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