diff options
Diffstat (limited to 'drivers/media/common/saa7146_i2c.c')
| -rw-r--r-- | drivers/media/common/saa7146_i2c.c | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/drivers/media/common/saa7146_i2c.c b/drivers/media/common/saa7146_i2c.c new file mode 100644 index 00000000000..781f23f0cbc --- /dev/null +++ b/drivers/media/common/saa7146_i2c.c @@ -0,0 +1,421 @@ +#include <linux/version.h> +#include <media/saa7146_vv.h> + +static u32 saa7146_i2c_func(struct i2c_adapter *adapter) +{ +//fm DEB_I2C(("'%s'.\n", adapter->name)); + + return I2C_FUNC_I2C + | I2C_FUNC_SMBUS_QUICK + | I2C_FUNC_SMBUS_READ_BYTE | I2C_FUNC_SMBUS_WRITE_BYTE + | I2C_FUNC_SMBUS_READ_BYTE_DATA | I2C_FUNC_SMBUS_WRITE_BYTE_DATA; +} + +/* this function returns the status-register of our i2c-device */ +static inline u32 saa7146_i2c_status(struct saa7146_dev *dev) +{ + u32 iicsta = saa7146_read(dev, I2C_STATUS); +/* + DEB_I2C(("status: 0x%08x\n",iicsta)); +*/ + return iicsta; +} + +/* this function runs through the i2c-messages and prepares the data to be + sent through the saa7146. have a look at the specifications p. 122 ff + to understand this. it returns the number of u32s to send, or -1 + in case of an error. */ +static int saa7146_i2c_msg_prepare(const struct i2c_msg *m, int num, u32 *op) +{ + int h1, h2; + int i, j, addr; + int mem = 0, op_count = 0; + + /* first determine size of needed memory */ + for(i = 0; i < num; i++) { + mem += m[i].len + 1; + } + + /* worst case: we need one u32 for three bytes to be send + plus one extra byte to address the device */ + mem = 1 + ((mem-1) / 3); + + /* we assume that op points to a memory of at least SAA7146_I2C_MEM bytes + size. if we exceed this limit... */ + if ( (4*mem) > SAA7146_I2C_MEM ) { +//fm DEB_I2C(("cannot prepare i2c-message.\n")); + return -ENOMEM; + } + + /* be careful: clear out the i2c-mem first */ + memset(op,0,sizeof(u32)*mem); + + /* loop through all messages */ + for(i = 0; i < num; i++) { + + /* insert the address of the i2c-slave. + note: we get 7 bit i2c-addresses, + so we have to perform a translation */ + addr = (m[i].addr*2) + ( (0 != (m[i].flags & I2C_M_RD)) ? 1 : 0); + h1 = op_count/3; h2 = op_count%3; + op[h1] |= ( (u8)addr << ((3-h2)*8)); + op[h1] |= (SAA7146_I2C_START << ((3-h2)*2)); + op_count++; + + /* loop through all bytes of message i */ + for(j = 0; j < m[i].len; j++) { + /* insert the data bytes */ + h1 = op_count/3; h2 = op_count%3; + op[h1] |= ( (u32)((u8)m[i].buf[j]) << ((3-h2)*8)); + op[h1] |= ( SAA7146_I2C_CONT << ((3-h2)*2)); + op_count++; + } + + } + + /* have a look at the last byte inserted: + if it was: ...CONT change it to ...STOP */ + h1 = (op_count-1)/3; h2 = (op_count-1)%3; + if ( SAA7146_I2C_CONT == (0x3 & (op[h1] >> ((3-h2)*2))) ) { + op[h1] &= ~(0x2 << ((3-h2)*2)); + op[h1] |= (SAA7146_I2C_STOP << ((3-h2)*2)); + } + + /* return the number of u32s to send */ + return mem; +} + +/* this functions loops through all i2c-messages. normally, it should determine + which bytes were read through the adapter and write them back to the corresponding + i2c-message. but instead, we simply write back all bytes. + fixme: this could be improved. */ +static int saa7146_i2c_msg_cleanup(const struct i2c_msg *m, int num, u32 *op) +{ + int i, j; + int op_count = 0; + + /* loop through all messages */ + for(i = 0; i < num; i++) { + + op_count++; + + /* loop throgh all bytes of message i */ + for(j = 0; j < m[i].len; j++) { + /* write back all bytes that could have been read */ + m[i].buf[j] = (op[op_count/3] >> ((3-(op_count%3))*8)); + op_count++; + } + } + + return 0; +} + +/* this functions resets the i2c-device and returns 0 if everything was fine, otherwise -1 */ +static int saa7146_i2c_reset(struct saa7146_dev *dev) +{ + /* get current status */ + u32 status = saa7146_i2c_status(dev); + + /* clear registers for sure */ + saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate); + saa7146_write(dev, I2C_TRANSFER, 0); + + /* check if any operation is still in progress */ + if ( 0 != ( status & SAA7146_I2C_BUSY) ) { + + /* yes, kill ongoing operation */ + DEB_I2C(("busy_state detected.