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Moritz Fischerfdec2d22015-12-28 09:47:11 -08001/*
2 * Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
3 * IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
4 *
5 * This file is based on: drivers/i2c/zynq_i2c.c,
6 * with added driver-model support and code cleanup.
7 *
8 * SPDX-License-Identifier: GPL-2.0+
9 */
10
11#include <common.h>
12#include <linux/types.h>
13#include <linux/io.h>
14#include <asm/errno.h>
15#include <dm/device.h>
16#include <dm/root.h>
17#include <i2c.h>
18#include <fdtdec.h>
19#include <mapmem.h>
20
21DECLARE_GLOBAL_DATA_PTR;
22
23/* i2c register set */
24struct cdns_i2c_regs {
25 u32 control;
26 u32 status;
27 u32 address;
28 u32 data;
29 u32 interrupt_status;
30 u32 transfer_size;
31 u32 slave_mon_pause;
32 u32 time_out;
33 u32 interrupt_mask;
34 u32 interrupt_enable;
35 u32 interrupt_disable;
36};
37
38/* Control register fields */
39#define CDNS_I2C_CONTROL_RW 0x00000001
40#define CDNS_I2C_CONTROL_MS 0x00000002
41#define CDNS_I2C_CONTROL_NEA 0x00000004
42#define CDNS_I2C_CONTROL_ACKEN 0x00000008
43#define CDNS_I2C_CONTROL_HOLD 0x00000010
44#define CDNS_I2C_CONTROL_SLVMON 0x00000020
45#define CDNS_I2C_CONTROL_CLR_FIFO 0x00000040
46#define CDNS_I2C_CONTROL_DIV_B_SHIFT 8
47#define CDNS_I2C_CONTROL_DIV_B_MASK 0x00003F00
48#define CDNS_I2C_CONTROL_DIV_A_SHIFT 14
49#define CDNS_I2C_CONTROL_DIV_A_MASK 0x0000C000
50
51/* Status register values */
52#define CDNS_I2C_STATUS_RXDV 0x00000020
53#define CDNS_I2C_STATUS_TXDV 0x00000040
54#define CDNS_I2C_STATUS_RXOVF 0x00000080
55#define CDNS_I2C_STATUS_BA 0x00000100
56
57/* Interrupt register fields */
58#define CDNS_I2C_INTERRUPT_COMP 0x00000001
59#define CDNS_I2C_INTERRUPT_DATA 0x00000002
60#define CDNS_I2C_INTERRUPT_NACK 0x00000004
61#define CDNS_I2C_INTERRUPT_TO 0x00000008
62#define CDNS_I2C_INTERRUPT_SLVRDY 0x00000010
63#define CDNS_I2C_INTERRUPT_RXOVF 0x00000020
64#define CDNS_I2C_INTERRUPT_TXOVF 0x00000040
65#define CDNS_I2C_INTERRUPT_RXUNF 0x00000080
66#define CDNS_I2C_INTERRUPT_ARBLOST 0x00000200
67
68#define CDNS_I2C_FIFO_DEPTH 16
69#define CDNS_I2C_TRANSFER_SIZE_MAX 255 /* Controller transfer limit */
70
71#ifdef DEBUG
72static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
73{
74 int int_status;
75 int status;
76 int_status = readl(&cdns_i2c->interrupt_status);
77
78 status = readl(&cdns_i2c->status);
79 if (int_status || status) {
80 debug("Status: ");
81 if (int_status & CDNS_I2C_INTERRUPT_COMP)
82 debug("COMP ");
83 if (int_status & CDNS_I2C_INTERRUPT_DATA)
84 debug("DATA ");
85 if (int_status & CDNS_I2C_INTERRUPT_NACK)
86 debug("NACK ");
87 if (int_status & CDNS_I2C_INTERRUPT_TO)
88 debug("TO ");
89 if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
90 debug("SLVRDY ");
91 if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
92 debug("RXOVF ");
93 if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
94 debug("TXOVF ");
95 if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
96 debug("RXUNF ");
97 if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
98 debug("ARBLOST ");
99 if (status & CDNS_I2C_STATUS_RXDV)
100 debug("RXDV ");
101 if (status & CDNS_I2C_STATUS_TXDV)
102 debug("TXDV ");
103 if (status & CDNS_I2C_STATUS_RXOVF)
104 debug("RXOVF ");
105 if (status & CDNS_I2C_STATUS_BA)
106 debug("BA ");
107 debug("TS%d ", readl(&cdns_i2c->transfer_size));
108 debug("\n");
109 }
110}
111#endif
112
113struct i2c_cdns_bus {
114 int id;
Michal Simekad72e762016-04-14 14:15:49 +0200115 unsigned int input_freq;
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800116 struct cdns_i2c_regs __iomem *regs; /* register base */
117};
118
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800119/* Wait for an interrupt */
120static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
121{
122 int timeout, int_status;
123
124 for (timeout = 0; timeout < 100; timeout++) {
125 udelay(100);
126 int_status = readl(&cdns_i2c->interrupt_status);
