pci/cx25821/cx25821-i2c.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  Driver for the Conexant CX25821 PCIe bridge
0004  *
0005  *  Copyright (C) 2009 Conexant Systems Inc.
0006  *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
0007  *  Based on Steven Toth <stoth@linuxtv.org> cx23885 driver
0008  */
0009
0010 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0011
0012 #include <linux/module.h>
0013 #include <linux/i2c.h>
0014 #include "cx25821.h"
0015
0016 static unsigned int i2c_debug;
0017 module_param(i2c_debug, int, 0644);
0018 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
0019
0020 static unsigned int i2c_scan;
0021 module_param(i2c_scan, int, 0444);
0022 MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
0023
0024 #define dprintk(level, fmt, arg...)                 \
0025 do {                                    \
0026     if (i2c_debug >= level)                     \
0027         printk(KERN_DEBUG "%s/0: " fmt, dev->name, ##arg);  \
0028 } while (0)
0029
0030 #define I2C_WAIT_DELAY 32
0031 #define I2C_WAIT_RETRY 64
0032
0033 #define I2C_EXTEND  (1 << 3)
0034 #define I2C_NOSTOP  (1 << 4)
0035
0036 static inline int i2c_slave_did_ack(struct i2c_adapter *i2c_adap)
0037 {
0038     struct cx25821_i2c *bus = i2c_adap->algo_data;
0039     struct cx25821_dev *dev = bus->dev;
0040     return cx_read(bus->reg_stat) & 0x01;
0041 }
0042
0043 static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
0044 {
0045     struct cx25821_i2c *bus = i2c_adap->algo_data;
0046     struct cx25821_dev *dev = bus->dev;
0047     return cx_read(bus->reg_stat) & 0x02 ? 1 : 0;
0048 }
0049
0050 static int i2c_wait_done(struct i2c_adapter *i2c_adap)
0051 {
0052     int count;
0053
0054     for (count = 0; count < I2C_WAIT_RETRY; count++) {
0055         if (!i2c_is_busy(i2c_adap))
0056             break;
0057         udelay(I2C_WAIT_DELAY);
0058     }
0059
0060     if (I2C_WAIT_RETRY == count)
0061         return 0;
0062
0063     return 1;
0064 }
0065
0066 static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
0067              const struct i2c_msg *msg, int joined_rlen)
0068 {
0069     struct cx25821_i2c *bus = i2c_adap->algo_data;
0070     struct cx25821_dev *dev = bus->dev;
0071     u32 wdata, addr, ctrl;
0072     int retval, cnt;
0073
0074     if (joined_rlen)
0075         dprintk(1, "%s(msg->wlen=%d, nextmsg->rlen=%d)\n", __func__,
0076             msg->len, joined_rlen);
0077     else
0078         dprintk(1, "%s(msg->len=%d)\n", __func__, msg->len);
0079
0080     /* Deal with i2c probe functions with zero payload */
0081     if (msg->len == 0) {
0082         cx_write(bus->reg_addr, msg->addr << 25);
0083         cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2));
0084
0085         if (!i2c_wait_done(i2c_adap))
0086             return -EIO;
0087
0088         if (!i2c_slave_did_ack(i2c_adap))
0089             return -EIO;
0090
0091         dprintk(1, "%s(): returns 0\n", __func__);
0092         return 0;
0093     }
0094
0095     /* dev, reg + first byte */
0096     addr = (msg->addr << 25) | msg->buf[0];
0097     wdata = msg->buf[0];
0098
0099     ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
0100
0101     if (msg->len > 1)
0102         ctrl |= I2C_NOSTOP | I2C_EXTEND;
0103     else if (joined_rlen)
0104         ctrl |= I2C_NOSTOP;
0105
0106     cx_write(bus->reg_addr, addr);
0107     cx_write(bus->reg_wdata, wdata);
0108     cx_write(bus->reg_ctrl, ctrl);
0109
0110     retval = i2c_wait_done(i2c_adap);
0111     if (retval < 0)
0112         goto err;
0113
0114     if (retval == 0)
0115         goto eio;
0116
0117     if (i2c_debug) {
0118         if (!(ctrl & I2C_NOSTOP))
0119             printk(" >\n");
0120     }
0121
0122     for (cnt = 1; cnt < msg->len; cnt++) {
0123         /* following bytes */
0124         wdata = msg->buf[cnt];
0125         ctrl = bus->i2c_period | (1 << 12) | (1 << 2);
0126
0127         if (cnt < msg->len - 1)
0128             ctrl |= I2C_NOSTOP | I2C_EXTEND;
0129         else if (joined_rlen)
0130             ctrl |= I2C_NOSTOP;
