1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* ------------------------------------------------------------------------ *
3  * i2c-parport.c I2C bus over parallel port                                 *
4  * ------------------------------------------------------------------------ *
5    Copyright (C) 2003-2011 Jean Delvare <jdelvare@suse.de>
7    Based on older i2c-philips-par.c driver
8    Copyright (C) 1995-2000 Simon G. Vogl
13  * ------------------------------------------------------------------------ */
15 #define pr_fmt(fmt) "i2c-parport: " fmt
22 #include <linux/i2c.h>
23 #include <linux/i2c-algo-bit.h>
24 #include <linux/i2c-smbus.h>
89 	/* type 6: Barco LPT->DVI (K5800236) adapter */
104 	/* type 8: VCT-jig */
113 /* ----- Device list ------------------------------------------------------ */
128 static int parport[MAX_DEVICE] = {0, -1, -1, -1};
136 static int type = -1;
146 	" 6 = Barco LPT->DVI (K5800236) adapter\n"
148 	" 8 = VCT-jig\n"
151 /* ----- Low-level parallel port access ----------------------------------- */
190 /* ----- Unified line operation functions --------------------------------- */
195 	u8 oldval = port_read[op->port](data);  in line_set()
198 	if ((op->inverted && !state) || (!op->inverted && state))  in line_set()
199 		port_write[op->port](data, oldval | op->val);  in line_set()
201 		port_write[op->port](data, oldval & ~op->val);  in line_set()
207 	u8 oldval = port_read[op->port](data);  in line_get()
209 	return ((op->inverted && (oldval & op->val) != op->val)  in line_get()
210 	    || (!op->inverted && (oldval & op->val) == op->val));  in line_get()
213 /* ----- I2C algorithm call-back functions and structures ----------------- */
238    cannot read SCL back, and will also make the data field point to
246 	.timeout	= HZ,
249 /* ----- I2c and parallel port call-back functions and structures --------- */
254 	struct i2c_client *ara = adapter->ara;  in i2c_parport_irq()
257 		dev_dbg(&ara->dev, "SMBus alert received\n");  in i2c_parport_irq()
260 		dev_dbg(&adapter->adapter.dev,  in i2c_parport_irq()
281 		if (parport[i] == -1)  in i2c_parport_attach()
283 		if (port->number == parport[i])  in i2c_parport_attach()
287 		pr_debug("Not using parport%d.\n", port->number);  in i2c_parport_attach()
299 	pr_debug("attaching to %s\n", port->name);  in i2c_parport_attach()
301 	adapter->pdev = parport_register_dev_model(port, "i2c-parport",  in i2c_parport_attach()
303 	if (!adapter->pdev) {  in i2c_parport_attach()
309 	adapter->adapter.owner = THIS_MODULE;  in i2c_parport_attach()
310 	adapter->adapter.class = I2C_CLASS_HWMON;  in i2c_parport_attach()
311 	strscpy(adapter->adapter.name, "Parallel port adapter",  in i2c_parport_attach()
312 		sizeof(adapter->adapter.name));  in i2c_parport_attach()
313 	adapter->algo_data = parport_algo_data;  in i2c_parport_attach()
314 	/* Slow down if we can't sense SCL */  in i2c_parport_attach()
316 		adapter->algo_data.getscl = NULL;  in i2c_parport_attach()
317 		adapter->algo_data.udelay = 50; /* ~10 kbps */  in i2c_parport_attach()
319 	adapter->algo_data.data = port;  in i2c_parport_attach()
320 	adapter->adapter.algo_data = &adapter->algo_data;  in i2c_parport_attach()
321 	adapter->adapter.dev.parent = port->physport->dev;  in i2c_parport_attach()
323 	if (parport_claim_or_block(adapter->pdev) < 0) {  in i2c_parport_attach()
324 		dev_err(&adapter->pdev->dev,  in i2c_parport_attach()
329 	/* Reset hardware to a sane state (SCL and SDA high) */  in i2c_parport_attach()
339 	if (i2c_bit_add_bus(&adapter->adapter) < 0) {  in i2c_parport_attach()
340 		dev_err(&adapter->pdev->dev, "Unable to register with I2C\n");  in i2c_parport_attach()
348 		ara = i2c_new_smbus_alert_device(&adapter->adapter,  in i2c_parport_attach()
349 						 &adapter->alert_data);  in i2c_parport_attach()
351 			adapter->ara = ara;  in i2c_parport_attach()
354 			dev_warn(&adapter->pdev->dev,  in i2c_parport_attach()
361 	list_add_tail(&adapter->node, &adapter_list);  in i2c_parport_attach()
366 	parport_release(adapter->pdev);  in i2c_parport_attach()
367 	parport_unregister_device(adapter->pdev);  in i2c_parport_attach()
379 		if (adapter->pdev->port == port) {  in i2c_parport_detach()
380 			if (adapter->ara) {  in i2c_parport_detach()
382 				i2c_unregister_device(adapter->ara);  in i2c_parport_detach()
384 			i2c_del_adapter(&adapter->adapter);  in i2c_parport_detach()
386 			/* Un-init if needed (power off...) */  in i2c_parport_detach()
390 			parport_release(adapter->pdev);  in i2c_parport_detach()
391 			parport_unregister_device(adapter->pdev);  in i2c_parport_detach()
392 			list_del(&adapter->node);  in i2c_parport_detach()
400 	.name = "i2c-parport",
407 MODULE_DESCRIPTION("I2C bus over parallel port");