3  * Device driver for the via ADB on (many) Mac II-class machines
21  *   Rockwell R6522 VIA datasheet
39 static volatile unsigned char *via;  variable
41 /* VIA registers - spaced 0x200 bytes apart */
122 static int status;          /* VIA's ADB status bits captured upon interrupt */
136 	via = via1;  in macii_probe()
171 	via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;  in macii_init_via()
174 	via[B] |= ST_IDLE;  in macii_init_via()
177 	via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;  in macii_init_via()
180 	x = via[SR];  in macii_init_via()
341 	via[ACR] |= SR_OUT;  in macii_start()
343 	via[SR] = req->data[1];  in macii_start()
345 	via[B] = (via[B] & ~ST_MASK) | ST_CMD;  in macii_start()
360  * The VIA Port B output signalling works as follows. After the ADB transceiver
361  * sees a transition on the PB4 and PB5 lines it will crank over the VIA shift
382 		if (via[IFR] & SR_INT)  in macii_interrupt()
383 			via[IFR] = SR_INT;  in macii_interrupt()
390 	status = via[B] & (ST_MASK | CTLR_IRQ);  in macii_interrupt()
402 		x = via[SR];  in macii_interrupt()
418 		via[B] = (via[B] & ~ST_MASK) | ST_EVEN;  in macii_interrupt()
451 			via[ACR] &= ~SR_OUT;  in macii_interrupt()
452 			x = via[SR];  in macii_interrupt()
464 				via[ACR] &= ~SR_OUT;  in macii_interrupt()
465 				x = via[SR];  in macii_interrupt()
474 				via[ACR] &= ~SR_OUT;  in macii_interrupt()
475 				x = via[SR];  in macii_interrupt()
491 			via[SR] = req->data[data_index++];  in macii_interrupt()
494 		if ((via[B] & ST_MASK) == ST_CMD) {  in macii_interrupt()
496 			via[B] = (via[B] & ~ST_MASK) | ST_EVEN;  in macii_interrupt()
499 			via[B] ^= ST_MASK;  in macii_interrupt()
504 		x = via[SR];  in macii_interrupt()
543 		via[B] ^= ST_MASK;  in macii_interrupt()
558 			via[ACR] &= ~SR_OUT;  in macii_interrupt()
559 			x = via[SR];  in macii_interrupt()
560 			via[B] = (via[B] & ~ST_MASK) | ST_IDLE;  in macii_interrupt()