linux/drivers/media/common/b2c2/flexcop-i2c.c
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   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 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}
 281
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