0131
0132         cx_write(bus->reg_addr, addr);
0133         cx_write(bus->reg_wdata, wdata);
0134         cx_write(bus->reg_ctrl, ctrl);
0135
0136         retval = i2c_wait_done(i2c_adap);
0137         if (retval < 0)
0138             goto err;
0139
0140         if (retval == 0)
0141             goto eio;
0142
0143         if (i2c_debug) {
0144             dprintk(1, " %02x", msg->buf[cnt]);
0145             if (!(ctrl & I2C_NOSTOP))
0146                 dprintk(1, " >\n");
0147         }
0148     }
0149
0150     return msg->len;
0151
0152 eio:
0153     retval = -EIO;
0154 err:
0155     if (i2c_debug)
0156         pr_err(" ERR: %d\n", retval);
0157     return retval;
0158 }
0159
0160 static int i2c_readbytes(struct i2c_adapter *i2c_adap,
0161              const struct i2c_msg *msg, int joined)
0162 {
0163     struct cx25821_i2c *bus = i2c_adap->algo_data;
0164     struct cx25821_dev *dev = bus->dev;
0165     u32 ctrl, cnt;
0166     int retval;
0167
0168     if (i2c_debug && !joined)
0169         dprintk(1, "6-%s(msg->len=%d)\n", __func__, msg->len);
0170
0171     /* Deal with i2c probe functions with zero payload */
0172     if (msg->len == 0) {
0173         cx_write(bus->reg_addr, msg->addr << 25);
0174         cx_write(bus->reg_ctrl, bus->i2c_period | (1 << 2) | 1);
0175         if (!i2c_wait_done(i2c_adap))
0176             return -EIO;
0177         if (!i2c_slave_did_ack(i2c_adap))
0178             return -EIO;
0179
0180         dprintk(1, "%s(): returns 0\n", __func__);
0181         return 0;
0182     }
0183
0184     if (i2c_debug) {
0185         if (joined)
0186             dprintk(1, " R");
0187         else
0188             dprintk(1, " <R %02x", (msg->addr << 1) + 1);
0189     }
0190
0191     for (cnt = 0; cnt < msg->len; cnt++) {
0192
0193         ctrl = bus->i2c_period | (1 << 12) | (1 << 2) | 1;
0194
0195         if (cnt < msg->len - 1)
0196             ctrl |= I2C_NOSTOP | I2C_EXTEND;
0197
0198         cx_write(bus->reg_addr, msg->addr << 25);
0199         cx_write(bus->reg_ctrl, ctrl);
0200
0201         retval = i2c_wait_done(i2c_adap);
0202         if (retval < 0)
0203             goto err;
0204         if (retval == 0)
0205             goto eio;
0206         msg->buf[cnt] = cx_read(bus->reg_rdata) & 0xff;
0207
0208         if (i2c_debug) {
0209             dprintk(1, " %02x", msg->buf[cnt]);
0210             if (!(ctrl & I2C_NOSTOP))
0211                 dprintk(1, " >\n");
0212         }
0213     }
0214
0215     return msg->len;
0216 eio:
0217     retval = -EIO;
0218 err:
0219     if (i2c_debug)
0220         pr_err(" ERR: %d\n", retval);
0221     return retval;
0222 }
0223
0224 static int i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
0225 {
0226     struct cx25821_i2c *bus = i2c_adap->algo_data;
0227     struct cx25821_dev *dev = bus->dev;
0228     int i, retval = 0;
0229
0230     dprintk(1, "%s(num = %d)\n", __func__, num);
0231
0232     for (i = 0; i < num; i++) {
0233         dprintk(1, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
0234             __func__, num, msgs[i].addr, msgs[i].len);
0235
0236         if (msgs[i].flags & I2C_M_RD) {
0237             /* read */
0238             retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
0239         } else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
0240                msgs[i].addr == msgs[i + 1].addr) {
0241             /* write then read from same address */
0242             retval = i2c_sendbytes(i2c_adap, &msgs[i],
0243                     msgs[i + 1].len);
0244
0245             if (retval < 0)
0246                 goto err;
0247             i++;
0248             retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
0249         } else {
0250             /* write */
0251             retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
0252         }
0253
0254         if (retval < 0)
0255             goto err;
0256     }
0257     return num;
0258
0259 err:
0260     return retval;
0261 }
0262
0263
0264 static u32 cx25821_functionality(struct i2c_adapter *adap)
