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