drivers/media/dvb/b2c2/flexcop-i2c.c

   1 /*
   2  * This file is part of linux driver the digital TV devices equipped with B2C2 FlexcopII(b)/III
   3  *
   4  * flexcop-i2c.c - flexcop internal 2Wire bus (I2C) and dvb i2c initialization
   5  *
   6  * see flexcop.c for copyright information.
   7  */
   8 #include "flexcop.h"
   9
  10 #define FC_MAX_I2C_RETRIES 100000
  11
  12 static int flexcop_i2c_operation(struct flexcop_device *fc, 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) {  /* && !r.tw_sm_c_100.working_start */
  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",i);
  38         return -EREMOTEIO;
  39 }
  40
  41 static int flexcop_i2c_read4(struct flexcop_device *fc, flexcop_ibi_value r100, u8 *buf)
  42 {
  43         flexcop_ibi_value r104;
  44         int len = r100.tw_sm_c_100.total_bytes, /* remember total_bytes is buflen-1 */
  45                 ret;
  46
  47         if ((ret = flexcop_i2c_operation(fc,&r100)) != 0) {
  48                 /* The Cablestar needs a different kind of i2c-transfer (does not
  49                  * support "Repeat Start"):
  50                  * wait for the ACK failure,
  51                  * and do a subsequent read with the Bit 30 enabled
  52                  */
  53                 r100.tw_sm_c_100.no_base_addr_ack_error = 1;
  54                 if ((ret = flexcop_i2c_operation(fc,&r100)) != 0) {
  55                         deb_i2c("no_base_addr read failed. %d\n",ret);
  56                         return ret;
  57                 }
  58         }
  59
  60         buf[0] = r100.tw_sm_c_100.data1_reg;
  61
  62         if (len > 0) {
  63                 r104 = fc->read_ibi_reg(fc,tw_sm_c_104);
  64                 deb_i2c("read: r100: %08x, r104: %08x\n",r100.raw,r104.raw);
  65
  66                 /* there is at least one more byte, otherwise we wouldn't be here */
  67                 buf[1] = r104.tw_sm_c_104.data2_reg;
  68                 if (len > 1) buf[2] = r104.tw_sm_c_104.data3_reg;
  69                 if (len > 2) buf[3] = r104.tw_sm_c_104.data4_reg;
  70         }
  71
  72         return 0;
  73 }
  74
  75 static int flexcop_i2c_write4(struct flexcop_device *fc, flexcop_ibi_value r100, u8 *buf)
  76 {
  77         flexcop_ibi_value r104;
  78         int len = r100.tw_sm_c_100.total_bytes; /* remember total_bytes is buflen-1 */
  79         r104.raw = 0;
  80
  81         /* there is at least one byte, otherwise we wouldn't be here */
  82         r100.tw_sm_c_100.data1_reg = buf[0];
  83
  84         r104.tw_sm_c_104.data2_reg = len > 0 ? buf[1] : 0;
  85         r104.tw_sm_c_104.data3_reg = len > 1 ? buf[2] : 0;
  86         r104.tw_sm_c_104.data4_reg = len > 2 ? buf[3] : 0;
  87
  88         deb_i2c("write: r100: %08x, r104: %08x\n",r100.raw,r104.raw);
  89
  90         /* write the additional i2c data before doing the actual i2c operation */
  91         fc->write_ibi_reg(fc,tw_sm_c_104,r104);
  92         return flexcop_i2c_operation(fc,&r100);
  93 }
  94
  95 int flexcop_i2c_request(struct flexcop_device *fc, flexcop_access_op_t op,
  96                 flexcop_i2c_port_t port, u8 chipaddr, u8 addr, u8 *buf, u16 len)
  97 {
  98         int ret;
  99         u16 bytes_to_transfer;
 100         flexcop_ibi_value r100;
 101
 102         deb_i2c("op = %d\n",op);
 103         r100.raw = 0;
 104         r100.tw_sm_c_100.chipaddr = chipaddr;
 105         r100.tw_sm_c_100.twoWS_rw = op;
 106         r100.tw_sm_c_100.twoWS_port_reg = port;
 107
 108         while (len != 0) {
 109                 bytes_to_transfer = len > 4 ? 4 : len;
 110
 111                 r100.tw_sm_c_100.total_bytes = bytes_to_transfer - 1;
