273 lines
7.0 KiB
C
273 lines
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* OLPC serio driver for multiplexed input from Marvell MMP security processor
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*
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* Copyright (C) 2011-2013 One Laptop Per Child
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*/
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/serio.h>
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#include <linux/err.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <linux/delay.h>
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/*
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* The OLPC XO-1.75 and XO-4 laptops do not have a hardware PS/2 controller.
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* Instead, the OLPC firmware runs a bit-banging PS/2 implementation on an
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* otherwise-unused slow processor which is included in the Marvell MMP2/MMP3
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* SoC, known as the "Security Processor" (SP) or "Wireless Trusted Module"
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* (WTM). This firmware then reports its results via the WTM registers,
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* which we read from the Application Processor (AP, i.e. main CPU) in this
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* driver.
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*
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* On the hardware side we have a PS/2 mouse and an AT keyboard, the data
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* is multiplexed through this system. We create a serio port for each one,
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* and demultiplex the data accordingly.
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*/
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/* WTM register offsets */
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#define SECURE_PROCESSOR_COMMAND 0x40
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#define COMMAND_RETURN_STATUS 0x80
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#define COMMAND_FIFO_STATUS 0xc4
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#define PJ_RST_INTERRUPT 0xc8
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#define PJ_INTERRUPT_MASK 0xcc
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/*
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* The upper byte of SECURE_PROCESSOR_COMMAND and COMMAND_RETURN_STATUS is
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* used to identify which port (device) is being talked to. The lower byte
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* is the data being sent/received.
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*/
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#define PORT_MASK 0xff00
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#define DATA_MASK 0x00ff
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#define PORT_SHIFT 8
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#define KEYBOARD_PORT 0
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#define TOUCHPAD_PORT 1
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/* COMMAND_FIFO_STATUS */
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#define CMD_CNTR_MASK 0x7 /* Number of pending/unprocessed commands */
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#define MAX_PENDING_CMDS 4 /* from device specs */
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/* PJ_RST_INTERRUPT */
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#define SP_COMMAND_COMPLETE_RESET 0x1
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/* PJ_INTERRUPT_MASK */
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#define INT_0 (1 << 0)
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/* COMMAND_FIFO_STATUS */
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#define CMD_STS_MASK 0x100
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struct olpc_apsp {
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struct device *dev;
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struct serio *kbio;
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struct serio *padio;
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void __iomem *base;
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int open_count;
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int irq;
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};
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static int olpc_apsp_write(struct serio *port, unsigned char val)
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{
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struct olpc_apsp *priv = port->port_data;
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unsigned int i;
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u32 which = 0;
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if (port == priv->padio)
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which = TOUCHPAD_PORT << PORT_SHIFT;
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else
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which = KEYBOARD_PORT << PORT_SHIFT;
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dev_dbg(priv->dev, "olpc_apsp_write which=%x val=%x\n", which, val);
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for (i = 0; i < 50; i++) {
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u32 sts = readl(priv->base + COMMAND_FIFO_STATUS);
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if ((sts & CMD_CNTR_MASK) < MAX_PENDING_CMDS) {
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writel(which | val,
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priv->base + SECURE_PROCESSOR_COMMAND);
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return 0;
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}
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/* SP busy. This has not been seen in practice. */
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mdelay(1);
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}
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dev_dbg(priv->dev, "olpc_apsp_write timeout, status=%x\n",
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readl(priv->base + COMMAND_FIFO_STATUS));
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return -ETIMEDOUT;
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}
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static irqreturn_t olpc_apsp_rx(int irq, void *dev_id)
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{
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struct olpc_apsp *priv = dev_id;
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unsigned int w, tmp;
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struct serio *serio;
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/*
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* Write 1 to PJ_RST_INTERRUPT to acknowledge and clear the interrupt
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* Write 0xff00 to SECURE_PROCESSOR_COMMAND.
