3  * Device driver for the via ADB on (many) Mac II-class machines
21  *   Rockwell R6522 VIA datasheet
37 static volatile unsigned char *via;  variable
39 /* VIA registers - spaced 0x200 bytes apart */
120 static int status;          /* VIA's ADB status bits captured upon interrupt */
134 	via = via1;  in macii_probe()
169 	via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;  in macii_init_via()
172 	via[B] |= ST_IDLE;  in macii_init_via()
175 	via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;  in macii_init_via()
178 	x = via[SR];  in macii_init_via()
339 	via[ACR] |= SR_OUT;  in macii_start()
341 	via[SR] = req->data[1];  in macii_start()
343 	via[B] = (via[B] & ~ST_MASK) | ST_CMD;  in macii_start()
358  * The VIA Port B output signalling works as follows. After the ADB transceiver
359  * sees a transition on the PB4 and PB5 lines it will crank over the VIA shift
380 		if (via[IFR] & SR_INT)  in macii_interrupt()
381 			via[IFR] = SR_INT;  in macii_interrupt()
388 	status = via[B] & (ST_MASK | CTLR_IRQ);  in macii_interrupt()
400 		x = via[SR];  in macii_interrupt()
416 		via[B] = (via[B] & ~ST_MASK) | ST_EVEN;  in macii_interrupt()
449 			via[ACR] &= ~SR_OUT;  in macii_interrupt()
450 			x = via[SR];  in macii_interrupt()
462 				via[ACR] &= ~SR_OUT;  in macii_interrupt()
463 				x = via[SR];  in macii_interrupt()
472 				via[ACR] &= ~SR_OUT;  in macii_interrupt()
473 				x = via[SR];  in macii_interrupt()
489 			via[SR] = req->data[data_index++];  in macii_interrupt()
492 		if ((via[B] & ST_MASK) == ST_CMD) {  in macii_interrupt()
494 			via[B] = (via[B] & ~ST_MASK) | ST_EVEN;  in macii_interrupt()
497 			via[B] ^= ST_MASK;  in macii_interrupt()
502 		x = via[SR];  in macii_interrupt()
541 		via[B] ^= ST_MASK;  in macii_interrupt()
556 			via[ACR] &= ~SR_OUT;  in macii_interrupt()
557 			x = via[SR];  in macii_interrupt()
558 			via[B] = (via[B] & ~ST_MASK) | ST_IDLE;  in macii_interrupt()