1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2013 Aeroflex Gaisler
4  *
5  * This driver supports the APBPS2 PS/2 core available in the GRLIB
6  * VHDL IP core library.
7  *
8  * Full documentation of the APBPS2 core can be found here:
9  * http://www.gaisler.com/products/grlib/grip.pdf
10  *
11  * See "Documentation/devicetree/bindings/input/ps2keyb-mouse-apbps2.txt" for
12  * information on open firmware properties.
13  *
14  * Contributors: Daniel Hellstrom <daniel@gaisler.com>
15  */
16 #include <linux/platform_device.h>
17 #include <linux/of_device.h>
18 #include <linux/module.h>
19 #include <linux/serio.h>
20 #include <linux/errno.h>
21 #include <linux/interrupt.h>
22 #include <linux/of_irq.h>
23 #include <linux/device.h>
24 #include <linux/delay.h>
25 #include <linux/err.h>
26 #include <linux/slab.h>
27 #include <linux/string.h>
28 #include <linux/kernel.h>
29 #include <linux/io.h>
30 
31 struct apbps2_regs {
32 	u32 __iomem data;	/* 0x00 */
33 	u32 __iomem status;	/* 0x04 */
34 	u32 __iomem ctrl;	/* 0x08 */
35 	u32 __iomem reload;	/* 0x0c */
36 };
37 
38 #define APBPS2_STATUS_DR	(1<<0)
39 #define APBPS2_STATUS_PE	(1<<1)
40 #define APBPS2_STATUS_FE	(1<<2)
41 #define APBPS2_STATUS_KI	(1<<3)
42 #define APBPS2_STATUS_RF	(1<<4)
43 #define APBPS2_STATUS_TF	(1<<5)
44 #define APBPS2_STATUS_TCNT	(0x1f<<22)
45 #define APBPS2_STATUS_RCNT	(0x1f<<27)
46 
47 #define APBPS2_CTRL_RE		(1<<0)
48 #define APBPS2_CTRL_TE		(1<<1)
49 #define APBPS2_CTRL_RI		(1<<2)
50 #define APBPS2_CTRL_TI		(1<<3)
51 
52 struct apbps2_priv {
53 	struct serio		*io;
54 	struct apbps2_regs	__iomem *regs;
55 };
56 
57 static int apbps2_idx;
58 
apbps2_isr(int irq,void * dev_id)59 static irqreturn_t apbps2_isr(int irq, void *dev_id)
60 {
61 	struct apbps2_priv *priv = dev_id;
62 	unsigned long status, data, rxflags;
63 	irqreturn_t ret = IRQ_NONE;
64 
65 	while ((status = ioread32be(&priv->regs->status)) & APBPS2_STATUS_DR) {
66 		data = ioread32be(&priv->regs->data);
67 		rxflags = (status & APBPS2_STATUS_PE) ? SERIO_PARITY : 0;
68 		rxflags |= (status & APBPS2_STATUS_FE) ? SERIO_FRAME : 0;
69 
70 		/* clear error bits? */
71 		if (rxflags)
72 			iowrite32be(0, &priv->regs->status);
73 
74 		serio_interrupt(priv->io, data, rxflags);
75 
76 		ret = IRQ_HANDLED;
77 	}
78 
79 	return ret;
80 }
81 
apbps2_write(struct serio * io,unsigned char val)82 static int apbps2_write(struct serio *io, unsigned char val)
83 {
84 	struct apbps2_priv *priv = io->port_data;
85 	unsigned int tleft = 10000; /* timeout in 100ms */
86 
87 	/* delay until PS/2 controller has room for more chars */
88 	while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) && tleft--)
89 		udelay(10);
90 
91 	if ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) == 0) {
92 		iowrite32be(val, &priv->regs->data);
93 
94 		iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI | APBPS2_CTRL_TE,
95 				&priv->regs->ctrl);
96 		return 0;
97 	}
98 
99 	return -ETIMEDOUT;
100 }
101 
apbps2_open(struct serio * io)102 static int apbps2_open(struct serio *io)
103 {
104 	struct apbps2_priv *priv = io->port_data;
105 	int limit;
106 
107 	/* clear error flags */
108 	iowrite32be(0, &priv->regs->status);
109 
110 	/* Clear old data if available (unlikely) */
