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
31 struct 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
52 struct apbps2_priv {
53 struct serio *io;
54 struct apbps2_regs __iomem *regs;
55 };
56
57 static int apbps2_idx;
58
apbps2_isr(int irq,void * dev_id)59 static 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
apbps2_write(struct serio * io,unsigned char val)82 static 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
apbps2_open(struct serio * io)102 static 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
apbps2_close(struct serio * io)121 static 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 */
apbps2_of_probe(struct platform_device * ofdev)130 static 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
apbps2_of_remove(struct platform_device * of_dev)190 static 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
199 static const struct of_device_id apbps2_of_match[] = {
200 { .name = "GAISLER_APBPS2", },
201 { .name = "01_060", },
202 {}
203 };
204
205 MODULE_DEVICE_TABLE(of, apbps2_of_match);
206
207 static 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
216 module_platform_driver(apbps2_of_driver);
217
218 MODULE_AUTHOR("Aeroflex Gaisler AB.");
219 MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
220 MODULE_LICENSE("GPL");
221