drivers/media/pci/pt3/pt3_i2c.c

   1 /*
   2  * Earthsoft PT3 driver
   3  *
   4  * Copyright (C) 2014 Akihiro Tsukada <tskd08@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation version 2.
   9  *
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16 #include <linux/delay.h>
  17 #include <linux/device.h>
  18 #include <linux/i2c.h>
  19 #include <linux/io.h>
  20 #include <linux/pci.h>
  21
  22 #include "pt3.h"
  23
  24 #define PT3_I2C_BASE  2048
  25 #define PT3_CMD_ADDR_NORMAL 0
  26 #define PT3_CMD_ADDR_INIT_DEMOD  4096
  27 #define PT3_CMD_ADDR_INIT_TUNER  (4096 + 2042)
  28
  29 /* masks for I2C status register */
  30 #define STAT_SEQ_RUNNING 0x1
  31 #define STAT_SEQ_ERROR   0x6
  32 #define STAT_NO_SEQ      0x8
  33
  34 #define PT3_I2C_RUN   (1 << 16)
  35 #define PT3_I2C_RESET (1 << 17)
  36
  37 enum ctl_cmd {
  38         I_END,
  39         I_ADDRESS,
  40         I_CLOCK_L,
  41         I_CLOCK_H,
  42         I_DATA_L,
  43         I_DATA_H,
  44         I_RESET,
  45         I_SLEEP,
  46         I_DATA_L_NOP  = 0x08,
  47         I_DATA_H_NOP  = 0x0c,
  48         I_DATA_H_READ = 0x0d,
  49         I_DATA_H_ACK0 = 0x0e,
  50         I_DATA_H_ACK1 = 0x0f,
  51 };
  52
  53
  54 static void cmdbuf_add(struct pt3_i2cbuf *cbuf, enum ctl_cmd cmd)
  55 {
  56         int buf_idx;
  57
  58         if ((cbuf->num_cmds % 2) == 0)
  59                 cbuf->tmp = cmd;
  60         else {
  61                 cbuf->tmp |= cmd << 4;
  62                 buf_idx = cbuf->num_cmds / 2;
  63                 if (buf_idx < ARRAY_SIZE(cbuf->data))
  64                         cbuf->data[buf_idx] = cbuf->tmp;
  65         }
  66         cbuf->num_cmds++;
  67 }
  68
  69 static void put_end(struct pt3_i2cbuf *cbuf)
  70 {
  71         cmdbuf_add(cbuf, I_END);
  72         if (cbuf->num_cmds % 2)
  73                 cmdbuf_add(cbuf, I_END);
  74 }
  75
  76 static void put_start(struct pt3_i2cbuf *cbuf)
  77 {
  78         cmdbuf_add(cbuf, I_DATA_H);
  79         cmdbuf_add(cbuf, I_CLOCK_H);
  80         cmdbuf_add(cbuf, I_DATA_L);
  81         cmdbuf_add(cbuf, I_CLOCK_L);
  82 }
  83
  84 static void put_byte_write(struct pt3_i2cbuf *cbuf, u8 val)
  85 {
  86         u8 mask;
  87
  88         for (mask = 0x80; mask > 0; mask >>= 1)
  89                 cmdbuf_add(cbuf, (val & mask) ? I_DATA_H_NOP : I_DATA_L_NOP);
  90         cmdbuf_add(cbuf, I_DATA_H_ACK0);
  91 }
  92
  93 static void put_byte_read(struct pt3_i2cbuf *cbuf, u32 size)
  94 {
  95         int i, j;
  96
  97         for (i = 0; i < size; i++) {
  98                 for (j = 0; j < 8; j++)
  99                         cmdbuf_add(cbuf, I_DATA_H_READ);
 100                 cmdbuf_add(cbuf, (i == size - 1) ? I_DATA_H_NOP : I_DATA_L_NOP);
 101         }
 102 }
 103
 104 static void put_stop(struct pt3_i2cbuf *cbuf)
 105 {
 106         cmdbuf_add(cbuf, I_DATA_L);
 107         cmdbuf_add(cbuf, I_CLOCK_H);
 108         cmdbuf_add(cbuf, I_DATA_H);
 109 }
 110
 111
 112 /* translates msgs to internal commands for bit-banging */
 113 static void translate(struct pt3_i2cbuf *cbuf, struct i2c_msg *msgs, int num)
 114 {
 115         int i, j;
 116         bool rd;
 117
 118         cbuf->num_cmds = 0;
 119         for (i = 0; i < num; i++) {
 120                 rd = !!(msgs[i].flags & I2C_M_RD);
 121                 put_start(cbuf);
 122                 put_byte_write(cbuf, msgs[i].addr << 1 | rd);
 123                 if (rd)
 124                         put_byte_read(cbuf, msgs[i].len);
 125                 else
 126                         for (j = 0; j < msgs[i].len; j++)
 127                                 put_byte_write(cbuf, msgs[i].buf[j]);
