drivers/input/serio/ambakmi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  linux/drivers/input/serio/ambakmi.c
 *
 *  Copyright (C) 2000-2003 Deep Blue Solutions Ltd.
 *  Copyright (C) 2002 Russell King.
 */
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/amba/bus.h>
#include <linux/amba/kmi.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/irq.h>

#define KMI_BASE	(kmi->base)

struct amba_kmi_port {
	struct serio		*io;
	struct clk		*clk;
	void __iomem		*base;
	unsigned int		irq;
	unsigned int		divisor;
	unsigned int		open;
};

static irqreturn_t amba_kmi_int(int irq, void *dev_id)
{
	struct amba_kmi_port *kmi = dev_id;
	unsigned int status = readb(KMIIR);
	int handled = IRQ_NONE;

	while (status & KMIIR_RXINTR) {
		serio_interrupt(kmi->io, readb(KMIDATA), 0);
		status = readb(KMIIR);
		handled = IRQ_HANDLED;
	}

	return handled;
}

static int amba_kmi_write(struct serio *io, unsigned char val)
{
	struct amba_kmi_port *kmi = io->port_data;
	unsigned int timeleft = 10000; /* timeout in 100ms */

	while ((readb(KMISTAT) & KMISTAT_TXEMPTY) == 0 && --timeleft)
		udelay(10);

	if (timeleft)
		writeb(val, KMIDATA);

	return timeleft ? 0 : SERIO_TIMEOUT;
}

static int amba_kmi_open(struct serio *io)
{
	struct amba_kmi_port *kmi = io->port_data;
	unsigned int divisor;
	int ret;

	ret = clk_prepare_enable(kmi->clk);
	if (ret)
		goto out;

	divisor = clk_get_rate(kmi->clk) / 8000000 - 1;
	writeb(divisor, KMICLKDIV);
	writeb(KMICR_EN, KMICR);

	ret = request_irq(kmi->irq, amba_kmi_int, IRQF_SHARED, "kmi-pl050",
			  kmi);
	if (ret) {
		printk(KERN_ERR "kmi: failed to claim IRQ%d\n", kmi->irq);
		writeb(0, KMICR);
		goto clk_disable;
	}

	writeb(KMICR_EN | KMICR_RXINTREN, KMICR);

	return 0;

 clk_disable:
	clk_disable_unprepare(kmi->clk);
 out:
	return ret;
}

static void amba_kmi_close(struct serio *io)
{
	struct amba_kmi_port *kmi = io->port_data;

	writeb(0, KMICR);

	free_irq(kmi->irq, kmi);
	clk_disable_unprepare(kmi->clk);
}

static int amba_kmi_probe(struct amba_device *dev,
	const struct amba_id *id)
{
	struct amba_kmi_port *kmi;
	struct serio *io;
	int ret;

	ret = amba_request_regions(dev, NULL);
	if (ret)
		return ret;

	kmi = kzalloc(sizeof(struct amba_kmi_port), GFP_KERNEL);
	io = kzalloc(sizeof(struct serio), GFP_KERNEL);
	if (!kmi || !io) {
		ret = -ENOMEM;
		goto out;
	}


	io->id.type	= SERIO_8042;
	io->write	= amba_kmi_write;
	io->open	= amba_kmi_open;
	io->close	= amba_kmi_close;
	strlcpy(io->name, dev_name(&dev->dev), sizeof(io->name));
	strlcpy(io->phys, dev_name(&dev->dev), sizeof(io->phys));
	io->port_data	= kmi;
	io->dev.parent	= &dev->dev;

	kmi->io		= io;
	kmi->base	= ioremap(dev->res.start, resource_size(&dev->res));
	if (!kmi->base) {
		ret = -ENOMEM;
		goto out;
	}

	kmi->clk = clk_get(&dev->dev, "KMIREFCLK");
	if (IS_ERR(kmi->clk)) {
		ret = PTR_ERR(kmi->clk);
		goto unmap;
	}

	kmi->irq = dev->irq[0];
	amba_set_drvdata(dev, kmi);

	serio_register_port(kmi->io);
	return 0;

 unmap:
	iounmap(kmi->base);
 out:
	kfree(kmi);
	kfree(io);
	amba_release_regions(dev);
	return ret;
}

static void amba_kmi_remove(struct amba_device *dev)
{
	struct amba_kmi_port *kmi = amba_get_drvdata(dev);

	serio_unregister_port(kmi->io);
	clk_put(kmi->clk);
	iounmap(kmi->base);
	kfree(kmi);
	amba_release_regions(dev);
}

static int __maybe_unused amba_kmi_resume(struct device *dev)
{
	struct amba_kmi_port *kmi = dev_get_drvdata(dev);

	/* kick the serio layer to rescan this port */
	serio_reconnect(kmi->io);

	return 0;
}

static SIMPLE_DEV_PM_OPS(amba_kmi_dev_pm_ops, NULL, amba_kmi_resume);

static const struct amba_id amba_kmi_idtable[] = {
	{
		.id	= 0x00041050,
		.mask	= 0x000fffff,
	},
	{ 0, 0 }
};

MODULE_DEVICE_TABLE(amba, amba_kmi_idtable);

static struct amba_driver ambakmi_driver = {
	.drv		= {
		.name	= "kmi-pl050",
		.owner	= THIS_MODULE,
		.pm	= &amba_kmi_dev_pm_ops,
	},
	.id_table	= amba_kmi_idtable,
	.probe		= amba_kmi_probe,
	.remove		= amba_kmi_remove,
};

module_amba_driver(ambakmi_driver);

MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
MODULE_DESCRIPTION("AMBA KMI controller driver");
MODULE_LICENSE("GPL");