drivers/media/common/b2c2/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
  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 }