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Merge branch 'master' of git://www.denx.de/git/u-boot-imx
[people/ms/u-boot.git] / drivers / i2c / i2c-uniphier-f.c
CommitLineData
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1/*
2 * Copyright (C) 2014 Panasonic Corporation
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3 * Copyright (C) 2015 Socionext Inc.
4 * Author: Masahiro Yamada <yamada.masahiro@socionext.com>
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5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
9#include <common.h>
10#include <linux/types.h>
11#include <asm/io.h>
12#include <asm/errno.h>
13#include <dm/device.h>
14#include <dm/root.h>
15#include <i2c.h>
16#include <fdtdec.h>
17
18DECLARE_GLOBAL_DATA_PTR;
19
20struct uniphier_fi2c_regs {
21 u32 cr; /* control register */
22#define I2C_CR_MST (1 << 3) /* master mode */
23#define I2C_CR_STA (1 << 2) /* start condition */
24#define I2C_CR_STO (1 << 1) /* stop condition */
25#define I2C_CR_NACK (1 << 0) /* not ACK */
26 u32 dttx; /* send FIFO (write-only) */
27#define dtrx dttx /* receive FIFO (read-only) */
28#define I2C_DTTX_CMD (1 << 8) /* send command (slave addr) */
29#define I2C_DTTX_RD (1 << 0) /* read */
30 u32 __reserved; /* no register at offset 0x08 */
31 u32 slad; /* slave address */
32 u32 cyc; /* clock cycle control */
33 u32 lctl; /* clock low period control */
34 u32 ssut; /* restart/stop setup time control */
35 u32 dsut; /* data setup time control */
36 u32 intr; /* interrupt status */
37 u32 ie; /* interrupt enable */
38 u32 ic; /* interrupt clear */
39#define I2C_INT_TE (1 << 9) /* TX FIFO empty */
40#define I2C_INT_RB (1 << 4) /* received specified bytes */
41#define I2C_INT_NA (1 << 2) /* no answer */
42#define I2C_INT_AL (1 << 1) /* arbitration lost */
43 u32 sr; /* status register */
44#define I2C_SR_DB (1 << 12) /* device busy */
45#define I2C_SR_BB (1 << 8) /* bus busy */
46#define I2C_SR_RFF (1 << 3) /* Rx FIFO full */
47#define I2C_SR_RNE (1 << 2) /* Rx FIFO not empty */
48#define I2C_SR_TNF (1 << 1) /* Tx FIFO not full */
49#define I2C_SR_TFE (1 << 0) /* Tx FIFO empty */
50 u32 __reserved2; /* no register at offset 0x30 */
51 u32 rst; /* reset control */
52#define I2C_RST_TBRST (1 << 2) /* clear Tx FIFO */
53#define I2C_RST_RBRST (1 << 1) /* clear Rx FIFO */
54#define I2C_RST_RST (1 << 0) /* forcible bus reset */
55 u32 bm; /* bus monitor */
56 u32 noise; /* noise filter control */
57 u32 tbc; /* Tx byte count setting */
58 u32 rbc; /* Rx byte count setting */
59 u32 tbcm; /* Tx byte count monitor */
60 u32 rbcm; /* Rx byte count monitor */
61 u32 brst; /* bus reset */
62#define I2C_BRST_FOEN (1 << 1) /* normal operation */
63#define I2C_BRST_RSCLO (1 << 0) /* release SCL low fixing */
64};
65
66#define FIOCLK 50000000
67
68struct uniphier_fi2c_dev {
69 struct uniphier_fi2c_regs __iomem *regs; /* register base */
70 unsigned long fioclk; /* internal operation clock */
71 unsigned long timeout; /* time out (us) */
72};
73
74static int poll_status(u32 __iomem *reg, u32 flag)
75{
76 int wait = 1000000; /* 1 sec is long enough */
77
78 while (readl(reg) & flag) {
79 if (wait-- < 0)
80 return -EREMOTEIO;
81 udelay(1);
82 }
83
84 return 0;
85}
86
87static int reset_bus(struct uniphier_fi2c_regs __iomem *regs)
88{
89 int ret;
90
91 /* bus forcible reset */
92 writel(I2C_RST_RST, &regs->rst);
93 ret = poll_status(&regs->rst, I2C_RST_RST);
94 if (ret < 0)
95 debug("error: fail to reset I2C controller\n");