127 if (int_status & mask)
128 break;
129 }
130
131 /* Clear interrupt status flags */
132 writel(int_status & mask, &cdns_i2c->interrupt_status);
133
134 return int_status & mask;
135}
136
Michal Simekad72e762016-04-14 14:15:49 +0200137#define CDNS_I2C_DIVA_MAX 4
138#define CDNS_I2C_DIVB_MAX 64
139
140static int cdns_i2c_calc_divs(unsigned long *f, unsigned long input_clk,
141 unsigned int *a, unsigned int *b)
142{
143 unsigned long fscl = *f, best_fscl = *f, actual_fscl, temp;
144 unsigned int div_a, div_b, calc_div_a = 0, calc_div_b = 0;
145 unsigned int last_error, current_error;
146
147 /* calculate (divisor_a+1) x (divisor_b+1) */
148 temp = input_clk / (22 * fscl);
149
150 /*
151 * If the calculated value is negative or 0CDNS_I2C_DIVA_MAX,
152 * the fscl input is out of range. Return error.
153 */
154 if (!temp || (temp > (CDNS_I2C_DIVA_MAX * CDNS_I2C_DIVB_MAX)))
155 return -EINVAL;
156
157 last_error = -1;
158 for (div_a = 0; div_a < CDNS_I2C_DIVA_MAX; div_a++) {
159 div_b = DIV_ROUND_UP(input_clk, 22 * fscl * (div_a + 1));
160
161 if ((div_b < 1) || (div_b > CDNS_I2C_DIVB_MAX))
162 continue;
163 div_b--;
164
165 actual_fscl = input_clk / (22 * (div_a + 1) * (div_b + 1));
166
167 if (actual_fscl > fscl)
168 continue;
169
170 current_error = ((actual_fscl > fscl) ? (actual_fscl - fscl) :
171 (fscl - actual_fscl));
172
173 if (last_error > current_error) {
174 calc_div_a = div_a;
175 calc_div_b = div_b;
176 best_fscl = actual_fscl;
177 last_error = current_error;
178 }
179 }
180
181 *a = calc_div_a;
182 *b = calc_div_b;
183 *f = best_fscl;
184
185 return 0;
186}
187
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800188static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
189{
Michal Simek6150be92016-04-14 14:15:48 +0200190 struct i2c_cdns_bus *bus = dev_get_priv(dev);
Michal Simekad72e762016-04-14 14:15:49 +0200191 u32 div_a = 0, div_b = 0;
192 unsigned long speed_p = speed;
193 int ret = 0;
Michal Simek6150be92016-04-14 14:15:48 +0200194
Michal Simekad72e762016-04-14 14:15:49 +0200195 if (speed > 400000) {
196 debug("%s, failed to set clock speed to %u\n", __func__,
197 speed);
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800198 return -EINVAL;
199 }
200
Michal Simekad72e762016-04-14 14:15:49 +0200201 ret = cdns_i2c_calc_divs(&speed_p, bus->input_freq, &div_a, &div_b);
202 if (ret)
203 return ret;
204
205 debug("%s: div_a: %d, div_b: %d, input freq: %d, speed: %d/%ld\n",
206 __func__, div_a, div_b, bus->input_freq, speed, speed_p);
207
208 writel((div_b << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
209 (div_a << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
Michal Simek6150be92016-04-14 14:15:48 +0200210
211 /* Enable master mode, ack, and 7-bit addressing */
212 setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
213 CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
214
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800215 return 0;
216}
217
218/* Probe to see if a chip is present. */
219static int cdns_i2c_probe_chip(struct udevice *bus, uint chip_addr,
220 uint chip_flags)
221{
222 struct i2c_cdns_bus *i2c_bus = dev_get_priv(bus);
223 struct cdns_i2c_regs *regs = i2c_bus->regs;
224
225 /* Attempt to read a byte */
226 setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
227 CDNS_I2C_CONTROL_RW);
228 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
229 writel(0xFF, &regs->interrupt_status);
230 writel(chip_addr, &regs->address);
231 writel(1, &regs->transfer_size);
232
233 return (cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
234 CDNS_I2C_INTERRUPT_NACK) &
235 CDNS_I2C_INTERRUPT_COMP) ? 0 : -ETIMEDOUT;
236}
237
238static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
239 u32 len, bool next_is_read)
240{
241 u8 *cur_data = data;
242
243 struct cdns_i2c_regs *regs = i2c_bus->regs;
244
245 setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
246 CDNS_I2C_CONTROL_HOLD);
247
