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Tom Rini83d290c2018-05-06 17:58:06 -04001// SPDX-License-Identifier: GPL-2.0+
Songjun Wu8800e0f2016-06-20 13:22:38 +08002/*
3 * Atmel I2C driver.
4 *
5 * (C) Copyright 2016 Songjun Wu <songjun.wu@atmel.com>
Songjun Wu8800e0f2016-06-20 13:22:38 +08006 */
7
Simon Glass336d4612020-02-03 07:36:16 -07008#include <malloc.h>
Songjun Wu8800e0f2016-06-20 13:22:38 +08009#include <asm/io.h>
10#include <common.h>
Wenyou Yang76062b92016-09-13 10:40:31 +080011#include <clk.h>
Songjun Wu8800e0f2016-06-20 13:22:38 +080012#include <dm.h>
13#include <errno.h>
14#include <fdtdec.h>
15#include <i2c.h>
16#include <linux/bitops.h>
17#include <mach/clk.h>
18
19#include "at91_i2c.h"
20
21DECLARE_GLOBAL_DATA_PTR;
22
23#define I2C_TIMEOUT_MS 100
24
25static int at91_wait_for_xfer(struct at91_i2c_bus *bus, u32 status)
26{
27 struct at91_i2c_regs *reg = bus->regs;
28 ulong start_time = get_timer(0);
29 u32 sr;
30
31 bus->status = 0;
32
33 do {
34 sr = readl(&reg->sr);
35 bus->status |= sr;
36
37 if (sr & TWI_SR_NACK)
38 return -EREMOTEIO;
39 else if (sr & status)
40 return 0;
41 } while (get_timer(start_time) < I2C_TIMEOUT_MS);
42
43 return -ETIMEDOUT;
44}
45
46static int at91_i2c_xfer_msg(struct at91_i2c_bus *bus, struct i2c_msg *msg)
47{
48 struct at91_i2c_regs *reg = bus->regs;
49 bool is_read = msg->flags & I2C_M_RD;
50 u32 i;
51 int ret = 0;
52
53 readl(&reg->sr);
54 if (is_read) {
55 writel(TWI_CR_START, &reg->cr);
56
57 for (i = 0; !ret && i < (msg->len - 1); i++) {
58 ret = at91_wait_for_xfer(bus, TWI_SR_RXRDY);
59 msg->buf[i] = readl(&reg->rhr);
60 }
61
62 if (ret)
63 goto error;
64
65 writel(TWI_CR_STOP, &reg->cr);
66
67 ret = at91_wait_for_xfer(bus, TWI_SR_RXRDY);
68 if (ret)
69 goto error;
70
71 msg->buf[i] = readl(&reg->rhr);
72
73 } else {
74 writel(msg->buf[0], &reg->thr);
Alan Ott0afbb0e2017-11-28 22:25:23 -050075 ret = at91_wait_for_xfer(bus, TWI_SR_TXRDY);
76
Songjun Wu8800e0f2016-06-20 13:22:38 +080077 for (i = 1; !ret && (i < msg->len); i++) {
78 writel(msg->buf[i], &reg->thr);
79 ret = at91_wait_for_xfer(bus, TWI_SR_TXRDY);
80 }
81
82 if (ret)
83 goto error;
84
85 writel(TWI_CR_STOP, &reg->cr);
86 }
87
88 if (!ret)
89 ret = at91_wait_for_xfer(bus, TWI_SR_TXCOMP);
90
91 if (ret)
92 goto error;
93
94 if (bus->status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_LOCK)) {
95 ret = -EIO;
96 goto error;
97 }
98
99 return 0;
100
101error:
102 if (bus->status & TWI_SR_LOCK)
103 writel(TWI_CR_LOCKCLR, &reg->cr);
104
105 return ret;
106}
107
108static int at91_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
109{
110 struct at91_i2c_bus *bus = dev_get_priv(dev);
111 struct at91_i2c_regs *reg = bus->regs;
112 struct i2c_msg *m_start = msg;
113 bool is_read;
114 u32 int_addr_flag = 0;
115 int ret = 0;
116
117 if (nmsgs == 2) {
118 int internal_address = 0;
119 int i;
120
121 /* 1st msg is put into the internal address, start with 2nd */
122 m_start = &msg[1];
123
