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aha/drivers/input/serio/at32psif.c
Dmitry Torokhov e47c4f70ea Input: at32psif - do not sleep in atomic context 
We can't use msleep() while holding a spinlock, moreower serio's write()
method is supposed to be useable from inettrupt context. Let's do what
i8042 does and poll the status register every 50 us (with udelay).

Reported-by: Marjan Fojkar <marjan@pajkc.eu>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2009-12-15 00:35:08 -08:00

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/*
* Copyright (C) 2007 Atmel Corporation
*
* Driver for the AT32AP700X PS/2 controller (PSIF).
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
/* PSIF register offsets */
#define PSIF_CR 0x00
#define PSIF_RHR 0x04
#define PSIF_THR 0x08
#define PSIF_SR 0x10
#define PSIF_IER 0x14
#define PSIF_IDR 0x18
#define PSIF_IMR 0x1c
#define PSIF_PSR 0x24
/* Bitfields in control register. */
#define PSIF_CR_RXDIS_OFFSET 1
#define PSIF_CR_RXDIS_SIZE 1
#define PSIF_CR_RXEN_OFFSET 0
#define PSIF_CR_RXEN_SIZE 1
#define PSIF_CR_SWRST_OFFSET 15
#define PSIF_CR_SWRST_SIZE 1
#define PSIF_CR_TXDIS_OFFSET 9
#define PSIF_CR_TXDIS_SIZE 1
#define PSIF_CR_TXEN_OFFSET 8
#define PSIF_CR_TXEN_SIZE 1
/* Bitfields in interrupt disable, enable, mask and status register. */
#define PSIF_NACK_OFFSET 8
#define PSIF_NACK_SIZE 1
#define PSIF_OVRUN_OFFSET 5
#define PSIF_OVRUN_SIZE 1
#define PSIF_PARITY_OFFSET 9
#define PSIF_PARITY_SIZE 1
#define PSIF_RXRDY_OFFSET 4
#define PSIF_RXRDY_SIZE 1
#define PSIF_TXEMPTY_OFFSET 1
#define PSIF_TXEMPTY_SIZE 1
#define PSIF_TXRDY_OFFSET 0
#define PSIF_TXRDY_SIZE 1
/* Bitfields in prescale register. */
#define PSIF_PSR_PRSCV_OFFSET 0
#define PSIF_PSR_PRSCV_SIZE 12
/* Bitfields in receive hold register. */
#define PSIF_RHR_RXDATA_OFFSET 0
#define PSIF_RHR_RXDATA_SIZE 8
/* Bitfields in transmit hold register. */
#define PSIF_THR_TXDATA_OFFSET 0
#define PSIF_THR_TXDATA_SIZE 8
/* Bit manipulation macros */
#define PSIF_BIT(name) \
(1 << PSIF_##name##_OFFSET)
#define PSIF_BF(name, value) \
(((value) & ((1 << PSIF_##name##_SIZE) - 1)) \
<< PSIF_##name##_OFFSET)
#define PSIF_BFEXT(name, value) \
(((value) >> PSIF_##name##_OFFSET) \
& ((1 << PSIF_##name##_SIZE) - 1))
#define PSIF_BFINS(name, value, old) \
(((old) & ~(((1 << PSIF_##name##_SIZE) - 1) \
<< PSIF_##name##_OFFSET)) \
| PSIF_BF(name, value))
/* Register access macros */
#define psif_readl(port, reg) \
__raw_readl((port)->regs + PSIF_##reg)
#define psif_writel(port, reg, value) \
__raw_writel((value), (port)->regs + PSIF_##reg)
struct psif {
struct platform_device *pdev;
struct clk *pclk;
struct serio *io;
void __iomem *regs;
unsigned int irq;
unsigned int open;
/* Prevent concurrent writes to PSIF THR. */
spinlock_t lock;
};
static irqreturn_t psif_interrupt(int irq, void *_ptr)
{
struct psif *psif = _ptr;
int retval = IRQ_NONE;
unsigned int io_flags = 0;
unsigned long status;
status = psif_readl(psif, SR);
if (status & PSIF_BIT(RXRDY)) {
unsigned char val = (unsigned char) psif_readl(psif, RHR);
if (status & PSIF_BIT(PARITY))
io_flags |= SERIO_PARITY;
if (status & PSIF_BIT(OVRUN))
dev_err(&psif->pdev->dev, "overrun read error\n");
serio_interrupt(psif->io, val, io_flags);
retval = IRQ_HANDLED;
}
return retval;
}
static int psif_write(struct serio *io, unsigned char val)
{
struct psif *psif = io->port_data;
unsigned long flags;
int timeout = 10;
int retval = 0;
spin_lock_irqsave(&psif->lock, flags);
while (!(psif_readl(psif, SR) & PSIF_BIT(TXEMPTY)) && timeout--)
udelay(50);
if (timeout >= 0) {
psif_writel(psif, THR, val);
} else {
dev_dbg(&psif->pdev->dev, "timeout writing to THR\n");
retval = -EBUSY;
}
spin_unlock_irqrestore(&psif->lock, flags);
return retval;
}
static int psif_open(struct serio *io)
{
struct psif *psif = io->port_data;
int retval;
retval = clk_enable(psif->pclk);
if (retval)
goto out;
psif_writel(psif, CR, PSIF_BIT(CR_TXEN) | PSIF_BIT(CR_RXEN));
psif_writel(psif, IER, PSIF_BIT(RXRDY));
psif->open = 1;
out:
return retval;
}
static void psif_close(struct serio *io)
{
struct psif *psif = io->port_data;
psif->open = 0;
psif_writel(psif, IDR, ~0UL);
