Input: add driver for Altera PS/2 controller

This patch adds a new SERIO driver to support the Altera University
Program PS/2 controller.

[[e-mail]: assorted cleanups]
Signed-off-by: Thomas Chou <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/serio/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called xilinx_ps2.
 
+config SERIO_ALTERA_PS2
+	tristate "Altera UP PS/2 controller"
+	help
+	  Say Y here if you have Altera University Program PS/2 ports.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called altera_ps2.
+
 endif

drivers/input/serio/Makefile

···
 obj-$(CONFIG_SERIO_LIBPS2)	+= libps2.o
 obj-$(CONFIG_SERIO_RAW)		+= serio_raw.o
 obj-$(CONFIG_SERIO_XILINX_XPS_PS2)	+= xilinx_ps2.o
+obj-$(CONFIG_SERIO_ALTERA_PS2)	+= altera_ps2.o

drivers/input/serio/altera_ps2.c

···
+/*
+ * Altera University Program PS2 controller driver
+ *
+ * Copyright (C) 2008 Thomas Chou <[e-mail]>
+ *
+ * Based on sa1111ps2.c, which is:
+ * Copyright (C) 2002 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#define DRV_NAME "altera_ps2"
+
+struct ps2if {
+	struct serio *io;
+	struct resource *iomem_res;
+	void __iomem *base;
+	unsigned irq;
+};
+
+/*
+ * Read all bytes waiting in the PS2 port.  There should be
+ * at the most one, but we loop for safety.
+ */
+static irqreturn_t altera_ps2_rxint(int irq, void *dev_id)
+{
+	struct ps2if *ps2if = dev_id;
+	unsigned int status;
+	int handled = IRQ_NONE;
+
+	while ((status = readl(ps2if->base)) & 0xffff0000) {
+		serio_interrupt(ps2if->io, status & 0xff, 0);
+		handled = IRQ_HANDLED;
+	}
+
+	return handled;
+}
+
+/*
+ * Write a byte to the PS2 port.
+ */
+static int altera_ps2_write(struct serio *io, unsigned char val)
+{
+	struct ps2if *ps2if = io->port_data;
+
+	writel(val, ps2if->base);
+	return 0;
+}
+
+static int altera_ps2_open(struct serio *io)
+{
+	struct ps2if *ps2if = io->port_data;
+
+	/* clear fifo */
+	while (readl(ps2if->base) & 0xffff0000)
+		/* empty */;
+
+	writel(1, ps2if->base + 4); /* enable rx irq */
+	return 0;
+}
+
+static void altera_ps2_close(struct serio *io)
+{
+	struct ps2if *ps2if = io->port_data;
+
+	writel(0, ps2if->base); /* disable rx irq */
+}
+
+/*
+ * Add one device to this driver.
+ */
+static int altera_ps2_probe(struct platform_device *pdev)
+{
+	struct ps2if *ps2if;
+	struct serio *serio;
+	int error;
+
+	ps2if = kzalloc(sizeof(struct ps2if), GFP_KERNEL);
+	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
+	if (!ps2if || !serio) {
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	serio->id.type		= SERIO_8042;
+	serio->write		= altera_ps2_write;
+	serio->open		= altera_ps2_open;
+	serio->close		= altera_ps2_close;
+	strlcpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
+	strlcpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
+	serio->port_data	= ps2if;
+	serio->dev.parent	= &pdev->dev;
+	ps2if->io		= serio;
+
+	ps2if->iomem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (ps2if->iomem_res == NULL) {
+		error = -ENOENT;
+		goto err_free_mem;
+	}
+
+	ps2if->irq  = platform_get_irq(pdev, 0);
+	if (ps2if->irq < 0) {
+		error = -ENXIO;
+		goto err_free_mem;
+	}
+
+	if (!request_mem_region(ps2if->iomem_res->start,
+				resource_size(ps2if->iomem_res), pdev->name)) {
+		error = -EBUSY;
+		goto err_free_mem;
+	}
+
+	ps2if->base = ioremap(ps2if->iomem_res->start,
+			      resource_size(ps2if->iomem_res));
+	if (!ps2if->base) {
+		error = -ENOMEM;
+		goto err_free_res;
+	}
+
+	error = request_irq(ps2if->irq, altera_ps2_rxint, 0, pdev->name, ps2if);
+	if (error) {
+		dev_err(&pdev->dev, "could not allocate IRQ %d: %d\n",
+			ps2if->irq, error);
+		goto err_unmap;
+	}
+
+	dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, ps2if->irq);
+
+	serio_register_port(ps2if->io);
+	platform_set_drvdata(pdev, ps2if);
+
+	return 0;
+
+ err_unmap:
+	iounmap(ps2if->base);
+ err_free_res:
+	release_mem_region(ps2if->iomem_res->start,
+			   resource_size(ps2if->iomem_res));
+ err_free_mem:
+	kfree(ps2if);
+	kfree(serio);
+	return error;
+}
+
+/*
+ * Remove one device from this driver.
+ */
+static int altera_ps2_remove(struct platform_device *pdev)
+{
+	struct ps2if *ps2if = platform_get_drvdata(pdev);
+
+	platform_set_drvdata(pdev, NULL);
+	serio_unregister_port(ps2if->io);
+	free_irq(ps2if->irq, ps2if);
+	iounmap(ps2if->base);
+	release_mem_region(ps2if->iomem_res->start,
+			   resource_size(ps2if->iomem_res));
+	kfree(ps2if);
+
+	return 0;
+}
+
+/*
+ * Our device driver structure
+ */
+static struct platform_driver altera_ps2_driver = {
+	.probe		= altera_ps2_probe,
+	.remove		= altera_ps2_remove,
+	.driver	= {
+		.name	= DRV_NAME,
+	},
+};
+
+static int __init altera_ps2_init(void)
+{
+	return platform_driver_register(&altera_ps2_driver);
+}
+
+static void __exit altera_ps2_exit(void)
+{
+	platform_driver_unregister(&altera_ps2_driver);
+}
+
+module_init(altera_ps2_init);
+module_exit(altera_ps2_exit);
+
+MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
+MODULE_AUTHOR("Thomas Chou <[e-mail]>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);