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
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 struct resource *res;
136
137 priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
138 if (!priv) {
139 dev_err(&ofdev->dev, "memory allocation failed\n");
140 return -ENOMEM;
141 }
142
143 /* Find Device Address */
144 res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
145 priv->regs = devm_ioremap_resource(&ofdev->dev, res);
146 if (IS_ERR(priv->regs))
147 return PTR_ERR(priv->regs);
148
149 /* Reset hardware, disable interrupt */
150 iowrite32be(0, &priv->regs->ctrl);
151
152 /* IRQ */
153 irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
154 err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
155 IRQF_SHARED, "apbps2", priv);
156 if (err) {
157 dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
158 return err;
159 }
160
161 /* Get core frequency */
162 if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
163 dev_err(&ofdev->dev, "unable to get core frequency\n");
164 return -EINVAL;
165 }
166
167 /* Set reload register to core freq in kHz/10 */
168 iowrite32be(freq_hz / 10000, &priv->regs->reload);
169
170 priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
171 if (!priv->io)
172 return -ENOMEM;
173
174 priv->io->id.type = SERIO_8042;
175 priv->io->open = apbps2_open;
176 priv->io->close = apbps2_close;
177 priv->io->write = apbps2_write;
178 priv->io->port_data = priv;
179 strlcpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
180 snprintf(priv->io->phys, sizeof(priv->io->phys),
181 "apbps2_%d", apbps2_idx++);
182
183 dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
184
185 serio_register_port(priv->io);
186
187 platform_set_drvdata(ofdev, priv);
188
189 return 0;
190 }
191
apbps2_of_remove(struct platform_device * of_dev)192 static int apbps2_of_remove(struct platform_device *of_dev)
193 {
194 struct apbps2_priv *priv = platform_get_drvdata(of_dev);
195
196 serio_unregister_port(priv->io);
197
198 return 0;
199 }
200
201 static const struct of_device_id apbps2_of_match[] = {
202 { .name = "GAISLER_APBPS2", },
203 { .name = "01_060", },
204 {}
205 };
206
207 MODULE_DEVICE_TABLE(of, apbps2_of_match);
208
209 static struct platform_driver apbps2_of_driver = {
210 .driver = {
211 .name = "grlib-apbps2",
212 .of_match_table = apbps2_of_match,
213 },
214 .probe = apbps2_of_probe,
215 .remove = apbps2_of_remove,
216 };
217
218 module_platform_driver(apbps2_of_driver);
219
220 MODULE_AUTHOR("Aeroflex Gaisler AB.");
221 MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
222 MODULE_LICENSE("GPL");
223