\n")); + + /* set "ABORT-OPERATION"-bit (bit 7)*/ + saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07)); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + msleep(SAA7146_I2C_DELAY); + + /* clear all error-bits pending; this is needed because p.123, note 1 */ + saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + msleep(SAA7146_I2C_DELAY); + } + + /* check if any error is (still) present. (this can be necessary because p.123, note 1) */ + status = saa7146_i2c_status(dev); + + if ( dev->i2c_bitrate != status ) { + + DEB_I2C(("error_state detected. status:0x%08x\n",status)); + + /* Repeat the abort operation. This seems to be necessary + after serious protocol errors caused by e.g. the SAA7740 */ + saa7146_write(dev, I2C_STATUS, (dev->i2c_bitrate | MASK_07)); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + msleep(SAA7146_I2C_DELAY); + + /* clear all error-bits pending */ + saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + msleep(SAA7146_I2C_DELAY); + + /* the data sheet says it might be necessary to clear the status + twice after an abort */ + saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + msleep(SAA7146_I2C_DELAY); + } + + /* if any error is still present, a fatal error has occured ... */ + status = saa7146_i2c_status(dev); + if ( dev->i2c_bitrate != status ) { + DEB_I2C(("fatal error. status:0x%08x\n",status)); + return -1; + } + + return 0; +} + +/* this functions writes out the data-byte 'dword' to the i2c-device. + it returns 0 if ok, -1 if the transfer failed, -2 if the transfer + failed badly (e.g. address error) */ +static int saa7146_i2c_writeout(struct saa7146_dev *dev, u32* dword, int short_delay) +{ + u32 status = 0, mc2 = 0; + int trial = 0; + unsigned long timeout; + + /* write out i2c-command */ + DEB_I2C(("before: 0x%08x (status: 0x%08x), %d\n",*dword,saa7146_read(dev, I2C_STATUS), dev->i2c_op)); + + if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) { + + saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate); + saa7146_write(dev, I2C_TRANSFER, *dword); + + dev->i2c_op = 1; + SAA7146_IER_ENABLE(dev, MASK_16|MASK_17); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + + wait_event_interruptible(dev->i2c_wq, dev->i2c_op == 0); + if (signal_pending (current)) { + /* a signal arrived */ + return -ERESTARTSYS; + } + status = saa7146_read(dev, I2C_STATUS); + } else { + saa7146_write(dev, I2C_STATUS, dev->i2c_bitrate); + saa7146_write(dev, I2C_TRANSFER, *dword); + saa7146_write(dev, MC2, (MASK_00 | MASK_16)); + + /* do not poll for i2c-status before upload is complete */ + timeout = jiffies + HZ/100 + 1; /* 10ms */ + while(1) { + mc2 = (saa7146_read(dev, MC2) & 0x1); + if( 0 != mc2 ) { + break; + } + if (time_after(jiffies,timeout)) { + printk(KERN_WARNING "saa7146_i2c_writeout: timed out waiting for MC2\n"); + return -EIO; + } + } + /* wait until we get a transfer done or error */ + timeout = jiffies + HZ/100 + 1; /* 10ms */ + while(1) { + /** + * first read usually delivers bogus results... + */ + saa7146_i2c_status(dev); + status = saa7146_i2c_status(dev); + if ((status & 0x3) != 1) + break; + if (time_after(jiffies,timeout)) { + /* this is normal when probing the bus + * (no answer from nonexisistant device...) + */ + DEB_I2C(("saa7146_i2c_writeout: timed out waiting for end of xfer\n")); + return -EIO; + } + if ((++trial < 20) && short_delay) + udelay(10); + else + msleep(1); + } + } + + /* give a detailed status report */ + if ( 0 != (status & SAA7146_I2C_ERR)) { + + if( 0 != (status & SAA7146_I2C_SPERR) ) { + DEB_I2C(("error due to invalid start/stop condition.\n")); + } + if( 0 != (status & SAA7146_I2C_DTERR) ) { + DEB_I2C(("error in data transmission.\n")); + } + if( 0 != (status & SAA7146_I2C_DRERR) ) { + DEB_I2C(("error when receiving data.\n")); + } + if( 0 != (status & SAA7146_I2C_AL) ) { + DEB_I2C(("error because arbitration lost.\n")); + } + + /* we handle address-errors here */ + if( 0 != (status & SAA7146_I2C_APERR) ) { + DEB_I2C(("error in address phase.