1 // SPDX-License-Identifier: GPL-2.0-only
2 /* display7seg.c - Driver implementation for the 7-segment display
32 /* Solaris compatibility flag -
34  * documented driver features (ref Sun doc 806-0180-03).  
38  * 	1) Device ALWAYS reverts to OBP-specified FLIPPED mode
41  * 	   FLIP bit
44  * omitting above features, set this parameter to non-zero.
51 MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500");
61  * Register block address- see header for details
62  * -----------------------------------------
63  * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |
64  * -----------------------------------------
66  * DP 		- Toggles decimal point on/off 
67  * ALARM	- Toggles "Alarm" LED green/red
68  * FLIP		- Inverts display for upside-down mounted board
69  * bits 0-4	- 7-segment display contents
76 		return -ENODEV;  in d7s_open()
85 	 * are not operating in solaris-compat mode  in d7s_release()
91 		regval = readb(p->regs);  in d7s_release()
92 		if (p->flipped)  in d7s_release()
96 		writeb(regval, p->regs);  in d7s_release()
105 	u8 regs = readb(p->regs);  in d7s_ioctl()
110 		return -ENODEV;  in d7s_ioctl()
115 		/* assign device register values we mask-out D7S_FLIP  in d7s_ioctl()
119 			error = -EFAULT;  in d7s_ioctl()
128 		writeb(ireg, p->regs);  in d7s_ioctl()
139 			error = -EFAULT;  in d7s_ioctl()
145 		/* toggle device mode-- flip display orientation */  in d7s_ioctl()
147 		writeb(regs, p->regs);  in d7s_ioctl()
173 	int err = -EINVAL;  in d7s_probe()
180 	p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);  in d7s_probe()
181 	err = -ENOMEM;  in d7s_probe()
185 	p->regs = of_ioremap(&op->resource[0], 0, sizeof(u8), "d7s");  in d7s_probe()
186 	if (!p->regs) {  in d7s_probe()
187 		printk(KERN_ERR PFX "Cannot map chip registers\n");  in d7s_probe()
198 	/* OBP option "d7s-flipped?" is honored as default for the  in d7s_probe()
201 	regs = readb(p->regs);  in d7s_probe()
204 	    p->flipped = of_property_read_bool(opts, "d7s-flipped?");  in d7s_probe()
206 	if (p->flipped)  in d7s_probe()
211 	writeb(regs,  p->regs);  in d7s_probe()
213 	printk(KERN_INFO PFX "7-Segment Display%pOF at [%s:0x%llx] %s\n",  in d7s_probe()
214 	       op->dev.of_node,  in d7s_probe()
216 	       op->resource[0].start,  in d7s_probe()
219 	dev_set_drvdata(&op->dev, p);  in d7s_probe()
228 	of_iounmap(&op->resource[0], p->regs, sizeof(u8));  in d7s_probe()
234 	struct d7s *p = dev_get_drvdata(&op->dev);  in d7s_remove()
235 	u8 regs = readb(p->regs);  in d7s_remove()
237 	/* Honor OBP d7s-flipped? unless operating in solaris-compat mode */  in d7s_remove()
239 		if (p->flipped)  in d7s_remove()
243 		writeb(regs, p->regs);  in d7s_remove()
247 	of_iounmap(&op->resource[0], p->regs, sizeof(u8));  in d7s_remove()