124 /* the max length of internal address is 3 bytes */
125 if (msg->len > 3)
126 return -EFAULT;
127
128 for (i = 0; i < msg->len; ++i) {
129 const unsigned addr = msg->buf[msg->len - 1 - i];
130
131 internal_address |= addr << (8 * i);
132 int_addr_flag += TWI_MMR_IADRSZ_1;
133 }
134
135 writel(internal_address, &reg->iadr);
136 }
137
138 is_read = m_start->flags & I2C_M_RD;
139
140 writel((m_start->addr << 16) | int_addr_flag |
141 (is_read ? TWI_MMR_MREAD : 0), &reg->mmr);
142
143 ret = at91_i2c_xfer_msg(bus, m_start);
144
145 return ret;
146}
147
148/*
149 * Calculate symmetric clock as stated in datasheet:
150 * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
151 */
152static void at91_calc_i2c_clock(struct udevice *dev, int i2c_clk)
153{
154 struct at91_i2c_bus *bus = dev_get_priv(dev);
155 const struct at91_i2c_pdata *pdata = bus->pdata;
156 int offset = pdata->clk_offset;
157 int max_ckdiv = pdata->clk_max_div;
158 int ckdiv, cdiv, div;
159 unsigned long src_rate;
160
161 src_rate = bus->bus_clk_rate;
162
163 div = max(0, (int)DIV_ROUND_UP(src_rate, 2 * i2c_clk) - offset);
164 ckdiv = fls(div >> 8);
165 cdiv = div >> ckdiv;
166
167 if (ckdiv > max_ckdiv) {
168 ckdiv = max_ckdiv;
169 cdiv = 255;
170 }
171
172 bus->speed = DIV_ROUND_UP(src_rate,
173 (cdiv * (1 << ckdiv) + offset) * 2);
174
175 bus->cwgr_val = (ckdiv << 16) | (cdiv << 8) | cdiv;
176}
177
178static int at91_i2c_enable_clk(struct udevice *dev)
179{
180 struct at91_i2c_bus *bus = dev_get_priv(dev);
Songjun Wu8800e0f2016-06-20 13:22:38 +0800181 struct clk clk;
182 ulong clk_rate;
Songjun Wu8800e0f2016-06-20 13:22:38 +0800183 int ret;
184
185 ret = clk_get_by_index(dev, 0, &clk);
186 if (ret)
187 return -EINVAL;
188
Songjun Wu8800e0f2016-06-20 13:22:38 +0800189 ret = clk_enable(&clk);
190 if (ret)
191 return ret;
192
Songjun Wu8800e0f2016-06-20 13:22:38 +0800193 clk_rate = clk_get_rate(&clk);
194 if (!clk_rate)
Wenyou Yang52f37332016-09-27 11:00:32 +0800195 return -EINVAL;
Songjun Wu8800e0f2016-06-20 13:22:38 +0800196
197 bus->bus_clk_rate = clk_rate;
198
199 clk_free(&clk);
200
201 return 0;
202}
203
Songjun Wu8800e0f2016-06-20 13:22:38 +0800204static int at91_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
205{
206 struct at91_i2c_bus *bus = dev_get_priv(dev);
207
208 at91_calc_i2c_clock(dev, speed);
209
210 writel(bus->cwgr_val, &bus->regs->cwgr);
211
212 return 0;
213}
214
215int at91_i2c_get_bus_speed(struct udevice *dev)
216{
217 struct at91_i2c_bus *bus = dev_get_priv(dev);
218
219 return bus->speed;
220}
221
222static int at91_i2c_ofdata_to_platdata(struct udevice *dev)
223{
224 const void *blob = gd->fdt_blob;
225 struct at91_i2c_bus *bus = dev_get_priv(dev);
Simon Glasse160f7d2017-01-17 16:52:55 -0700226 int node = dev_of_offset(dev);
Songjun Wu8800e0f2016-06-20 13:22:38 +0800227
Simon Glassa821c4a2017-05-17 17:18:05 -0600228 bus->regs = (struct at91_i2c_regs *)devfdt_get_addr(dev);
Songjun Wu8800e0f2016-06-20 13:22:38 +0800229 bus->pdata = (struct at91_i2c_pdata *)dev_get_driver_data(dev);