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*/
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tmp = readl(priv->base + PJ_RST_INTERRUPT);
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if (!(tmp & SP_COMMAND_COMPLETE_RESET)) {
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dev_warn(priv->dev, "spurious interrupt?\n");
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return IRQ_NONE;
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}
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w = readl(priv->base + COMMAND_RETURN_STATUS);
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dev_dbg(priv->dev, "olpc_apsp_rx %x\n", w);
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if (w >> PORT_SHIFT == KEYBOARD_PORT)
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serio = priv->kbio;
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else
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serio = priv->padio;
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serio_interrupt(serio, w & DATA_MASK, 0);
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/* Ack and clear interrupt */
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writel(tmp | SP_COMMAND_COMPLETE_RESET, priv->base + PJ_RST_INTERRUPT);
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writel(PORT_MASK, priv->base + SECURE_PROCESSOR_COMMAND);
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pm_wakeup_event(priv->dev, 1000);
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return IRQ_HANDLED;
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}
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static int olpc_apsp_open(struct serio *port)
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{
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struct olpc_apsp *priv = port->port_data;
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unsigned int tmp;
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unsigned long l;
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if (priv->open_count++ == 0) {
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l = readl(priv->base + COMMAND_FIFO_STATUS);
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if (!(l & CMD_STS_MASK)) {
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dev_err(priv->dev, "SP cannot accept commands.\n");
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return -EIO;
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}
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/* Enable interrupt 0 by clearing its bit */
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tmp = readl(priv->base + PJ_INTERRUPT_MASK);
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writel(tmp & ~INT_0, priv->base + PJ_INTERRUPT_MASK);
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}
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return 0;
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}
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static void olpc_apsp_close(struct serio *port)
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{
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struct olpc_apsp *priv = port->port_data;
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unsigned int tmp;
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if (--priv->open_count == 0) {
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/* Disable interrupt 0 */
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tmp = readl(priv->base + PJ_INTERRUPT_MASK);
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writel(tmp | INT_0, priv->base + PJ_INTERRUPT_MASK);
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}
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}
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static int olpc_apsp_probe(struct platform_device *pdev)
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{
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struct serio *kb_serio, *pad_serio;
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struct olpc_apsp *priv;
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struct resource *res;
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int error;
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priv = devm_kzalloc(&pdev->dev, sizeof(struct olpc_apsp), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->dev = &pdev->dev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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priv->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(priv->base)) {
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dev_err(&pdev->dev, "Failed to map WTM registers\n");
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return PTR_ERR(priv->base);
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}
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priv->irq = platform_get_irq(pdev, 0);
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if (priv->irq < 0)
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return priv->irq;
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/* KEYBOARD */
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kb_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
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if (!kb_serio)
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return -ENOMEM;
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kb_serio->id.type = SERIO_8042_XL;
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kb_serio->write = olpc_apsp_write;
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kb_serio->open = olpc_apsp_open;
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kb_serio->close = olpc_apsp_close;
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kb_serio->port_data = priv;
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kb_serio->dev.parent = &pdev->dev;
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strlcpy(kb_serio->name, "sp keyboard", sizeof(kb_serio->name));
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strlcpy(kb_serio->phys, "sp/serio0", sizeof(kb_serio->phys));
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priv->kbio = kb_serio;
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serio_register_port(kb_serio);
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/* TOUCHPAD */
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pad_serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
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if (!pad_serio) {
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error = -ENOMEM;
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goto err_pad;
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}
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pad_serio->id.type = SERIO_8042;
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pad_serio->write = olpc_apsp_write;
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pad_serio->open = olpc_apsp_open;
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pad_serio->close = olpc_apsp_close;
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pad_serio->port_data = priv;
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pad_serio->dev.parent = &pdev->dev;
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strlcpy(pad_serio->name, "sp touchpad", sizeof(pad_serio->name));
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strlcpy(pad_serio->phys, "sp/serio1", sizeof(pad_serio->phys));
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priv->padio = pad_serio;
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serio_register_port(pad_serio);
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error = request_irq(priv->irq, olpc_apsp_rx, 0, "olpc-apsp", priv);
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if (error) {
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dev_err(&pdev->dev, "Failed to request IRQ\n");
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goto err_irq;
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}
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device_init_wakeup(priv->dev, 1);
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platform_set_drvdata(pdev, priv);
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dev_dbg(&pdev->dev, "probed successfully.\n");
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return 0;
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err_irq:
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serio_unregister_port(pad_serio);
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err_pad:
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serio_unregister_port(kb_serio);
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return error;
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}
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static int olpc_apsp_remove(struct platform_device *pdev)
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{
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struct olpc_apsp *priv = platform_get_drvdata(pdev);
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free_irq(priv->irq, priv);
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serio_unregister_port(priv->kbio);
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serio_unregister_port(priv->padio);
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return 0;
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}
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static const struct of_device_id olpc_apsp_dt_ids[] = {
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{ .compatible = "olpc,ap-sp", },
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{}
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};
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MODULE_DEVICE_TABLE(of, olpc_apsp_dt_ids);
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static struct platform_driver olpc_apsp_driver = {
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.probe = olpc_apsp_probe,
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.remove = olpc_apsp_remove,
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.driver = {
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.name = "olpc-apsp",
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.of_match_table = olpc_apsp_dt_ids,
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},
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};
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MODULE_DESCRIPTION("OLPC AP-SP serio driver");
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MODULE_LICENSE("GPL");
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module_platform_driver(olpc_apsp_driver);
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