1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * netup_unidvb_i2c.c
4 *
5 * Internal I2C bus driver for NetUP Universal Dual DVB-CI
6 *
7 * Copyright (C) 2014 NetUP Inc.
8 * Copyright (C) 2014 Sergey Kozlov <serjk@netup.ru>
9 * Copyright (C) 2014 Abylay Ospan <aospan@netup.ru>
10 */
11
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/init.h>
15 #include <linux/delay.h>
16 #include "netup_unidvb.h"
17
18 #define NETUP_I2C_BUS0_ADDR 0x4800
19 #define NETUP_I2C_BUS1_ADDR 0x4840
20 #define NETUP_I2C_TIMEOUT 1000
21
22 /* twi_ctrl0_stat reg bits */
23 #define TWI_IRQEN_COMPL 0x1
24 #define TWI_IRQEN_ANACK 0x2
25 #define TWI_IRQEN_DNACK 0x4
26 #define TWI_IRQ_COMPL (TWI_IRQEN_COMPL << 8)
27 #define TWI_IRQ_ANACK (TWI_IRQEN_ANACK << 8)
28 #define TWI_IRQ_DNACK (TWI_IRQEN_DNACK << 8)
29 #define TWI_IRQ_TX 0x800
30 #define TWI_IRQ_RX 0x1000
31 #define TWI_IRQEN (TWI_IRQEN_COMPL | TWI_IRQEN_ANACK | TWI_IRQEN_DNACK)
32 /* twi_addr_ctrl1 reg bits*/
33 #define TWI_TRANSFER 0x100
34 #define TWI_NOSTOP 0x200
35 #define TWI_SOFT_RESET 0x2000
36 /* twi_clkdiv reg value */
37 #define TWI_CLKDIV 156
38 /* fifo_stat_ctrl reg bits */
39 #define FIFO_IRQEN 0x8000
40 #define FIFO_RESET 0x4000
41 /* FIFO size */
42 #define FIFO_SIZE 16
43
44 struct netup_i2c_fifo_regs {
45 union {
46 __u8 data8;
47 __le16 data16;
48 __le32 data32;
49 };
50 __u8 padding[4];
51 __le16 stat_ctrl;
52 } __packed __aligned(1);
53
54 struct netup_i2c_regs {
55 __le16 clkdiv;
56 __le16 twi_ctrl0_stat;
57 __le16 twi_addr_ctrl1;
58 __le16 length;
59 __u8 padding1[8];
60 struct netup_i2c_fifo_regs tx_fifo;
61 __u8 padding2[6];
62 struct netup_i2c_fifo_regs rx_fifo;
63 } __packed __aligned(1);
64
netup_i2c_interrupt(struct netup_i2c * i2c)65 irqreturn_t netup_i2c_interrupt(struct netup_i2c *i2c)
66 {
67 u16 reg, tmp;
68 unsigned long flags;
69 irqreturn_t iret = IRQ_HANDLED;
70
71 spin_lock_irqsave(&i2c->lock, flags);
72 reg = readw(&i2c->regs->twi_ctrl0_stat);
73 writew(reg & ~TWI_IRQEN, &i2c->regs->twi_ctrl0_stat);
74 dev_dbg(i2c->adap.dev.parent,
75 "%s(): twi_ctrl0_state 0x%x\n", __func__, reg);
76 if ((reg & TWI_IRQEN_COMPL) != 0 && (reg & TWI_IRQ_COMPL)) {
77 dev_dbg(i2c->adap.dev.parent,
78 "%s(): TWI_IRQEN_COMPL\n", __func__);
79 i2c->state = STATE_DONE;
80 goto irq_ok;
81 }
82 if ((reg & TWI_IRQEN_ANACK) != 0 && (reg & TWI_IRQ_ANACK)) {
83 dev_dbg(i2c->adap.dev.parent,
84 "%s(): TWI_IRQEN_ANACK\n", __func__);
85 i2c->state = STATE_ERROR;
86 goto irq_ok;
87 }
88 if ((reg & TWI_IRQEN_DNACK) != 0 && (reg & TWI_IRQ_DNACK)) {
89 dev_dbg(i2c->adap.dev.parent,
90 "%s(): TWI_IRQEN_DNACK\n", __func__);
91 i2c->state = STATE_ERROR;
92 goto irq_ok;
93 }
94 if ((reg & TWI_IRQ_RX) != 0) {
95 tmp = readw(&i2c->regs->rx_fifo.stat_ctrl);
