flexcop-i2c.c

  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
 11static 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
 42static 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
 87static 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
107int 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 */
164EXPORT_SYMBOL(flexcop_i2c_request);
165
166/* master xfer callback for demodulator */
167static 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
207static u32 flexcop_i2c_func(struct i2c_adapter *adapter)
208{
209	return I2C_FUNC_I2C;
210}
211
212static const struct i2c_algorithm flexcop_algo = {
213	.master_xfer	= flexcop_master_xfer,
214	.functionality	= flexcop_i2c_func,
215};
216
217int 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
265adap_2_failed:
266	i2c_del_adapter(&fc->fc_i2c_adap[1].i2c_adap);
267adap_1_failed:
268	i2c_del_adapter(&fc->fc_i2c_adap[0].i2c_adap);
269	return ret;
270}
271
272void 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}