1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Linux driver for digital TV devices equipped with B2C2 FlexcopII(b)/III
4  * flexcop-i2c.c - flexcop internal 2Wire bus (I2C) and dvb i2c initialization
5  * see flexcop.c for copyright information
6  */
7 #include "flexcop.h"
8 
9 #define FC_MAX_I2C_RETRIES 100000
10 
11 static int flexcop_i2c_operation(struct flexcop_device *fc,
12 		flexcop_ibi_value *r100)
13 {
14 	int i;
15 	flexcop_ibi_value r;
16 
17 	r100->tw_sm_c_100.working_start = 1;
18 	deb_i2c("r100 before: %08x\n",r100->raw);
19 
20 	fc->write_ibi_reg(fc, tw_sm_c_100, ibi_zero);
21 	fc->write_ibi_reg(fc, tw_sm_c_100, *r100); /* initiating i2c operation */
22 
23 	for (i = 0; i < FC_MAX_I2C_RETRIES; i++) {
24 		r = fc->read_ibi_reg(fc, tw_sm_c_100);
25 
26 		if (!r.tw_sm_c_100.no_base_addr_ack_error) {
27 			if (r.tw_sm_c_100.st_done) {
28 				*r100 = r;
29 				deb_i2c("i2c success\n");
30 				return 0;
31 			}
32 		} else {
33 			deb_i2c("suffering from an i2c ack_error\n");
34 			return -EREMOTEIO;
35 		}
36 	}
37 	deb_i2c("tried %d times i2c operation, never finished or too many ack errors.\n",
38 		i);
39 	return -EREMOTEIO;
40 }
41 
42 static int flexcop_i2c_read4(struct flexcop_i2c_adapter *i2c,
43 		flexcop_ibi_value r100, u8 *buf)
44 {
45 	flexcop_ibi_value r104;
46 	int len = r100.tw_sm_c_100.total_bytes,
47 		/* remember total_bytes is buflen-1 */
48 		ret;
49 
50 	/* work-around to have CableStar2 and SkyStar2 rev 2.7 work
51 	 * correctly:
52 	 *
53 	 * the ITD1000 is behind an i2c-gate which closes automatically
54 	 * after an i2c-transaction the STV0297 needs 2 consecutive reads
55 	 * one with no_base_addr = 0 and one with 1
56 	 *
57 	 * those two work-arounds are conflictin: we check for the card
58 	 * type, it is set when probing the ITD1000 */
59 	if (i2c->fc->dev_type == FC_SKY_REV27)
60 		r100.tw_sm_c_100.no_base_addr_ack_error = i2c->no_base_addr;
61 
62 	ret = flexcop_i2c_operation(i2c->fc, &r100);
63 	if (ret != 0) {
64 		deb_i2c("Retrying operation\n");
65 		r100.tw_sm_c_100.no_base_addr_ack_error = i2c->no_base_addr;
66 		ret = flexcop_i2c_operation(i2c->fc, &r100);
67 	}
68 	if (ret != 0) {
69 		deb_i2c("read failed. %d\n", ret);
70 		return ret;
71 	}
72 
73 	buf[0] = r100.tw_sm_c_100.data1_reg;
74 
75 	if (len > 0) {
76 		r104 = i2c->fc->read_ibi_reg(i2c->fc, tw_sm_c_104);
77 		deb_i2c("read: r100: %08x, r104: %08x\n", r100.raw, r104.raw);
78 
79 		/* there is at least one more byte, otherwise we wouldn't be here */
80 		buf[1] = r104.tw_sm_c_104.data2_reg;
81 		if (len > 1) buf[2] = r104.tw_sm_c_104.data3_reg;
82 		if (len > 2) buf[3] = r104.tw_sm_c_104.data4_reg;
83 	}
84 	return 0;
85 }
86 
87 static int flexcop_i2c_write4(struct flexcop_device *fc,
88 		flexcop_ibi_value r100, u8 *buf)
89 {
90 	flexcop_ibi_value r104;
91 	int len = r100.tw_sm_c_100.total_bytes; /* remember total_bytes is buflen-1 */
92 	r104.raw = 0;
93 
94 	/* there is at least one byte, otherwise we wouldn't be here */
