[] = {
516 MODULE_DEVICE_TABLE(acpi, hisi_i2c_acpi_ids);
518 static const struct of_device_id hisi_i2c_dts_ids[] = {
519 { .compatible = "hisilicon,ascend910-i2c", },
522 MODULE_DEVICE_TABLE(of, hisi_i2c_dts_ids);
524 static struct platform_driver hisi_i2c_driver = {
525 .probe = hisi_i2c_probe,
528 .acpi_match_table = hisi_i2c_acpi_ids,
529 .of_match_table = hisi_i2c_dts_ids,
532 module_platform_driver(hisi_i2c_driver);
534 MODULE_AUTHOR("Yicong Yang <yangyicong@hisilicon.com>");
535 MODULE_DESCRIPTION("HiSilicon I2C Controller Driver");
536 MODULE_LICENSE("GPL");