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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 <[email protected]>
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 receiver and its 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_ioremap_resource(ofdev, 0);
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 = platform_get_irq(ofdev, 0);
152 if (irq < 0)
153 return irq;
154
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_obj(*priv->io);
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 strscpy(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 void 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
200static const struct of_device_id apbps2_of_match[] = {
201 { .name = "GAISLER_APBPS2", },
202 { .name = "01_060", },
203 {}
204};
205
206MODULE_DEVICE_TABLE(of, apbps2_of_match);
207
208static struct platform_driver apbps2_of_driver = {
209 .driver = {
210 .name = "grlib-apbps2",
211 .of_match_table = apbps2_of_match,
212 },
213 .probe = apbps2_of_probe,
214 .remove = apbps2_of_remove,
215};
216
217module_platform_driver(apbps2_of_driver);
218
219MODULE_AUTHOR("Aeroflex Gaisler AB.");
220MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
221MODULE_LICENSE("GPL");