96 writew(tmp & ~FIFO_IRQEN, &i2c->regs->rx_fifo.stat_ctrl);
97 i2c->state = STATE_WANT_READ;
98 dev_dbg(i2c->adap.dev.parent,
99 "%s(): want read\n", __func__);
100 goto irq_ok;
101 }
102 if ((reg & TWI_IRQ_TX) != 0) {
103 tmp = readw(&i2c->regs->tx_fifo.stat_ctrl);
104 writew(tmp & ~FIFO_IRQEN, &i2c->regs->tx_fifo.stat_ctrl);
105 i2c->state = STATE_WANT_WRITE;
106 dev_dbg(i2c->adap.dev.parent,
107 "%s(): want write\n", __func__);
108 goto irq_ok;
109 }
110 dev_warn(&i2c->adap.dev, "%s(): not mine interrupt\n", __func__);
111 iret = IRQ_NONE;
112 irq_ok:
113 spin_unlock_irqrestore(&i2c->lock, flags);
114 if (iret == IRQ_HANDLED)
115 wake_up(&i2c->wq);
116 return iret;
117 }
118
netup_i2c_reset(struct netup_i2c * i2c)119 static void netup_i2c_reset(struct netup_i2c *i2c)
120 {
121 dev_dbg(i2c->adap.dev.parent, "%s()\n", __func__);
122 i2c->state = STATE_DONE;
123 writew(TWI_SOFT_RESET, &i2c->regs->twi_addr_ctrl1);
124 writew(TWI_CLKDIV, &i2c->regs->clkdiv);
125 writew(FIFO_RESET, &i2c->regs->tx_fifo.stat_ctrl);
126 writew(FIFO_RESET, &i2c->regs->rx_fifo.stat_ctrl);
127 writew(0x800, &i2c->regs->tx_fifo.stat_ctrl);
128 writew(0x800, &i2c->regs->rx_fifo.stat_ctrl);
129 }
130
netup_i2c_fifo_tx(struct netup_i2c * i2c)131 static void netup_i2c_fifo_tx(struct netup_i2c *i2c)
132 {
133 u8 data;
134 u32 fifo_space = FIFO_SIZE -
135 (readw(&i2c->regs->tx_fifo.stat_ctrl) & 0x3f);
136 u32 msg_length = i2c->msg->len - i2c->xmit_size;
137
138 msg_length = (msg_length < fifo_space ? msg_length : fifo_space);
139 while (msg_length--) {
140 data = i2c->msg->buf[i2c->xmit_size++];
141 writeb(data, &i2c->regs->tx_fifo.data8);
142 dev_dbg(i2c->adap.dev.parent,
143 "%s(): write 0x%02x\n", __func__, data);
144 }
145 if (i2c->xmit_size < i2c->msg->len) {
146 dev_dbg(i2c->adap.dev.parent,
147 "%s(): TX IRQ enabled\n", __func__);
148 writew(readw(&i2c->regs->tx_fifo.stat_ctrl) | FIFO_IRQEN,
149 &i2c->regs->tx_fifo.stat_ctrl);
150 }
151 }
152
netup_i2c_fifo_rx(struct netup_i2c * i2c)153 static void netup_i2c_fifo_rx(struct netup_i2c *i2c)
154 {
155 u8 data;
156 u32 fifo_size = readw(&i2c->regs->rx_fifo.stat_ctrl) & 0x3f;
157
158 dev_dbg(i2c->adap.dev.parent,
159 "%s(): RX fifo size %d\n", __func__, fifo_size);
160 while (fifo_size--) {
161 data = readb(&i2c->regs->rx_fifo.data8);
162 if ((i2c->msg->flags & I2C_M_RD) != 0 &&
163 i2c->xmit_size < i2c->msg->len) {
164 i2c->msg->buf[i2c->xmit_size++] = data;
165 dev_dbg(i2c->adap.dev.parent,
166 "%s(): read 0x%02x\n", __func__, data);
167 }
168 }
169 if (i2c->xmit_size < i2c->msg->len) {
170 dev_dbg(i2c->adap.dev.parent,
171 "%s(): RX IRQ enabled\n", __func__);
172 writew(readw(&i2c->regs->rx_fifo.stat_ctrl) | FIFO_IRQEN,
173 &i2c->regs->rx_fifo.stat_ctrl);
174 }
175 }
176