96
97 return ret;
98}
99
100static int check_device_busy(struct uniphier_fi2c_regs __iomem *regs)
101{
102 int ret;
103
104 ret = poll_status(&regs->sr, I2C_SR_DB);
105 if (ret < 0) {
106 debug("error: device busy too long. reset...\n");
107 ret = reset_bus(regs);
108 }
109
110 return ret;
111}
112
113static int uniphier_fi2c_probe(struct udevice *dev)
114{
115 fdt_addr_t addr;
116 fdt_size_t size;
117 struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
118 int ret;
119
120 addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg",
121 &size);
122
123 priv->regs = map_sysmem(addr, size);
124
125 if (!priv->regs)
126 return -ENOMEM;
127
128 priv->fioclk = FIOCLK;
129
130 /* bus forcible reset */
131 ret = reset_bus(priv->regs);
132 if (ret < 0)
133 return ret;
134
135 writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &priv->regs->brst);
136
137 return 0;
138}
139
140static int uniphier_fi2c_remove(struct udevice *dev)
141{
142 struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
143
144 unmap_sysmem(priv->regs);
145
146 return 0;
147}
148
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149static int wait_for_irq(struct uniphier_fi2c_dev *dev, u32 flags,
150 bool *stop)
151{
152 u32 irq;
153 unsigned long wait = dev->timeout;
154 int ret = -EREMOTEIO;
155
156 do {
157 udelay(1);
158 irq = readl(&dev->regs->intr);
159 } while (!(irq & flags) && wait--);
160
161 if (wait < 0) {
162 debug("error: time out\n");
163 return ret;
164 }
165
166 if (irq & I2C_INT_AL) {
167 debug("error: arbitration lost\n");
168 *stop = false;
169 return ret;
170 }
171
172 if (irq & I2C_INT_NA) {
173 debug("error: no answer\n");
174 return ret;
175 }
176
177 return 0;
178}
179
180static int issue_stop(struct uniphier_fi2c_dev *dev, int old_ret)
181{
182 int ret;
183
184 debug("stop condition\n");
185 writel(I2C_CR_MST | I2C_CR_STO, &dev->regs->cr);
186
187 ret = poll_status(&dev->regs->sr, I2C_SR_DB);
188 if (ret < 0)
189 debug("error: device busy after operation\n");
190
191 return old_ret ? old_ret : ret;
192}
193
194static int uniphier_fi2c_transmit(struct uniphier_fi2c_dev *dev, uint addr,
195 uint len, const u8 *buf, bool *stop)
196{
197 int ret;
198 const u32 irq_flags = I2C_INT_TE | I2C_INT_NA | I2C_INT_AL;
199 struct uniphier_fi2c_regs __iomem *regs = dev->regs;
200
201 debug("%s: addr = %x, len = %d\n", __func__, addr, len);
202
203 writel(I2C_DTTX_CMD | addr << 1, &regs->dttx);
204
205 writel(irq_flags, &regs->ie);
206 writel(irq_flags, &regs->ic);
207
208 debug("start condition\n");
209 writel(I2C_CR_MST | I2C_CR_STA, &regs->cr);
210
211 ret = wait_for_irq(dev, irq_flags, stop);
212 if (ret < 0)
213 goto error;
214
215 while (len--) {
216 debug("sending %x\n", *buf);
217 writel(*buf++, &regs->dttx);
218
219 writel(irq_flags, &regs->ic);
220
221 ret = wait_for_irq(dev, irq_flags, stop);
222 if (ret < 0)
223 goto error;
224 }
225
226error:
227 writel(irq_flags, &regs->ic);
228
229 if (*stop)
230 ret = issue_stop(dev, ret);
231
232 return ret;
233}
234
235static int uniphier_fi2c_receive(struct uniphier_fi2c_dev *dev, uint addr,
236 uint len, u8 *buf, bool *stop)
237{
238 int ret = 0;
239 const u32 irq_flags = I2C_INT_RB | I2C_INT_NA | I2C_INT_AL;
240 struct uniphier_fi2c_regs __iomem *regs = dev->regs;
241
242 debug("%s: addr = %x, len = %d\n", __func__, addr, len);
243
244 /*
245 * In case 'len == 0', only the slave address should be sent
246 * for probing, which is covered by the transmit function.