 128         }
 129         if (num > 0) {
 130                 put_stop(cbuf);
 131                 put_end(cbuf);
 132         }
 133 }
 134
 135 static int wait_i2c_result(struct pt3_board *pt3, u32 *result, int max_wait)
 136 {
 137         int i;
 138         u32 v;
 139
 140         for (i = 0; i < max_wait; i++) {
 141                 v = ioread32(pt3->regs[0] + REG_I2C_R);
 142                 if (!(v & STAT_SEQ_RUNNING))
 143                         break;
 144                 usleep_range(500, 750);
 145         }
 146         if (i >= max_wait)
 147                 return -EIO;
 148         if (result)
 149                 *result = v;
 150         return 0;
 151 }
 152
 153 /* send [pre-]translated i2c msgs stored at addr */
 154 static int send_i2c_cmd(struct pt3_board *pt3, u32 addr)
 155 {
 156         u32 ret;
 157
 158         /* make sure that previous transactions had finished */
 159         if (wait_i2c_result(pt3, NULL, 50)) {
 160                 dev_warn(&pt3->pdev->dev, "(%s) prev. transaction stalled\n",
 161                                 __func__);
 162                 return -EIO;
 163         }
 164
 165         iowrite32(PT3_I2C_RUN | addr, pt3->regs[0] + REG_I2C_W);
 166         usleep_range(200, 300);
 167         /* wait for the current transaction to finish */
 168         if (wait_i2c_result(pt3, &ret, 500) || (ret & STAT_SEQ_ERROR)) {
 169                 dev_warn(&pt3->pdev->dev, "(%s) failed.\n", __func__);
 170                 return -EIO;
 171         }
 172         return 0;
 173 }
 174
 175
 176 /* init commands for each demod are combined into one transaction
 177  *  and hidden in ROM with the address PT3_CMD_ADDR_INIT_DEMOD.
 178  */
 179 int  pt3_init_all_demods(struct pt3_board *pt3)
 180 {
 181         ioread32(pt3->regs[0] + REG_I2C_R);
 182         return send_i2c_cmd(pt3, PT3_CMD_ADDR_INIT_DEMOD);
 183 }
 184
 185 /* init commands for two ISDB-T tuners are hidden in ROM. */
 186 int  pt3_init_all_mxl301rf(struct pt3_board *pt3)
 187 {
 188         usleep_range(1000, 2000);
 189         return send_i2c_cmd(pt3, PT3_CMD_ADDR_INIT_TUNER);
 190 }
 191
 192 void pt3_i2c_reset(struct pt3_board *pt3)
 193 {
 194         iowrite32(PT3_I2C_RESET, pt3->regs[0] + REG_I2C_W);
 195 }
 196
 197 /*
 198  * I2C algorithm
 199  */
 200 int
 201 pt3_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 202 {
 203         struct pt3_board *pt3;
 204         struct pt3_i2cbuf *cbuf;
 205         int i;
 206         void __iomem *p;
 207
 208         pt3 = i2c_get_adapdata(adap);
 209         cbuf = pt3->i2c_buf;
 210
 211         for (i = 0; i < num; i++)
 212                 if (msgs[i].flags & I2C_M_RECV_LEN) {
 213                         dev_warn(&pt3->pdev->dev,
 214                                 "(%s) I2C_M_RECV_LEN not supported.\n",
 215                                 __func__);
 216                         return -EINVAL;
 217                 }
 218
 219         translate(cbuf, msgs, num);
 220         memcpy_toio(pt3->regs[1] + PT3_I2C_BASE + PT3_CMD_ADDR_NORMAL / 2,
 221                         cbuf->data, cbuf->num_cmds);
 222
 223         if (send_i2c_cmd(pt3, PT3_CMD_ADDR_NORMAL) < 0)
 224                 return -EIO;
 225
 226         p = pt3->regs[1] + PT3_I2C_BASE;
 227         for (i = 0; i < num; i++)
 228                 if ((msgs[i].flags & I2C_M_RD) && msgs[i].len > 0) {
 229                         memcpy_fromio(msgs[i].buf, p, msgs[i].len);
 230                         p += msgs[i].len;
 231                 }
 232
 233         return num;
 234 }
 235
 236 u32 pt3_i2c_functionality(struct i2c_adapter *adap)
 237 {
 238         return I2C_FUNC_I2C;
 239 }