95 	r100.tw_sm_c_100.data1_reg = buf[0];
96 	r104.tw_sm_c_104.data2_reg = len > 0 ? buf[1] : 0;
97 	r104.tw_sm_c_104.data3_reg = len > 1 ? buf[2] : 0;
98 	r104.tw_sm_c_104.data4_reg = len > 2 ? buf[3] : 0;
99 
100 	deb_i2c("write: r100: %08x, r104: %08x\n", r100.raw, r104.raw);
101 
102 	/* write the additional i2c data before doing the actual i2c operation */
103 	fc->write_ibi_reg(fc, tw_sm_c_104, r104);
104 	return flexcop_i2c_operation(fc, &r100);
105 }
106 
107 int flexcop_i2c_request(struct flexcop_i2c_adapter *i2c,
108 			flexcop_access_op_t op, u8 chipaddr,
109 			u8 start_addr, u8 *buf, u16 size)
110 {
111 	int ret;
112 	int len = size;
113 	u8 *p;
114 	u8 addr = start_addr;
115 
116 	u16 bytes_to_transfer;
117 	flexcop_ibi_value r100;
118 
119 	deb_i2c("port %d %s(%02x): register %02x, size: %d\n",
120 		i2c->port,
121 		op == FC_READ ? "rd" : "wr",
122 		chipaddr, start_addr, size);
123 	r100.raw = 0;
124 	r100.tw_sm_c_100.chipaddr = chipaddr;
125 	r100.tw_sm_c_100.twoWS_rw = op;
126 	r100.tw_sm_c_100.twoWS_port_reg = i2c->port;
127 
128 	/* in that case addr is the only value ->
129 	 * we write it twice as baseaddr and val0
130 	 * BBTI is doing it like that for ISL6421 at least */
131 	if (i2c->no_base_addr && len == 0 && op == FC_WRITE) {
132 		buf = &start_addr;
133 		len = 1;
134 	}
135 
136 	p = buf;
137 
138 	while (len != 0) {
139 		bytes_to_transfer = len > 4 ? 4 : len;
140 
141 		r100.tw_sm_c_100.total_bytes = bytes_to_transfer - 1;
142 		r100.tw_sm_c_100.baseaddr = addr;
143 
144 		if (op == FC_READ)
145 			ret = flexcop_i2c_read4(i2c, r100, p);
146 		else
147 			ret = flexcop_i2c_write4(i2c->fc, r100, p);
148 
149 		if (ret < 0)
150 			return ret;
151 
152 		p  += bytes_to_transfer;
153 		addr += bytes_to_transfer;
154 		len  -= bytes_to_transfer;
155 	}
156 	deb_i2c_dump("port %d %s(%02x): register %02x: %*ph\n",
157 		i2c->port,
158 		op == FC_READ ? "rd" : "wr",
159 		chipaddr, start_addr, size, buf);
160 
161 	return 0;
162 }
163 /* exported for PCI i2c */
164 EXPORT_SYMBOL(flexcop_i2c_request);
165 
166 /* master xfer callback for demodulator */
167 static int flexcop_master_xfer(struct i2c_adapter *i2c_adap,
168 		struct i2c_msg msgs[], int num)
169 {
170 	struct flexcop_i2c_adapter *i2c = i2c_get_adapdata(i2c_adap);
171 	int i, ret = 0;
172 
173 	/* Some drivers use 1 byte or 0 byte reads as probes, which this
174 	 * driver doesn't support.  These probes will always fail, so this
175 	 * hack makes them always succeed.  If one knew how, it would of
176 	 * course be better to actually do the read.  */
177 	if (num == 1 && msgs[0].flags == I2C_M_RD && msgs[0].len <= 1)
178 		return 1;
179 
180 	if (mutex_lock_interruptible(&i2c->fc->i2c_mutex))
181 		return -ERESTARTSYS;
182 
183 	for (i = 0; i < num; i++) {
184 		/* reading */
185 		if (i+1 < num && (msgs[i+1].flags == I2C_M_RD)) {
186 			ret = i2c->fc->i2c_request(i2c, FC_READ, msgs[i].addr,
187 					msgs[i].buf[0], msgs[i+1].buf,
