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