247 */
248 if (len == 0)
249 return uniphier_fi2c_transmit(dev, addr, len, buf, stop);
250
251 writel(I2C_DTTX_CMD | I2C_DTTX_RD | addr << 1, &regs->dttx);
252
253 writel(0, &regs->rbc);
254 writel(irq_flags, &regs->ie);
255 writel(irq_flags, &regs->ic);
256
257 debug("start condition\n");
258 writel(I2C_CR_MST | I2C_CR_STA | (len == 1 ? I2C_CR_NACK : 0),
259 &regs->cr);
260
261 while (len--) {
262 ret = wait_for_irq(dev, irq_flags, stop);
263 if (ret < 0)
264 goto error;
265
266 *buf++ = readl(&regs->dtrx);
267 debug("received %x\n", *(buf - 1));
268
269 if (len == 1)
270 writel(I2C_CR_MST | I2C_CR_NACK, &regs->cr);
271
272 writel(irq_flags, &regs->ic);
273 }
274
275error:
276 writel(irq_flags, &regs->ic);
277
278 if (*stop)
279 ret = issue_stop(dev, ret);
280
281 return ret;
282}
283
284static int uniphier_fi2c_xfer(struct udevice *bus, struct i2c_msg *msg,
285 int nmsgs)
286{
287 int ret;
288 struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
289 bool stop;
290
291 ret = check_device_busy(dev->regs);
292 if (ret < 0)
293 return ret;
294
295 for (; nmsgs > 0; nmsgs--, msg++) {
296 /* If next message is read, skip the stop condition */
297 stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
298
299 if (msg->flags & I2C_M_RD)
300 ret = uniphier_fi2c_receive(dev, msg->addr, msg->len,
301 msg->buf, &stop);
302 else
303 ret = uniphier_fi2c_transmit(dev, msg->addr, msg->len,
304 msg->buf, &stop);
305
306 if (ret < 0)
307 break;
308 }
309
310 return ret;
311}
312
313static int uniphier_fi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
314{
315 int ret;
316 unsigned int clk_count;
317 struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
318 struct uniphier_fi2c_regs __iomem *regs = dev->regs;
319
320 /* max supported frequency is 400 kHz */
321 if (speed > 400000)
322 return -EINVAL;
323
324 ret = check_device_busy(dev->regs);
325 if (ret < 0)
326 return ret;
327
328 /* make sure the bus is idle when changing the frequency */
329 writel(I2C_BRST_RSCLO, &regs->brst);
330
331 clk_count = dev->fioclk / speed;
332
333 writel(clk_count, &regs->cyc);
334 writel(clk_count / 2, &regs->lctl);
335 writel(clk_count / 2, &regs->ssut);
336 writel(clk_count / 16, &regs->dsut);
337
338 writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &regs->brst);
339
340 /*
341 * Theoretically, each byte can be transferred in
342 * 1000000 * 9 / speed usec.
343 * This time out value is long enough.
344 */
345 dev->timeout = 100000000L / speed;
346
347 return 0;
348}
349
350static const struct dm_i2c_ops uniphier_fi2c_ops = {
351 .xfer = uniphier_fi2c_xfer,
352 .set_bus_speed = uniphier_fi2c_set_bus_speed,
353};
354
355static const struct udevice_id uniphier_fi2c_of_match[] = {
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356 { .compatible = "socionext,uniphier-fi2c" },
357 { /* sentinel */ }
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358};
359
360U_BOOT_DRIVER(uniphier_fi2c) = {
361 .name = "uniphier-fi2c",
362 .id = UCLASS_I2C,
363 .of_match = uniphier_fi2c_of_match,
364 .probe = uniphier_fi2c_probe,
365 .remove = uniphier_fi2c_remove,
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366 .priv_auto_alloc_size = sizeof(struct uniphier_fi2c_dev),
367 .ops = &uniphier_fi2c_ops,
368};