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
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	unsigned long tmp;
107
108	/* clear error flags */
109	iowrite32be(0, &priv->regs->status);
110
111	/* Clear old data if available (unlikely) */
112	limit = 1024;
113	while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit)
114		tmp = ioread32be(&priv->regs->data);
115
116	/* Enable reciever and it's interrupt */
117	iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl);
118
119	return 0;
120}
121
122static void apbps2_close(struct serio *io)
123{
124	struct apbps2_priv *priv = io->port_data;
125
126	/* stop interrupts at PS/2 HW level */
127	iowrite32be(0, &priv->regs->ctrl);
128}
129
130/* Initialize one APBPS2 PS/2 core */
131static int apbps2_of_probe(struct platform_device *ofdev)
132{
133	struct apbps2_priv *priv;
134	int irq, err;
135	u32 freq_hz;
136	struct resource *res;
137
138	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
139	if (!priv) {
140		dev_err(&ofdev->dev, "memory allocation failed\n");
141		return -ENOMEM;
142	}
143
144	/* Find Device Address */
145	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
146	priv->regs = devm_ioremap_resource(&ofdev->dev, res);
147	if (IS_ERR(priv->regs))
148		return PTR_ERR(priv->regs);
149
150	/* Reset hardware, disable interrupt */
151	iowrite32be(0, &priv->regs->ctrl);
152
153	/* IRQ */
154	irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
155	err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
156				IRQF_SHARED, "apbps2", priv);
157	if (err) {
158		dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
159		return err;
160	}
161
162	/* Get core frequency */
163	if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
164		dev_err(&ofdev->dev, "unable to get core frequency\n");
165		return -EINVAL;
166	}
167
168	/* Set reload register to core freq in kHz/10 */
169	iowrite32be(freq_hz / 10000, &priv->regs->reload);
170
171	priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
172	if (!priv->io)
173		return -ENOMEM;
174
175	priv->io->id.type = SERIO_8042;
176	priv->io->open = apbps2_open;
177	priv->io->close = apbps2_close;
178	priv->io->write = apbps2_write;
179	priv->io->port_data = priv;
180	strlcpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
181	snprintf(priv->io->phys, sizeof(priv->io->phys),
182		 "apbps2_%d", apbps2_idx++);
183
184	dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
185
186	serio_register_port(priv->io);
187
188	platform_set_drvdata(ofdev, priv);
189
190	return 0;
191}
192
193static int apbps2_of_remove(struct platform_device *of_dev)
194{
195	struct apbps2_priv *priv = platform_get_drvdata(of_dev);
196
197	serio_unregister_port(priv->io);
198
199	return 0;
200}
201
202static const struct of_device_id apbps2_of_match[] = {
203	{ .name = "GAISLER_APBPS2", },
204	{ .name = "01_060", },
205	{}
206};
207
208MODULE_DEVICE_TABLE(of, apbps2_of_match);
209
210static struct platform_driver apbps2_of_driver = {
211	.driver = {
212		.name = "grlib-apbps2",
213		.of_match_table = apbps2_of_match,
214	},
215	.probe = apbps2_of_probe,
216	.remove = apbps2_of_remove,
217};
218
219module_platform_driver(apbps2_of_driver);
220
221MODULE_AUTHOR("Aeroflex Gaisler AB.");
222MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
223MODULE_LICENSE("GPL");
224