\n")); + return -EREMOTEIO; + } + + return -EIO; + } + + /* read back data, just in case we were reading ... */ + *dword = saa7146_read(dev, I2C_TRANSFER); + + DEB_I2C(("after: 0x%08x\n",*dword)); + return 0; +} + +int saa7146_i2c_transfer(struct saa7146_dev *dev, const struct i2c_msg *msgs, int num, int retries) +{ + int i = 0, count = 0; + u32* buffer = dev->d_i2c.cpu_addr; + int err = 0; + int address_err = 0; + int short_delay = 0; + + if (down_interruptible (&dev->i2c_lock)) + return -ERESTARTSYS; + + for(i=0;i<num;i++) { + DEB_I2C(("msg:%d/%d\n",i+1,num)); + } + + /* prepare the message(s), get number of u32s to transfer */ + count = saa7146_i2c_msg_prepare(msgs, num, buffer); + if ( 0 > count ) { + err = -1; + goto out; + } + + if ( count > 3 || 0 != (SAA7146_I2C_SHORT_DELAY & dev->ext->flags) ) + short_delay = 1; + + do { + /* reset the i2c-device if necessary */ + err = saa7146_i2c_reset(dev); + if ( 0 > err ) { + DEB_I2C(("could not reset i2c-device.\n")); + goto out; + } + + /* write out the u32s one after another */ + for(i = 0; i < count; i++) { + err = saa7146_i2c_writeout(dev, &buffer[i], short_delay); + if ( 0 != err) { + /* this one is unsatisfying: some i2c slaves on some + dvb cards don't acknowledge correctly, so the saa7146 + thinks that an address error occured. in that case, the + transaction should be retrying, even if an address error + occured. analog saa7146 based cards extensively rely on + i2c address probing, however, and address errors indicate that a + device is really *not* there. retrying in that case + increases the time the device needs to probe greatly, so + it should be avoided. because of the fact, that only + analog based cards use irq based i2c transactions (for dvb + cards, this screwes up other interrupt sources), we bail out + completely for analog cards after an address error and trust + the saa7146 address error detection. */ + if ( -EREMOTEIO == err ) { + if( 0 != (SAA7146_USE_I2C_IRQ & dev->ext->flags)) { + goto out; + } + address_err++; + } + DEB_I2C(("error while sending message(s). starting again.\n")); + break; + } + } + if( 0 == err ) { + err = num; + break; + } + + /* delay a bit before retrying */ + msleep(10); + + } while (err != num && retries--); + + /* if every retry had an address error, exit right away */ + if (address_err == retries) { + goto out; + } + + /* if any things had to be read, get the results */ + if ( 0 != saa7146_i2c_msg_cleanup(msgs, num, buffer)) { + DEB_I2C(("could not cleanup i2c-message.\n")); + err = -1; + goto out; + } + + /* return the number of delivered messages */ + DEB_I2C(("transmission successful. (msg:%d).\n",err)); +out: + /* another bug in revision 0: the i2c-registers get uploaded randomly by other + uploads, so we better clear them out before continueing */ + if( 0 == dev->revision ) { + u32 zero = 0; + saa7146_i2c_reset(dev); + if( 0 != saa7146_i2c_writeout(dev, &zero, short_delay)) { + INFO(("revision 0 error. this should never happen.\n")); + } + } + + up(&dev->i2c_lock); + return err; +} + +/* utility functions */ +static int saa7146_i2c_xfer(struct i2c_adapter* adapter, struct i2c_msg *msg, int num) +{ + struct saa7146_dev* dev = i2c_get_adapdata(adapter); + + /* use helper function to transfer data */ + return saa7146_i2c_transfer(dev, msg, num, adapter->retries); +} + + +/*****************************************************************************/ +/* i2c-adapter helper functions */ +#include <linux/i2c-id.h> + +/* exported algorithm data */ +static struct i2c_algorithm saa7146_algo = { + .name = "saa7146 i2c algorithm", + .id = I2C_ALGO_SAA7146, + .master_xfer = saa7146_i2c_xfer, + .functionality = saa7146_i2c_func, +}; + +int saa7146_i2c_adapter_prepare(struct saa7146_dev *dev, struct i2c_adapter *i2c_adapter, u32 bitrate) +{ + DEB_EE(("bitrate: 0x%08x\n",bitrate)); + + /* enable i2c-port pins */ + saa7146_write(dev, MC1, (MASK_08 | MASK_24)); + + dev->i2c_bitrate = bitrate; + saa7146_i2c_reset(dev); + + if( NULL != i2c_adapter ) { +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)) + i2c_adapter->data = dev; +#else + BUG_ON(!i2c_adapter->class); + i2c_set_adapdata(i2c_adapter,dev); +#endif + i2c_adapter->algo = &saa7146_algo; + i2c_adapter->algo_data = NULL; + i2c_adapter->id = I2C_ALGO_SAA7146; + i2c_adapter->timeout = SAA7146_I2C_TIMEOUT; + i2c_adapter->retries = SAA7146_I2C_RETRIES; + } + + return 0; +} |