1/*
2 * Copyright (C) 2013 Aeroflex Gaisler
3 *
4 * This driver supports the APBPS2 PS/2 core available in the GRLIB
5 * VHDL IP core library.
6 *
7 * Full documentation of the APBPS2 core can be found here:
8 * http://www.gaisler.com/products/grlib/grip.pdf
9 *
10 * See "Documentation/devicetree/bindings/input/ps2keyb-mouse-apbps2.txt" for
11 * information on open firmware properties.
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * Contributors: Daniel Hellstrom <daniel@gaisler.com>
19 */
20#include <linux/platform_device.h>
21#include <linux/of_device.h>
22#include <linux/module.h>
23#include <linux/serio.h>
24#include <linux/errno.h>
25#include <linux/interrupt.h>
26#include <linux/of_irq.h>
27#include <linux/device.h>
28#include <linux/delay.h>
29#include <linux/err.h>
30#include <linux/slab.h>
31#include <linux/string.h>
32#include <linux/kernel.h>
33#include <linux/io.h>
34
35struct apbps2_regs {
36	u32 __iomem data;	/* 0x00 */
37	u32 __iomem status;	/* 0x04 */
38	u32 __iomem ctrl;	/* 0x08 */
39	u32 __iomem reload;	/* 0x0c */
40};
41
42#define APBPS2_STATUS_DR	(1<<0)
43#define APBPS2_STATUS_PE	(1<<1)
44#define APBPS2_STATUS_FE	(1<<2)
45#define APBPS2_STATUS_KI	(1<<3)
46#define APBPS2_STATUS_RF	(1<<4)
47#define APBPS2_STATUS_TF	(1<<5)
48#define APBPS2_STATUS_TCNT	(0x1f<<22)
49#define APBPS2_STATUS_RCNT	(0x1f<<27)
50
51#define APBPS2_CTRL_RE		(1<<0)
52#define APBPS2_CTRL_TE		(1<<1)
53#define APBPS2_CTRL_RI		(1<<2)
54#define APBPS2_CTRL_TI		(1<<3)
55
56struct apbps2_priv {
57	struct serio		*io;
58	struct apbps2_regs	*regs;
59};
60
61static int apbps2_idx;
62
63static irqreturn_t apbps2_isr(int irq, void *dev_id)
64{
65	struct apbps2_priv *priv = dev_id;
66	unsigned long status, data, rxflags;
67	irqreturn_t ret = IRQ_NONE;
68
69	while ((status = ioread32be(&priv->regs->status)) & APBPS2_STATUS_DR) {
70		data = ioread32be(&priv->regs->data);
71		rxflags = (status & APBPS2_STATUS_PE) ? SERIO_PARITY : 0;
72		rxflags |= (status & APBPS2_STATUS_FE) ? SERIO_FRAME : 0;
73
74		/* clear error bits? */
75		if (rxflags)
76			iowrite32be(0, &priv->regs->status);
77
78		serio_interrupt(priv->io, data, rxflags);
79
80		ret = IRQ_HANDLED;
81	}
82
83	return ret;
84}
85
86static int apbps2_write(struct serio *io, unsigned char val)
87{
88	struct apbps2_priv *priv = io->port_data;
89	unsigned int tleft = 10000; /* timeout in 100ms */
90
91	/* delay until PS/2 controller has room for more chars */
92	while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) && tleft--)
93		udelay(10);
94
95	if ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) == 0) {
96		iowrite32be(val, &priv->regs->data);
97
98		iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI | APBPS2_CTRL_TE,
99				&priv->regs->ctrl);
100		return 0;
101	}
102
103	return -ETIMEDOUT;
104}
105
106static int apbps2_open(struct serio *io)
107{
108	struct apbps2_priv *priv = io->port_data;
109	int limit;
110	unsigned long tmp;
111
112	/* clear error flags */
113	iowrite32be(0, &priv->regs->status);
114
115	/* Clear old data if available (unlikely) */
116	limit = 1024;
117	while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit)
118		tmp = ioread32be(&priv->regs->data);
119
120	/* Enable reciever and it's interrupt */
121	iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl);
122
123	return 0;
124}
125
126static void apbps2_close(struct serio *io)
127{
128	struct apbps2_priv *priv = io->port_data;
129
130	/* stop interrupts at PS/2 HW level */
131	iowrite32be(0, &priv->regs->ctrl);
132}
133
134/* Initialize one APBPS2 PS/2 core */
135static int apbps2_of_probe(struct platform_device *ofdev)
136{
137	struct apbps2_priv *priv;
138	int irq, err;
139	u32 freq_hz;
140	struct resource *res;
141
142	priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
143	if (!priv) {
144		dev_err(&ofdev->dev, "memory allocation failed\n");
145		return -ENOMEM;
146	}
147
148	/* Find Device Address */
149	res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
150	priv->regs = devm_ioremap_resource(&ofdev->dev, res);
151	if (IS_ERR(priv->regs))
152		return PTR_ERR(priv->regs);
153
154	/* Reset hardware, disable interrupt */
155	iowrite32be(0, &priv->regs->ctrl);
156
157	/* IRQ */
158	irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
159	err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
160				IRQF_SHARED, "apbps2", priv);
161	if (err) {
162		dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
163		return err;
164	}
165
166	/* Get core frequency */
167	if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
168		dev_err(&ofdev->dev, "unable to get core frequency\n");
169		return -EINVAL;
170	}
171
172	/* Set reload register to core freq in kHz/10 */
173	iowrite32be(freq_hz / 10000, &priv->regs->reload);
174
175	priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
176	if (!priv->io)
177		return -ENOMEM;
178
179	priv->io->id.type = SERIO_8042;
180	priv->io->open = apbps2_open;
181	priv->io->close = apbps2_close;
182	priv->io->write = apbps2_write;
183	priv->io->port_data = priv;
184	strlcpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
185	snprintf(priv->io->phys, sizeof(priv->io->phys),
186		 "apbps2_%d", apbps2_idx++);
187
188	dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
189
190	serio_register_port(priv->io);
191
192	platform_set_drvdata(ofdev, priv);
193
194	return 0;
195}
196
197static int apbps2_of_remove(struct platform_device *of_dev)
198{
199	struct apbps2_priv *priv = platform_get_drvdata(of_dev);
200
201	serio_unregister_port(priv->io);
202
203	return 0;
204}
205
206static const struct of_device_id apbps2_of_match[] = {
207	{ .name = "GAISLER_APBPS2", },
208	{ .name = "01_060", },
209	{}
210};
211
212MODULE_DEVICE_TABLE(of, apbps2_of_match);
213
214static struct platform_driver apbps2_of_driver = {
215	.driver = {
216		.name = "grlib-apbps2",
217		.of_match_table = apbps2_of_match,
218	},
219	.probe = apbps2_of_probe,
220	.remove = apbps2_of_remove,
221};
222
223module_platform_driver(apbps2_of_driver);
224
225MODULE_AUTHOR("Aeroflex Gaisler AB.");
226MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
227MODULE_LICENSE("GPL");
228