 112                 r100.tw_sm_c_100.baseaddr = addr;
 113
 114                 if (op == FC_READ)
 115                         ret = flexcop_i2c_read4(fc, r100, buf);
 116                 else
 117                         ret = flexcop_i2c_write4(fc,r100, buf);
 118
 119                 if (ret < 0)
 120                         return ret;
 121
 122                 buf  += bytes_to_transfer;
 123                 addr += bytes_to_transfer;
 124                 len  -= bytes_to_transfer;
 125         };
 126
 127         return 0;
 128 }
 129 /* exported for PCI i2c */
 130 EXPORT_SYMBOL(flexcop_i2c_request);
 131
 132 /* master xfer callback for demodulator */
 133 static int flexcop_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
 134 {
 135         struct flexcop_device *fc = i2c_get_adapdata(i2c_adap);
 136         int i, ret = 0;
 137
 138         /* Some drivers use 1 byte or 0 byte reads as probes, which this
 139          * driver doesn't support.  These probes will always fail, so this
 140          * hack makes them always succeed.  If one knew how, it would of
 141          * course be better to actually do the read.  */
 142         if (num == 1 && msgs[0].flags == I2C_M_RD && msgs[0].len <= 1)
 143                 return 1;
 144
 145         if (mutex_lock_interruptible(&fc->i2c_mutex))
 146                 return -ERESTARTSYS;
 147
 148         /* reading */
 149         if (num == 2 &&
 150                 msgs[0].flags == 0 &&
 151                 msgs[1].flags == I2C_M_RD &&
 152                 msgs[0].buf != NULL &&
 153                 msgs[1].buf != NULL) {
 154
 155                 ret = fc->i2c_request(fc, FC_READ, FC_I2C_PORT_DEMOD, msgs[0].addr, msgs[0].buf[0], msgs[1].buf, msgs[1].len);
 156
 157         } else for (i = 0; i < num; i++) { /* writing command */
 158                 if (msgs[i].flags != 0 || msgs[i].buf == NULL || msgs[i].len < 2) {
 159                         ret = -EINVAL;
 160                         break;
 161                 }
 162
 163                 ret = fc->i2c_request(fc, FC_WRITE, FC_I2C_PORT_DEMOD, msgs[i].addr, msgs[i].buf[0], &msgs[i].buf[1], msgs[i].len - 1);
 164         }
 165
 166         if (ret < 0)
 167                 err("i2c master_xfer failed");
 168         else
 169                 ret = num;
 170
 171         mutex_unlock(&fc->i2c_mutex);
 172
 173         return ret;
 174 }
 175
 176 static u32 flexcop_i2c_func(struct i2c_adapter *adapter)
 177 {
 178         return I2C_FUNC_I2C;
 179 }
 180
 181 static struct i2c_algorithm flexcop_algo = {
 182         .master_xfer    = flexcop_master_xfer,
 183         .functionality  = flexcop_i2c_func,
 184 };
 185
 186 int flexcop_i2c_init(struct flexcop_device *fc)
 187 {
 188         int ret;
 189
 190         mutex_init(&fc->i2c_mutex);
 191
 192         memset(&fc->i2c_adap, 0, sizeof(struct i2c_adapter));
 193         strncpy(fc->i2c_adap.name, "B2C2 FlexCop device",
 194                 sizeof(fc->i2c_adap.name));
 195
 196         i2c_set_adapdata(&fc->i2c_adap,fc);
 197
 198         fc->i2c_adap.class          = I2C_CLASS_TV_DIGITAL;
 199         fc->i2c_adap.algo       = &flexcop_algo;
 200         fc->i2c_adap.algo_data  = NULL;
 201         fc->i2c_adap.dev.parent = fc->dev;
 202
 203         if ((ret = i2c_add_adapter(&fc->i2c_adap)) < 0)
 204                 return ret;
 205
 206         fc->init_state |= FC_STATE_I2C_INIT;
 207         return 0;
 208 }
 209
 210 void flexcop_i2c_exit(struct flexcop_device *fc)
 211 {
 212         if (fc->init_state & FC_STATE_I2C_INIT)
 213                 i2c_del_adapter(&fc->i2c_adap);
 214
 215         fc->init_state &= ~FC_STATE_I2C_INIT;
 216 }