188 					msgs[i+1].len);
189 			i++; /* skip the following message */
190 		} else /* writing */
191 			ret = i2c->fc->i2c_request(i2c, FC_WRITE, msgs[i].addr,
192 					msgs[i].buf[0], &msgs[i].buf[1],
193 					msgs[i].len - 1);
194 		if (ret < 0) {
195 			deb_i2c("i2c master_xfer failed");
196 			break;
197 		}
198 	}
199 
200 	mutex_unlock(&i2c->fc->i2c_mutex);
201 
202 	if (ret == 0)
203 		ret = num;
204 	return ret;
205 }
206 
207 static u32 flexcop_i2c_func(struct i2c_adapter *adapter)
208 {
209 	return I2C_FUNC_I2C;
210 }
211 
212 static struct i2c_algorithm flexcop_algo = {
213 	.master_xfer	= flexcop_master_xfer,
214 	.functionality	= flexcop_i2c_func,
215 };
216 
217 int flexcop_i2c_init(struct flexcop_device *fc)
218 {
219 	int ret;
220 	mutex_init(&fc->i2c_mutex);
221 
222 	fc->fc_i2c_adap[0].fc = fc;
223 	fc->fc_i2c_adap[1].fc = fc;
224 	fc->fc_i2c_adap[2].fc = fc;
225 	fc->fc_i2c_adap[0].port = FC_I2C_PORT_DEMOD;
226 	fc->fc_i2c_adap[1].port = FC_I2C_PORT_EEPROM;
227 	fc->fc_i2c_adap[2].port = FC_I2C_PORT_TUNER;
228 
229 	strscpy(fc->fc_i2c_adap[0].i2c_adap.name, "B2C2 FlexCop I2C to demod",
230 		sizeof(fc->fc_i2c_adap[0].i2c_adap.name));
231 	strscpy(fc->fc_i2c_adap[1].i2c_adap.name, "B2C2 FlexCop I2C to eeprom",
232 		sizeof(fc->fc_i2c_adap[1].i2c_adap.name));
233 	strscpy(fc->fc_i2c_adap[2].i2c_adap.name, "B2C2 FlexCop I2C to tuner",
234 		sizeof(fc->fc_i2c_adap[2].i2c_adap.name));
235 
236 	i2c_set_adapdata(&fc->fc_i2c_adap[0].i2c_adap, &fc->fc_i2c_adap[0]);
237 	i2c_set_adapdata(&fc->fc_i2c_adap[1].i2c_adap, &fc->fc_i2c_adap[1]);
238 	i2c_set_adapdata(&fc->fc_i2c_adap[2].i2c_adap, &fc->fc_i2c_adap[2]);
239 
240 	fc->fc_i2c_adap[0].i2c_adap.algo =
241 		fc->fc_i2c_adap[1].i2c_adap.algo =
242 		fc->fc_i2c_adap[2].i2c_adap.algo = &flexcop_algo;
243 	fc->fc_i2c_adap[0].i2c_adap.algo_data =
244 		fc->fc_i2c_adap[1].i2c_adap.algo_data =
245 		fc->fc_i2c_adap[2].i2c_adap.algo_data = NULL;
246 	fc->fc_i2c_adap[0].i2c_adap.dev.parent =
247 		fc->fc_i2c_adap[1].i2c_adap.dev.parent =
248 		fc->fc_i2c_adap[2].i2c_adap.dev.parent = fc->dev;
249 
250 	ret = i2c_add_adapter(&fc->fc_i2c_adap[0].i2c_adap);
251 	if (ret < 0)
252 		return ret;
253 
254 	ret = i2c_add_adapter(&fc->fc_i2c_adap[1].i2c_adap);
255 	if (ret < 0)
256 		goto adap_1_failed;
257 
258 	ret = i2c_add_adapter(&fc->fc_i2c_adap[2].i2c_adap);
259 	if (ret < 0)
260 		goto adap_2_failed;
261 
262 	fc->init_state |= FC_STATE_I2C_INIT;
263 	return 0;
264 
265 adap_2_failed:
266 	i2c_del_adapter(&fc->fc_i2c_adap[1].i2c_adap);
267 adap_1_failed:
268 	i2c_del_adapter(&fc->fc_i2c_adap[0].i2c_adap);
269 	return ret;
270 }
271 
272 void flexcop_i2c_exit(struct flexcop_device *fc)
273 {
274 	if (fc->init_state & FC_STATE_I2C_INIT) {
275 		i2c_del_adapter(&fc->fc_i2c_adap[2].i2c_adap);
276 		i2c_del_adapter(&fc->fc_i2c_adap[1].i2c_adap);
277 		i2c_del_adapter(&fc->fc_i2c_adap[0].i2c_adap);
278 	}
279 	fc->init_state &= ~FC_STATE_I2C_INIT;
280 }
281