input/serio/altera_ps2.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Altera University Program PS2 controller driver
0004  *
0005  * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
0006  *
0007  * Based on sa1111ps2.c, which is:
0008  * Copyright (C) 2002 Russell King
0009  */
0010
0011 #include <linux/module.h>
0012 #include <linux/input.h>
0013 #include <linux/serio.h>
0014 #include <linux/interrupt.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/io.h>
0017 #include <linux/slab.h>
0018 #include <linux/of.h>
0019
0020 #define DRV_NAME "altera_ps2"
0021
0022 struct ps2if {
0023     struct serio *io;
0024     void __iomem *base;
0025 };
0026
0027 /*
0028  * Read all bytes waiting in the PS2 port.  There should be
0029  * at the most one, but we loop for safety.
0030  */
0031 static irqreturn_t altera_ps2_rxint(int irq, void *dev_id)
0032 {
0033     struct ps2if *ps2if = dev_id;
0034     unsigned int status;
0035     irqreturn_t handled = IRQ_NONE;
0036
0037     while ((status = readl(ps2if->base)) & 0xffff0000) {
0038         serio_interrupt(ps2if->io, status & 0xff, 0);
0039         handled = IRQ_HANDLED;
0040     }
0041
0042     return handled;
0043 }
0044
0045 /*
0046  * Write a byte to the PS2 port.
0047  */
0048 static int altera_ps2_write(struct serio *io, unsigned char val)
0049 {
0050     struct ps2if *ps2if = io->port_data;
0051
0052     writel(val, ps2if->base);
0053     return 0;
0054 }
0055
0056 static int altera_ps2_open(struct serio *io)
0057 {
0058     struct ps2if *ps2if = io->port_data;
0059
0060     /* clear fifo */
0061     while (readl(ps2if->base) & 0xffff0000)
0062         /* empty */;
0063
0064     writel(1, ps2if->base + 4); /* enable rx irq */
0065     return 0;
0066 }
0067
0068 static void altera_ps2_close(struct serio *io)
0069 {
0070     struct ps2if *ps2if = io->port_data;
0071
0072     writel(0, ps2if->base + 4); /* disable rx irq */
0073 }
0074
0075 /*
0076  * Add one device to this driver.
0077  */
0078 static int altera_ps2_probe(struct platform_device *pdev)
0079 {
0080     struct ps2if *ps2if;
0081     struct resource *res;
0082     struct serio *serio;
0083     int error, irq;
0084
0085     ps2if = devm_kzalloc(&pdev->dev, sizeof(struct ps2if), GFP_KERNEL);
0086     if (!ps2if)
0087         return -ENOMEM;
0088
0089     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
0090     ps2if->base = devm_ioremap_resource(&pdev->dev, res);
0091     if (IS_ERR(ps2if->base))
0092         return PTR_ERR(ps2if->base);
0093
0094     irq = platform_get_irq(pdev, 0);
0095     if (irq < 0)
0096         return -ENXIO;
0097
0098     error = devm_request_irq(&pdev->dev, irq, altera_ps2_rxint, 0,
0099                  pdev->name, ps2if);
0100     if (error) {
0101         dev_err(&pdev->dev, "could not request IRQ %d\n", irq);
0102         return error;
0103     }
0104
0105     serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
0106     if (!serio)
0107         return -ENOMEM;
0108
0109     serio->id.type      = SERIO_8042;
0110     serio->write        = altera_ps2_write;
0111     serio->open     = altera_ps2_open;
0112     serio->close        = altera_ps2_close;
0113     strlcpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
0114     strlcpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
0115     serio->port_data    = ps2if;
0116     serio->dev.parent   = &pdev->dev;
0117     ps2if->io       = serio;
0118
0119     dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, irq);
0120
0121     serio_register_port(ps2if->io);
0122     platform_set_drvdata(pdev, ps2if);
0123
0124     return 0;
0125 }
0126
0127 /*
0128  * Remove one device from this driver.
0129  */
0130 static int altera_ps2_remove(struct platform_device *pdev)
0131 {
0132     struct ps2if *ps2if = platform_get_drvdata(pdev);
0133
0134     serio_unregister_port(ps2if->io);
0135
0136     return 0;
0137 }
0138
0139 #ifdef CONFIG_OF
0140 static const struct of_device_id altera_ps2_match[] = {
0141     { .compatible = "ALTR,ps2-1.0", },
0142     { .compatible = "altr,ps2-1.0", },
0143     {},
0144 };
0145 MODULE_DEVICE_TABLE(of, altera_ps2_match);
0146 #endif /* CONFIG_OF */
0147
0148 /*
0149  * Our device driver structure
0150  */
0151 static struct platform_driver altera_ps2_driver = {
0152     .probe      = altera_ps2_probe,
0153     .remove     = altera_ps2_remove,
0154     .driver = {
0155         .name   = DRV_NAME,
0156         .of_match_table = of_match_ptr(altera_ps2_match),
0157     },
0158 };
0159 module_platform_driver(altera_ps2_driver);
0160
0161 MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
0162 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
0163 MODULE_LICENSE("GPL");
0164 MODULE_ALIAS("platform:" DRV_NAME);