177 lines
3.5 KiB
C
177 lines
3.5 KiB
C
/*
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* Atmel SSC driver
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*
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* Copyright (C) 2007 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/platform_device.h>
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#include <linux/list.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/spinlock.h>
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#include <linux/atmel-ssc.h>
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#include <linux/slab.h>
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/* Serialize access to ssc_list and user count */
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static DEFINE_SPINLOCK(user_lock);
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static LIST_HEAD(ssc_list);
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struct ssc_device *ssc_request(unsigned int ssc_num)
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{
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int ssc_valid = 0;
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struct ssc_device *ssc;
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spin_lock(&user_lock);
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list_for_each_entry(ssc, &ssc_list, list) {
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if (ssc->pdev->id == ssc_num) {
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ssc_valid = 1;
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break;
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}
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}
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if (!ssc_valid) {
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spin_unlock(&user_lock);
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pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
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return ERR_PTR(-ENODEV);
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}
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if (ssc->user) {
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spin_unlock(&user_lock);
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dev_dbg(&ssc->pdev->dev, "module busy\n");
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return ERR_PTR(-EBUSY);
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}
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ssc->user++;
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spin_unlock(&user_lock);
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clk_enable(ssc->clk);
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return ssc;
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}
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EXPORT_SYMBOL(ssc_request);
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void ssc_free(struct ssc_device *ssc)
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{
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spin_lock(&user_lock);
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if (ssc->user) {
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ssc->user--;
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clk_disable(ssc->clk);
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} else {
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dev_dbg(&ssc->pdev->dev, "device already free\n");
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}
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spin_unlock(&user_lock);
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}
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EXPORT_SYMBOL(ssc_free);
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static int __init ssc_probe(struct platform_device *pdev)
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{
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int retval = 0;
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struct resource *regs;
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struct ssc_device *ssc;
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ssc = kzalloc(sizeof(struct ssc_device), GFP_KERNEL);
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if (!ssc) {
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dev_dbg(&pdev->dev, "out of memory\n");
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retval = -ENOMEM;
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goto out;
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}
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regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!regs) {
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dev_dbg(&pdev->dev, "no mmio resource defined\n");
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retval = -ENXIO;
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goto out_free;
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}
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ssc->clk = clk_get(&pdev->dev, "pclk");
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if (IS_ERR(ssc->clk)) {
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dev_dbg(&pdev->dev, "no pclk clock defined\n");
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retval = -ENXIO;
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goto out_free;
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}
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ssc->pdev = pdev;
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ssc->regs = ioremap(regs->start, resource_size(regs));
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if (!ssc->regs) {
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dev_dbg(&pdev->dev, "ioremap failed\n");
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retval = -EINVAL;
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goto out_clk;
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}
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/* disable all interrupts */
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clk_enable(ssc->clk);
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ssc_writel(ssc->regs, IDR, ~0UL);
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ssc_readl(ssc->regs, SR);
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clk_disable(ssc->clk);
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ssc->irq = platform_get_irq(pdev, 0);
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if (!ssc->irq) {
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dev_dbg(&pdev->dev, "could not get irq\n");
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retval = -ENXIO;
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goto out_unmap;
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}
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spin_lock(&user_lock);
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list_add_tail(&ssc->list, &ssc_list);
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spin_unlock(&user_lock);
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platform_set_drvdata(pdev, ssc);
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dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
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ssc->regs, ssc->irq);
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goto out;
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out_unmap:
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iounmap(ssc->regs);
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out_clk:
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clk_put(ssc->clk);
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out_free:
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kfree(ssc);
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out:
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return retval;
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}
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static int __devexit ssc_remove(struct platform_device *pdev)
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{
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struct ssc_device *ssc = platform_get_drvdata(pdev);
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spin_lock(&user_lock);
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iounmap(ssc->regs);
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clk_put(ssc->clk);
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list_del(&ssc->list);
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kfree(ssc);
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spin_unlock(&user_lock);
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return 0;
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}
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static struct platform_driver ssc_driver = {
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.remove = __devexit_p(ssc_remove),
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.driver = {
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.name = "ssc",
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.owner = THIS_MODULE,
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},
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};
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static int __init ssc_init(void)
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{
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return platform_driver_probe(&ssc_driver, ssc_probe);
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}
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module_init(ssc_init);
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static void __exit ssc_exit(void)
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{
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platform_driver_unregister(&ssc_driver);
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}
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module_exit(ssc_exit);
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MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
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MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:ssc");
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