netup_i2c_start_xfer(struct netup_i2c * i2c)177 static void netup_i2c_start_xfer(struct netup_i2c *i2c)
178 {
179 u16 rdflag = ((i2c->msg->flags & I2C_M_RD) ? 1 : 0);
180 u16 reg = readw(&i2c->regs->twi_ctrl0_stat);
181
182 writew(TWI_IRQEN | reg, &i2c->regs->twi_ctrl0_stat);
183 writew(i2c->msg->len, &i2c->regs->length);
184 writew(TWI_TRANSFER | (i2c->msg->addr << 1) | rdflag,
185 &i2c->regs->twi_addr_ctrl1);
186 dev_dbg(i2c->adap.dev.parent,
187 "%s(): length %d twi_addr_ctrl1 0x%x twi_ctrl0_stat 0x%x\n",
188 __func__, readw(&i2c->regs->length),
189 readw(&i2c->regs->twi_addr_ctrl1),
190 readw(&i2c->regs->twi_ctrl0_stat));
191 i2c->state = STATE_WAIT;
192 i2c->xmit_size = 0;
193 if (!rdflag)
194 netup_i2c_fifo_tx(i2c);
195 else
196 writew(FIFO_IRQEN | readw(&i2c->regs->rx_fifo.stat_ctrl),
197 &i2c->regs->rx_fifo.stat_ctrl);
198 }
199
netup_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)200 static int netup_i2c_xfer(struct i2c_adapter *adap,
201 struct i2c_msg *msgs, int num)
202 {
203 unsigned long flags;
204 int i, trans_done, res = num;
205 struct netup_i2c *i2c = i2c_get_adapdata(adap);
206 u16 reg;
207
208 spin_lock_irqsave(&i2c->lock, flags);
209 if (i2c->state != STATE_DONE) {
210 dev_dbg(i2c->adap.dev.parent,
211 "%s(): i2c->state == %d, resetting I2C\n",
212 __func__, i2c->state);
213 netup_i2c_reset(i2c);
214 }
215 dev_dbg(i2c->adap.dev.parent, "%s() num %d\n", __func__, num);
216 for (i = 0; i < num; i++) {
217 i2c->msg = &msgs[i];
218 netup_i2c_start_xfer(i2c);
219 trans_done = 0;
220 while (!trans_done) {
221 spin_unlock_irqrestore(&i2c->lock, flags);
222 if (wait_event_timeout(i2c->wq,
223 i2c->state != STATE_WAIT,
224 msecs_to_jiffies(NETUP_I2C_TIMEOUT))) {
225 spin_lock_irqsave(&i2c->lock, flags);
226 switch (i2c->state) {
227 case STATE_WANT_READ:
228 netup_i2c_fifo_rx(i2c);
229 break;
230 case STATE_WANT_WRITE:
231 netup_i2c_fifo_tx(i2c);
232 break;
233 case STATE_DONE:
234 if ((i2c->msg->flags & I2C_M_RD) != 0 &&
235 i2c->xmit_size != i2c->msg->len)
236 netup_i2c_fifo_rx(i2c);
237 dev_dbg(i2c->adap.dev.parent,
238 "%s(): msg %d OK\n",
239 __func__, i);
240 trans_done = 1;
241 break;
242 case STATE_ERROR:
243 res = -EIO;
244 dev_dbg(i2c->adap.dev.parent,
245 "%s(): error state\n",
246 __func__);
247 goto done;
248 default:
249 dev_dbg(i2c->adap.dev.parent,
250 "%s(): invalid state %d\n",
251 __func__, i2c->state);
252 res = -EINVAL;
253 goto done;
254 }
255 if (!trans_done) {
256 i2c->state = STATE_WAIT;
257 reg = readw(
258 &i2c->regs->twi_ctrl0_stat);
259 writew(TWI_IRQEN | reg,
260 &i2c->regs->twi_ctrl0_stat);
261 }
262 spin_unlock_irqrestore(&i2c->lock, flags);
263 } else {
264 spin_lock_irqsave(&i2c->lock, flags);
265 dev_dbg(i2c->adap.dev.parent,
266 "%s(): wait timeout\n", __func__);
267 res = -ETIMEDOUT;
268 goto done;
269 }
