2a341f5cf5
Create <linux/atmel_tc.h> based on <asm-arm/arch-at91/at91-tc.h> and the
at91sam9263 and at32ap7000 datasheets. Most AT91 and AT32 SOCs have one
or two of these TC blocks, which include three 16-bit timers that can be
interconnected in various ways.
These TC blocks can be used for external interfacing (such as PWM and
measurement), or used as somewhat quirky sixteen-bit timers.
Changes relative to the original version:
* Drop unneeded inclusion of <linux/mutex.h>
* Support an arbitrary number of TC blocks
* Return a struct with information about a TC block from
atmel_tc_alloc() instead of using a combination of return values
and "out" parameters.
* ioremap() the I/O registers on allocation
* Look up clocks and irqs for all channels
* Add "name" parameter to atmel_tc_alloc() and use this when
requesting the iomem resource.
* Check if the platform provided the necessary resources at probe()
time instead of when the TCB is allocated.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
161 lines
3.5 KiB
C
161 lines
3.5 KiB
C
#include <linux/atmel_tc.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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/* Number of bytes to reserve for the iomem resource */
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#define ATMEL_TC_IOMEM_SIZE 256
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/*
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* This is a thin library to solve the problem of how to portably allocate
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* one of the TC blocks. For simplicity, it doesn't currently expect to
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* share individual timers between different drivers.
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*/
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#if defined(CONFIG_AVR32)
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/* AVR32 has these divide PBB */
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const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
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EXPORT_SYMBOL(atmel_tc_divisors);
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#elif defined(CONFIG_ARCH_AT91)
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/* AT91 has these divide MCK */
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const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
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EXPORT_SYMBOL(atmel_tc_divisors);
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#endif
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static DEFINE_SPINLOCK(tc_list_lock);
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static LIST_HEAD(tc_list);
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/**
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* atmel_tc_alloc - allocate a specified TC block
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* @block: which block to allocate
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* @name: name to be associated with the iomem resource
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*
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* Caller allocates a block. If it is available, a pointer to a
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* pre-initialized struct atmel_tc is returned. The caller can access
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* the registers directly through the "regs" field.
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*/
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struct atmel_tc *atmel_tc_alloc(unsigned block, const char *name)
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{
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struct atmel_tc *tc;
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struct platform_device *pdev = NULL;
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struct resource *r;
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spin_lock(&tc_list_lock);
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list_for_each_entry(tc, &tc_list, node) {
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if (tc->pdev->id == block) {
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pdev = tc->pdev;
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break;
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}
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}
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if (!pdev || tc->iomem)
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goto fail;
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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r = request_mem_region(r->start, ATMEL_TC_IOMEM_SIZE, name);
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if (!r)
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goto fail;
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tc->regs = ioremap(r->start, ATMEL_TC_IOMEM_SIZE);
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if (!tc->regs)
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goto fail_ioremap;
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tc->iomem = r;
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out:
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spin_unlock(&tc_list_lock);
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return tc;
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fail_ioremap:
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release_resource(r);
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fail:
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tc = NULL;
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goto out;
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}
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EXPORT_SYMBOL_GPL(atmel_tc_alloc);
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/**
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* atmel_tc_free - release a specified TC block
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* @tc: Timer/counter block that was returned by atmel_tc_alloc()
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*
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* This reverses the effect of atmel_tc_alloc(), unmapping the I/O
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* registers, invalidating the resource returned by that routine and
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* making the TC available to other drivers.
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*/
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void atmel_tc_free(struct atmel_tc *tc)
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{
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spin_lock(&tc_list_lock);
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if (tc->regs) {
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iounmap(tc->regs);
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release_resource(tc->iomem);
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tc->regs = NULL;
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tc->iomem = NULL;
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}
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spin_unlock(&tc_list_lock);
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}
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EXPORT_SYMBOL_GPL(atmel_tc_free);
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static int __init tc_probe(struct platform_device *pdev)
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{
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struct atmel_tc *tc;
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struct clk *clk;
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int irq;
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if (!platform_get_resource(pdev, IORESOURCE_MEM, 0))
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return -EINVAL;
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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return -EINVAL;
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tc = kzalloc(sizeof(struct atmel_tc), GFP_KERNEL);
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if (!tc)
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return -ENOMEM;
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tc->pdev = pdev;
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clk = clk_get(&pdev->dev, "t0_clk");
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if (IS_ERR(clk)) {
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kfree(tc);
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return -EINVAL;
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}
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tc->clk[0] = clk;
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tc->clk[1] = clk_get(&pdev->dev, "t1_clk");
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if (IS_ERR(tc->clk[1]))
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tc->clk[1] = clk;
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tc->clk[2] = clk_get(&pdev->dev, "t2_clk");
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if (IS_ERR(tc->clk[2]))
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tc->clk[2] = clk;
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tc->irq[0] = irq;
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tc->irq[1] = platform_get_irq(pdev, 1);
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if (tc->irq[1] < 0)
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tc->irq[1] = irq;
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tc->irq[2] = platform_get_irq(pdev, 2);
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if (tc->irq[2] < 0)
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tc->irq[2] = irq;
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spin_lock(&tc_list_lock);
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list_add_tail(&tc->node, &tc_list);
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spin_unlock(&tc_list_lock);
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return 0;
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}
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static struct platform_driver tc_driver = {
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.driver.name = "atmel_tcb",
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};
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static int __init tc_init(void)
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{
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return platform_driver_probe(&tc_driver, tc_probe);
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}
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arch_initcall(tc_init);
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