230 bus->clock_frequency = fdtdec_get_int(blob, node,
231 "clock-frequency", 100000);
232
233 return 0;
234}
235
236static const struct dm_i2c_ops at91_i2c_ops = {
237 .xfer = at91_i2c_xfer,
Songjun Wu8800e0f2016-06-20 13:22:38 +0800238 .set_bus_speed = at91_i2c_set_bus_speed,
239 .get_bus_speed = at91_i2c_get_bus_speed,
240};
241
Wenyou.Yang@microchip.com0bc8f642017-07-31 09:56:27 +0800242static int at91_i2c_probe(struct udevice *dev)
243{
244 struct at91_i2c_bus *bus = dev_get_priv(dev);
245 struct at91_i2c_regs *reg = bus->regs;
246 int ret;
247
248 ret = at91_i2c_enable_clk(dev);
249 if (ret)
250 return ret;
251
252 writel(TWI_CR_SWRST, &reg->cr);
253
254 at91_calc_i2c_clock(dev, bus->clock_frequency);
255
256 writel(bus->cwgr_val, &reg->cwgr);
257 writel(TWI_CR_MSEN, &reg->cr);
258 writel(TWI_CR_SVDIS, &reg->cr);
259
260 return 0;
261}
262
Songjun Wu8800e0f2016-06-20 13:22:38 +0800263static const struct at91_i2c_pdata at91rm9200_config = {
264 .clk_max_div = 5,
265 .clk_offset = 3,
266};
267
268static const struct at91_i2c_pdata at91sam9261_config = {
269 .clk_max_div = 5,
270 .clk_offset = 4,
271};
272
273static const struct at91_i2c_pdata at91sam9260_config = {
274 .clk_max_div = 7,
275 .clk_offset = 4,
276};
277
278static const struct at91_i2c_pdata at91sam9g20_config = {
279 .clk_max_div = 7,
280 .clk_offset = 4,
281};
282
283static const struct at91_i2c_pdata at91sam9g10_config = {
284 .clk_max_div = 7,
285 .clk_offset = 4,
286};
287
288static const struct at91_i2c_pdata at91sam9x5_config = {
289 .clk_max_div = 7,
290 .clk_offset = 4,
291};
292
293static const struct at91_i2c_pdata sama5d4_config = {
294 .clk_max_div = 7,
295 .clk_offset = 4,
296};
297
298static const struct at91_i2c_pdata sama5d2_config = {
299 .clk_max_div = 7,
300 .clk_offset = 3,
301};
302
303static const struct udevice_id at91_i2c_ids[] = {
304{ .compatible = "atmel,at91rm9200-i2c", .data = (long)&at91rm9200_config },
305{ .compatible = "atmel,at91sam9260-i2c", .data = (long)&at91sam9260_config },
306{ .compatible = "atmel,at91sam9261-i2c", .data = (long)&at91sam9261_config },
307{ .compatible = "atmel,at91sam9g20-i2c", .data = (long)&at91sam9g20_config },
308{ .compatible = "atmel,at91sam9g10-i2c", .data = (long)&at91sam9g10_config },
309{ .compatible = "atmel,at91sam9x5-i2c", .data = (long)&at91sam9x5_config },
310{ .compatible = "atmel,sama5d4-i2c", .data = (long)&sama5d4_config },
311{ .compatible = "atmel,sama5d2-i2c", .data = (long)&sama5d2_config },
312{ }
313};
314
315U_BOOT_DRIVER(i2c_at91) = {
316 .name = "i2c_at91",
317 .id = UCLASS_I2C,
318 .of_match = at91_i2c_ids,
Wenyou.Yang@microchip.com0bc8f642017-07-31 09:56:27 +0800319 .probe = at91_i2c_probe,
Songjun Wu8800e0f2016-06-20 13:22:38 +0800320 .ofdata_to_platdata = at91_i2c_ofdata_to_platdata,
321 .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
322 .priv_auto_alloc_size = sizeof(struct at91_i2c_bus),
323 .ops = &at91_i2c_ops,
324};