270 spin_lock_irqsave(&i2c->lock, flags);
271 }
272 }
273 done:
274 spin_unlock_irqrestore(&i2c->lock, flags);
275 dev_dbg(i2c->adap.dev.parent, "%s(): result %d\n", __func__, res);
276 return res;
277 }
278
netup_i2c_func(struct i2c_adapter * adap)279 static u32 netup_i2c_func(struct i2c_adapter *adap)
280 {
281 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
282 }
283
284 static const struct i2c_algorithm netup_i2c_algorithm = {
285 .master_xfer = netup_i2c_xfer,
286 .functionality = netup_i2c_func,
287 };
288
289 static const struct i2c_adapter netup_i2c_adapter = {
290 .owner = THIS_MODULE,
291 .name = NETUP_UNIDVB_NAME,
292 .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
293 .algo = &netup_i2c_algorithm,
294 };
295
netup_i2c_init(struct netup_unidvb_dev * ndev,int bus_num)296 static int netup_i2c_init(struct netup_unidvb_dev *ndev, int bus_num)
297 {
298 int ret;
299 struct netup_i2c *i2c;
300
301 if (bus_num < 0 || bus_num > 1) {
302 dev_err(&ndev->pci_dev->dev,
303 "%s(): invalid bus_num %d\n", __func__, bus_num);
304 return -EINVAL;
305 }
306 i2c = &ndev->i2c[bus_num];
307 spin_lock_init(&i2c->lock);
308 init_waitqueue_head(&i2c->wq);
309 i2c->regs = (struct netup_i2c_regs __iomem *)(ndev->bmmio0 +
310 (bus_num == 0 ? NETUP_I2C_BUS0_ADDR : NETUP_I2C_BUS1_ADDR));
311 netup_i2c_reset(i2c);
312 i2c->adap = netup_i2c_adapter;
313 i2c->adap.dev.parent = &ndev->pci_dev->dev;
314 i2c_set_adapdata(&i2c->adap, i2c);
315 ret = i2c_add_adapter(&i2c->adap);
316 if (ret)
317 return ret;
318 dev_info(&ndev->pci_dev->dev,
319 "%s(): registered I2C bus %d at 0x%x\n",
320 __func__,
321 bus_num, (bus_num == 0 ?
322 NETUP_I2C_BUS0_ADDR :
323 NETUP_I2C_BUS1_ADDR));
324 return 0;
325 }
326
netup_i2c_remove(struct netup_unidvb_dev * ndev,int bus_num)327 static void netup_i2c_remove(struct netup_unidvb_dev *ndev, int bus_num)
328 {
329 struct netup_i2c *i2c;
330
331 if (bus_num < 0 || bus_num > 1) {
332 dev_err(&ndev->pci_dev->dev,
333 "%s(): invalid bus number %d\n", __func__, bus_num);
334 return;
335 }
336 i2c = &ndev->i2c[bus_num];
337 netup_i2c_reset(i2c);
338 /* remove adapter */
339 i2c_del_adapter(&i2c->adap);
340 dev_info(&ndev->pci_dev->dev,
341 "netup_i2c_remove: unregistered I2C bus %d\n", bus_num);
342 }
343
netup_i2c_register(struct netup_unidvb_dev * ndev)344 int netup_i2c_register(struct netup_unidvb_dev *ndev)
345 {
346 int ret;
347
348 ret = netup_i2c_init(ndev, 0);
349 if (ret)
350 return ret;
351 ret = netup_i2c_init(ndev, 1);
352 if (ret) {
353 netup_i2c_remove(ndev, 0);
354 return ret;
355 }
356 return 0;
357 }
358
netup_i2c_unregister(struct netup_unidvb_dev * ndev)359 void netup_i2c_unregister(struct netup_unidvb_dev *ndev)
360 {
361 netup_i2c_remove(ndev, 0);
362 netup_i2c_remove(ndev, 1);
363 }
364
365