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/module.h>
18#include <linux/serio.h>
19#include <linux/errno.h>
20#include <linux/interrupt.h>
21#include <linux/of.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
31struct 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
52struct apbps2_priv {
53	struct serio		*io;
54	struct apbps2_regs	__iomem *regs;
55};
56
57static int apbps2_idx;
58
59static 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
82static 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
102static 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
121static 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 */
130static 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
190static 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
199static const struct of_device_id apbps2_of_match[] = {
200	{ .name = "GAISLER_APBPS2", },
201	{ .name = "01_060", },
202	{}
203};
204
205MODULE_DEVICE_TABLE(of, apbps2_of_match);
206
207static 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
216module_platform_driver(apbps2_of_driver);
217
218MODULE_AUTHOR("Aeroflex Gaisler AB.");
219MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
220MODULE_LICENSE("GPL");
221