111 	limit = 1024;
112 	while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit)
113 		ioread32be(&priv->regs->data);
114 
115 	/* Enable reciever and it's interrupt */
116 	iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl);
117 
118 	return 0;
119 }
120 
apbps2_close(struct serio * io)121 static void apbps2_close(struct serio *io)
122 {
123 	struct apbps2_priv *priv = io->port_data;
124 
125 	/* stop interrupts at PS/2 HW level */
126 	iowrite32be(0, &priv->regs->ctrl);
127 }
128 
129 /* Initialize one APBPS2 PS/2 core */
apbps2_of_probe(struct platform_device * ofdev)130 static int apbps2_of_probe(struct platform_device *ofdev)
131 {
132 	struct apbps2_priv *priv;
133 	int irq, err;
134 	u32 freq_hz;
135 
136 	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
137 	if (!priv) {
138 		dev_err(&ofdev->dev, "memory allocation failed\n");
139 		return -ENOMEM;
140 	}
141 
142 	/* Find Device Address */
143 	priv->regs = devm_platform_get_and_ioremap_resource(ofdev, 0, NULL);
144 	if (IS_ERR(priv->regs))
145 		return PTR_ERR(priv->regs);
146 
147 	/* Reset hardware, disable interrupt */
148 	iowrite32be(0, &priv->regs->ctrl);
149 
150 	/* IRQ */
151 	irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
152 	err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
153 				IRQF_SHARED, "apbps2", priv);
154 	if (err) {
155 		dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
156 		return err;
157 	}
158 
159 	/* Get core frequency */
160 	if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
161 		dev_err(&ofdev->dev, "unable to get core frequency\n");
162 		return -EINVAL;
163 	}
164 
165 	/* Set reload register to core freq in kHz/10 */
166 	iowrite32be(freq_hz / 10000, &priv->regs->reload);
167 
168 	priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
169 	if (!priv->io)
170 		return -ENOMEM;
171 
172 	priv->io->id.type = SERIO_8042;
173 	priv->io->open = apbps2_open;
174 	priv->io->close = apbps2_close;
175 	priv->io->write = apbps2_write;
176 	priv->io->port_data = priv;
177 	strscpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
178 	snprintf(priv->io->phys, sizeof(priv->io->phys),
179 		 "apbps2_%d", apbps2_idx++);
180 
181 	dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
182 
183 	serio_register_port(priv->io);
184 
185 	platform_set_drvdata(ofdev, priv);
186 
187 	return 0;
188 }
189 
apbps2_of_remove(struct platform_device * of_dev)190 static int apbps2_of_remove(struct platform_device *of_dev)
191 {
192 	struct apbps2_priv *priv = platform_get_drvdata(of_dev);
193 
194 	serio_unregister_port(priv->io);
195 
196 	return 0;
197 }
198 
199 static const struct of_device_id apbps2_of_match[] = {
200 	{ .name = "GAISLER_APBPS2", },
201 	{ .name = "01_060", },
202 	{}
203 };
204 
205 MODULE_DEVICE_TABLE(of, apbps2_of_match);
206 
207 static struct platform_driver apbps2_of_driver = {
208 	.driver = {
209 		.name = "grlib-apbps2",
210 		.of_match_table = apbps2_of_match,
211 	},
212 	.probe = apbps2_of_probe,
213 	.remove = apbps2_of_remove,
214 };
215 
216 module_platform_driver(apbps2_of_driver);
217 
218 MODULE_AUTHOR("Aeroflex Gaisler AB.");
219 MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
220 MODULE_LICENSE("GPL");
221