psif_writel(psif, CR, PSIF_BIT(CR_TXDIS) | PSIF_BIT(CR_RXDIS));
clk_disable(psif->pclk);
}
static void psif_set_prescaler(struct psif *psif)
{
unsigned long prscv;
unsigned long rate = clk_get_rate(psif->pclk);
/* PRSCV = Pulse length (100 us) * PSIF module frequency. */
prscv = 100 * (rate / 1000000UL);
if (prscv > ((1<<PSIF_PSR_PRSCV_SIZE) - 1)) {
prscv = (1<<PSIF_PSR_PRSCV_SIZE) - 1;
dev_dbg(&psif->pdev->dev, "pclk too fast, "
"prescaler set to max\n");
}
clk_enable(psif->pclk);
psif_writel(psif, PSR, prscv);
clk_disable(psif->pclk);
}
static int __init psif_probe(struct platform_device *pdev)
{
struct resource *regs;
struct psif *psif;
struct serio *io;
struct clk *pclk;
int irq;
int ret;
psif = kzalloc(sizeof(struct psif), GFP_KERNEL);
if (!psif) {
dev_dbg(&pdev->dev, "out of memory\n");
ret = -ENOMEM;
goto out;
}
psif->pdev = pdev;
io = kzalloc(sizeof(struct serio), GFP_KERNEL);
if (!io) {
dev_dbg(&pdev->dev, "out of memory\n");
ret = -ENOMEM;
goto out_free_psif;
}
psif->io = io;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs) {
dev_dbg(&pdev->dev, "no mmio resources defined\n");
ret = -ENOMEM;
goto out_free_io;
}
psif->regs = ioremap(regs->start, resource_size(regs));
if (!psif->regs) {
ret = -ENOMEM;
dev_dbg(&pdev->dev, "could not map I/O memory\n");
goto out_free_io;
}
pclk = clk_get(&pdev->dev, "pclk");
if (IS_ERR(pclk)) {
dev_dbg(&pdev->dev, "could not get peripheral clock\n");
ret = PTR_ERR(pclk);
goto out_iounmap;
}
psif->pclk = pclk;
/* Reset the PSIF to enter at a known state. */
ret = clk_enable(pclk);
if (ret) {
dev_dbg(&pdev->dev, "could not enable pclk\n");
goto out_put_clk;
}
psif_writel(psif, CR, PSIF_BIT(CR_SWRST));
clk_disable(pclk);
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_dbg(&pdev->dev, "could not get irq\n");
ret = -ENXIO;
goto out_put_clk;
}
ret = request_irq(irq, psif_interrupt, IRQF_SHARED, "at32psif", psif);
if (ret) {
dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
goto out_put_clk;
}
psif->irq = irq;
io->id.type = SERIO_8042;
io->write = psif_write;
io->open = psif_open;
io->close = psif_close;
snprintf(io->name, sizeof(io->name), "AVR32 PS/2 port%d", pdev->id);
snprintf(io->phys, sizeof(io->phys), "at32psif/serio%d", pdev->id);
io->port_data = psif;
io->dev.parent = &pdev->dev;
psif_set_prescaler(psif);
spin_lock_init(&psif->lock);
serio_register_port(psif->io);
platform_set_drvdata(pdev, psif);
dev_info(&pdev->dev, "Atmel AVR32 PSIF PS/2 driver on 0x%08x irq %d\n",
(int)psif->regs, psif->irq);
return 0;
out_put_clk:
clk_put(psif->pclk);
out_iounmap:
iounmap(psif->regs);
out_free_io:
kfree(io);
out_free_psif:
kfree(psif);
out:
return ret;
}
static int __exit psif_remove(struct platform_device *pdev)
{
struct psif *psif = platform_get_drvdata(pdev);
psif_writel(psif, IDR, ~0UL);
psif_writel(psif, CR, PSIF_BIT(CR_TXDIS) | PSIF_BIT(CR_RXDIS));
serio_unregister_port(psif->io);
iounmap(psif->regs);
free_irq(psif->irq, psif);
clk_put(psif->pclk);
kfree(psif);
platform_set_drvdata(pdev, NULL);
return 0;
}
#ifdef CONFIG_PM
static int psif_suspend(struct platform_device *pdev, pm_message_t state)
{
struct psif *psif = platform_get_drvdata(pdev);
if (psif->open) {
psif_writel(psif, CR, PSIF_BIT(CR_RXDIS) | PSIF_BIT(CR_TXDIS));
clk_disable(psif->pclk);
}
return 0;
}
static int psif_resume(struct platform_device *pdev)
{
struct psif *psif = platform_get_drvdata(pdev);
if (psif->open) {
clk_enable(psif->pclk);
psif_set_prescaler(psif);
psif_writel(psif, CR, PSIF_BIT(CR_RXEN) | PSIF_BIT(CR_TXEN));
}
return 0;
}
#else
#define psif_suspend NULL
#define psif_resume NULL
#endif
static struct platform_driver psif_driver = {
.remove = __exit_p(psif_remove),
.driver = {
.name = "atmel_psif",
.owner = THIS_MODULE,
},
.suspend = psif_suspend,
.resume = psif_resume,
};
static int __init psif_init(void)
{
return platform_driver_probe(&psif_driver, psif_probe);
}
static void __exit psif_exit(void)
{
platform_driver_unregister(&psif_driver);
}
module_init(psif_init);
module_exit(psif_exit);
MODULE_AUTHOR("Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>");
MODULE_DESCRIPTION("Atmel AVR32 PSIF PS/2 driver");
MODULE_LICENSE("GPL");
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