0265 {
0266     return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C | I2C_FUNC_SMBUS_WORD_DATA |
0267         I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA;
0268 }
0269
0270 static const struct i2c_algorithm cx25821_i2c_algo_template = {
0271     .master_xfer = i2c_xfer,
0272     .functionality = cx25821_functionality,
0273 #ifdef NEED_ALGO_CONTROL
0274     .algo_control = dummy_algo_control,
0275 #endif
0276 };
0277
0278 static const struct i2c_adapter cx25821_i2c_adap_template = {
0279     .name = "cx25821",
0280     .owner = THIS_MODULE,
0281     .algo = &cx25821_i2c_algo_template,
0282 };
0283
0284 static const struct i2c_client cx25821_i2c_client_template = {
0285     .name = "cx25821 internal",
0286 };
0287
0288 /* init + register i2c adapter */
0289 int cx25821_i2c_register(struct cx25821_i2c *bus)
0290 {
0291     struct cx25821_dev *dev = bus->dev;
0292
0293     dprintk(1, "%s(bus = %d)\n", __func__, bus->nr);
0294
0295     bus->i2c_adap = cx25821_i2c_adap_template;
0296     bus->i2c_client = cx25821_i2c_client_template;
0297     bus->i2c_adap.dev.parent = &dev->pci->dev;
0298
0299     strscpy(bus->i2c_adap.name, bus->dev->name, sizeof(bus->i2c_adap.name));
0300
0301     bus->i2c_adap.algo_data = bus;
0302     i2c_set_adapdata(&bus->i2c_adap, &dev->v4l2_dev);
0303     i2c_add_adapter(&bus->i2c_adap);
0304
0305     bus->i2c_client.adapter = &bus->i2c_adap;
0306
0307     /* set up the I2c */
0308     bus->i2c_client.addr = (0x88 >> 1);
0309
0310     return bus->i2c_rc;
0311 }
0312
0313 int cx25821_i2c_unregister(struct cx25821_i2c *bus)
0314 {
0315     i2c_del_adapter(&bus->i2c_adap);
0316     return 0;
0317 }
0318
0319 #if 0 /* Currently unused */
0320 static void cx25821_av_clk(struct cx25821_dev *dev, int enable)
0321 {
0322     /* write 0 to bus 2 addr 0x144 via i2x_xfer() */
0323     char buffer[3];
0324     struct i2c_msg msg;
0325     dprintk(1, "%s(enabled = %d)\n", __func__, enable);
0326
0327     /* Register 0x144 */
0328     buffer[0] = 0x01;
0329     buffer[1] = 0x44;
0330     if (enable == 1)
0331         buffer[2] = 0x05;
0332     else
0333         buffer[2] = 0x00;
0334
0335     msg.addr = 0x44;
0336     msg.flags = I2C_M_TEN;
0337     msg.len = 3;
0338     msg.buf = buffer;
0339
0340     i2c_xfer(&dev->i2c_bus[0].i2c_adap, &msg, 1);
0341 }
0342 #endif
0343
0344 int cx25821_i2c_read(struct cx25821_i2c *bus, u16 reg_addr, int *value)
0345 {
0346     struct i2c_client *client = &bus->i2c_client;
0347     int v = 0;
0348     u8 addr[2] = { 0, 0 };
0349     u8 buf[4] = { 0, 0, 0, 0 };
0350
0351     struct i2c_msg msgs[2] = {
0352         {
0353             .addr = client->addr,
0354             .flags = 0,
0355             .len = 2,
0356             .buf = addr,
0357         }, {
0358             .addr = client->addr,
0359             .flags = I2C_M_RD,
0360             .len = 4,
0361             .buf = buf,
0362         }
0363     };
0364
0365     addr[0] = (reg_addr >> 8);
0366     addr[1] = (reg_addr & 0xff);
0367     msgs[0].addr = 0x44;
0368     msgs[1].addr = 0x44;
0369
0370     i2c_xfer(client->adapter, msgs, 2);
0371
0372     v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
0373     *value = v;
0374
0375     return v;
0376 }
0377
0378 int cx25821_i2c_write(struct cx25821_i2c *bus, u16 reg_addr, int value)
0379 {
0380     struct i2c_client *client = &bus->i2c_client;
0381     int retval = 0;
0382     u8 buf[6] = { 0, 0, 0, 0, 0, 0 };
0383
0384     struct i2c_msg msgs[1] = {
0385         {
0386             .addr = client->addr,
0387             .flags = 0,
0388             .len = 6,
0389             .buf = buf,
0390         }
0391     };
0392
0393     buf[0] = reg_addr >> 8;
0394     buf[1] = reg_addr & 0xff;
0395     buf[5] = (value >> 24) & 0xff;
0396     buf[4] = (value >> 16) & 0xff;
0397     buf[3] = (value >> 8) & 0xff;
0398     buf[2] = value & 0xff;
0399     client->flags = 0;
0400     msgs[0].addr = 0x44;
0401
0402     retval = i2c_xfer(client->adapter, msgs, 1);
0403
0404     return retval;
0405 }