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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2013 Aeroflex Gaisler
*
* This driver supports the APBPS2 PS/2 core available in the GRLIB
* VHDL IP core library.
*
* Full documentation of the APBPS2 core can be found here:
* http://www.gaisler.com/products/grlib/grip.pdf
*
* See "Documentation/devicetree/bindings/input/ps2keyb-mouse-apbps2.txt" for
* information on open firmware properties.
*
* Contributors: Daniel Hellstrom <daniel@gaisler.com>
*/
#include <linux/platform_device.h>
#include <linux/of_device.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/io.h>
struct apbps2_regs {
u32 __iomem data; /* 0x00 */
u32 __iomem status; /* 0x04 */
u32 __iomem ctrl; /* 0x08 */
u32 __iomem reload; /* 0x0c */
};
#define APBPS2_STATUS_DR (1<<0)
#define APBPS2_STATUS_PE (1<<1)
#define APBPS2_STATUS_FE (1<<2)
#define APBPS2_STATUS_KI (1<<3)
#define APBPS2_STATUS_RF (1<<4)
#define APBPS2_STATUS_TF (1<<5)
#define APBPS2_STATUS_TCNT (0x1f<<22)
#define APBPS2_STATUS_RCNT (0x1f<<27)
#define APBPS2_CTRL_RE (1<<0)
#define APBPS2_CTRL_TE (1<<1)
#define APBPS2_CTRL_RI (1<<2)
#define APBPS2_CTRL_TI (1<<3)
struct apbps2_priv {
struct serio *io;
struct apbps2_regs __iomem *regs;
};
static int apbps2_idx;
static irqreturn_t apbps2_isr(int irq, void *dev_id)
{
struct apbps2_priv *priv = dev_id;
unsigned long status, data, rxflags;
irqreturn_t ret = IRQ_NONE;
while ((status = ioread32be(&priv->regs->status)) & APBPS2_STATUS_DR) {
data = ioread32be(&priv->regs->data);
rxflags = (status & APBPS2_STATUS_PE) ? SERIO_PARITY : 0;
rxflags |= (status & APBPS2_STATUS_FE) ? SERIO_FRAME : 0;
/* clear error bits? */
if (rxflags)
iowrite32be(0, &priv->regs->status);
serio_interrupt(priv->io, data, rxflags);
ret = IRQ_HANDLED;
}
return ret;
}
static int apbps2_write(struct serio *io, unsigned char val)
{
struct apbps2_priv *priv = io->port_data;
unsigned int tleft = 10000; /* timeout in 100ms */
/* delay until PS/2 controller has room for more chars */
while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) && tleft--)
udelay(10);
if ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) == 0) {
iowrite32be(val, &priv->regs->data);
iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI | APBPS2_CTRL_TE,
&priv->regs->ctrl);
return 0;
}
return -ETIMEDOUT;
}
static int apbps2_open(struct serio *io)
{
struct apbps2_priv *priv = io->port_data;
int limit;
/* clear error flags */
iowrite32be(0, &priv->regs->status);
/* Clear old data if available (unlikely) */
limit = 1024;
while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit)
ioread32be(&priv->regs->data);
/* Enable reciever and it's interrupt */
iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl);
return 0;
}
static void apbps2_close(struct serio *io)
{
struct apbps2_priv *priv = io->port_data;
/* stop interrupts at PS/2 HW level */
iowrite32be(0, &priv->regs->ctrl);
}
/* Initialize one APBPS2 PS/2 core */
static int apbps2_of_probe(struct platform_device *ofdev)
{
struct apbps2_priv *priv;
int irq, err;
u32 freq_hz;
struct resource *res;
priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv) {
dev_err(&ofdev->dev, "memory allocation failed\n");
return -ENOMEM;
}
/* Find Device Address */
res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
priv->regs = devm_ioremap_resource(&ofdev->dev, res);
if (IS_ERR(priv->regs))
return PTR_ERR(priv->regs);
/* Reset hardware, disable interrupt */
iowrite32be(0, &priv->regs->ctrl);
/* IRQ */
irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
err = devm_request_irq(&ofdev->dev, irq, apbps2_isr,
IRQF_SHARED, "apbps2", priv);
if (err) {
dev_err(&ofdev->dev, "request IRQ%d failed\n", irq);
return err;
}
/* Get core frequency */
if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) {
dev_err(&ofdev->dev, "unable to get core frequency\n");
return -EINVAL;
}
/* Set reload register to core freq in kHz/10 */
iowrite32be(freq_hz / 10000, &priv->regs->reload);
priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
if (!priv->io)
return -ENOMEM;
priv->io->id.type = SERIO_8042;
priv->io->open = apbps2_open;
priv->io->close = apbps2_close;
priv->io->write = apbps2_write;
priv->io->port_data = priv;
strlcpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name));
snprintf(priv->io->phys, sizeof(priv->io->phys),
"apbps2_%d", apbps2_idx++);
dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs);
serio_register_port(priv->io);
platform_set_drvdata(ofdev, priv);
return 0;
}
static int apbps2_of_remove(struct platform_device *of_dev)
{
struct apbps2_priv *priv = platform_get_drvdata(of_dev);
serio_unregister_port(priv->io);
return 0;
}
static const struct of_device_id apbps2_of_match[] = {
{ .name = "GAISLER_APBPS2", },
{ .name = "01_060", },
{}
};
MODULE_DEVICE_TABLE(of, apbps2_of_match);
static struct platform_driver apbps2_of_driver = {
.driver = {
.name = "grlib-apbps2",
.of_match_table = apbps2_of_match,
},
.probe = apbps2_of_probe,
.remove = apbps2_of_remove,
};
module_platform_driver(apbps2_of_driver);
MODULE_AUTHOR("Aeroflex Gaisler AB.");
MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O");
MODULE_LICENSE("GPL");
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