248 /* if next is a read, we need to clear HOLD, doesn't work */
249 if (next_is_read)
250 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
251
252 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
253
254 writel(0xFF, &regs->interrupt_status);
255 writel(addr, &regs->address);
256
257 while (len--) {
258 writel(*(cur_data++), &regs->data);
259 if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
260 if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
261 /* Release the bus */
262 clrbits_le32(&regs->control,
263 CDNS_I2C_CONTROL_HOLD);
264 return -ETIMEDOUT;
265 }
266 }
267 }
268
269 /* All done... release the bus */
270 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
271 /* Wait for the address and data to be sent */
272 if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
273 return -ETIMEDOUT;
274 return 0;
275}
276
277static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
278 u32 len)
279{
280 u32 status;
281 u32 i = 0;
282 u8 *cur_data = data;
283
284 /* TODO: Fix this */
285 struct cdns_i2c_regs *regs = i2c_bus->regs;
286
287 /* Check the hardware can handle the requested bytes */
288 if ((len < 0) || (len > CDNS_I2C_TRANSFER_SIZE_MAX))
289 return -EINVAL;
290
291 setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
292 CDNS_I2C_CONTROL_RW);
293
294 /* Start reading data */
295 writel(addr, &regs->address);
296 writel(len, &regs->transfer_size);
297
298 /* Wait for data */
299 do {
300 status = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
301 CDNS_I2C_INTERRUPT_DATA);
302 if (!status) {
303 /* Release the bus */
304 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
305 return -ETIMEDOUT;
306 }
307 debug("Read %d bytes\n",
308 len - readl(&regs->transfer_size));
309 for (; i < len - readl(&regs->transfer_size); i++)
310 *(cur_data++) = readl(&regs->data);
311 } while (readl(&regs->transfer_size) != 0);
312 /* All done... release the bus */
313 clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
314
315#ifdef DEBUG
316 cdns_i2c_debug_status(regs);
317#endif
318 return 0;
319}
320
321static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
322 int nmsgs)
323{
324 struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
325 int ret;
326
327 debug("i2c_xfer: %d messages\n", nmsgs);
328 for (; nmsgs > 0; nmsgs--, msg++) {
329 bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
330
331 debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
332 if (msg->flags & I2C_M_RD) {
333 ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
334 msg->len);
335 } else {
336 ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
337 msg->len, next_is_read);
338 }
339 if (ret) {
340 debug("i2c_write: error sending\n");
341 return -EREMOTEIO;
342 }
343 }
344
345 return 0;
346}
347
Michal Simeka13767b2016-04-14 14:15:47 +0200348static int cdns_i2c_ofdata_to_platdata(struct udevice *dev)
349{
350 struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
351
352 i2c_bus->regs = (struct cdns_i2c_regs *)dev_get_addr(dev);
353 if (!i2c_bus->regs)
354 return -ENOMEM;
355
Michal Simekad72e762016-04-14 14:15:49 +0200356 i2c_bus->input_freq = 100000000; /* TODO hardcode input freq for now */
357
Michal Simeka13767b2016-04-14 14:15:47 +0200358 return 0;
359}
360
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800361static const struct dm_i2c_ops cdns_i2c_ops = {
362 .xfer = cdns_i2c_xfer,
363 .probe_chip = cdns_i2c_probe_chip,
364 .set_bus_speed = cdns_i2c_set_bus_speed,
365};
366
367static const struct udevice_id cdns_i2c_of_match[] = {
368 { .compatible = "cdns,i2c-r1p10" },
369 { /* end of table */ }
370};
371
372U_BOOT_DRIVER(cdns_i2c) = {
373 .name = "i2c-cdns",
374 .id = UCLASS_I2C,
375 .of_match = cdns_i2c_of_match,
Michal Simeka13767b2016-04-14 14:15:47 +0200376 .ofdata_to_platdata = cdns_i2c_ofdata_to_platdata,
Moritz Fischerfdec2d22015-12-28 09:47:11 -0800377 .priv_auto_alloc_size = sizeof(struct i2c_cdns_bus),
378 .ops = &cdns_i2c_ops,
379};