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![Boris Brezillon](/assets/img/avatar_default.png)
Commit dca1a4b5ff
("clk: at91: keep slow clk enabled to prevent system
hang") added a workaround for the slow clock as it is not properly handled
by its users.
Get and use the slow clock as it is necessary for the timer counters.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
198 lines
4.5 KiB
C
198 lines
4.5 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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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/of.h>
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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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*
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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)
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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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spin_lock(&tc_list_lock);
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list_for_each_entry(tc, &tc_list, node) {
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if (tc->allocated)
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continue;
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if ((tc->pdev->dev.of_node && tc->id == block) ||
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(tc->pdev->id == block)) {
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pdev = tc->pdev;
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tc->allocated = true;
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break;
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}
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}
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spin_unlock(&tc_list_lock);
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return pdev ? tc : NULL;
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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(), invalidating the resource
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* returned by that routine and 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->allocated)
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tc->allocated = false;
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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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#if defined(CONFIG_OF)
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static struct atmel_tcb_config tcb_rm9200_config = {
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.counter_width = 16,
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};
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static struct atmel_tcb_config tcb_sam9x5_config = {
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.counter_width = 32,
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};
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static const struct of_device_id atmel_tcb_dt_ids[] = {
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{
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.compatible = "atmel,at91rm9200-tcb",
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.data = &tcb_rm9200_config,
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}, {
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.compatible = "atmel,at91sam9x5-tcb",
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.data = &tcb_sam9x5_config,
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}, {
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/* sentinel */
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}
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};
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MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
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#endif
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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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struct resource *r;
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unsigned int i;
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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 = devm_kzalloc(&pdev->dev, 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 = devm_clk_get(&pdev->dev, "t0_clk");
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if (IS_ERR(clk))
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return PTR_ERR(clk);
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tc->slow_clk = devm_clk_get(&pdev->dev, "slow_clk");
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if (IS_ERR(tc->slow_clk))
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return PTR_ERR(tc->slow_clk);
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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tc->regs = devm_ioremap_resource(&pdev->dev, r);
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if (IS_ERR(tc->regs))
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return PTR_ERR(tc->regs);
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/* Now take SoC information if available */
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if (pdev->dev.of_node) {
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const struct of_device_id *match;
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match = of_match_node(atmel_tcb_dt_ids, pdev->dev.of_node);
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if (match)
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tc->tcb_config = match->data;
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tc->id = of_alias_get_id(tc->pdev->dev.of_node, "tcb");
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} else {
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tc->id = pdev->id;
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}
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tc->clk[0] = clk;
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tc->clk[1] = devm_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] = devm_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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for (i = 0; i < 3; i++)
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writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
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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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platform_set_drvdata(pdev, tc);
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return 0;
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}
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static void tc_shutdown(struct platform_device *pdev)
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{
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int i;
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struct atmel_tc *tc = platform_get_drvdata(pdev);
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for (i = 0; i < 3; i++)
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writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
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}
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static struct platform_driver tc_driver = {
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.driver = {
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.name = "atmel_tcb",
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.of_match_table = of_match_ptr(atmel_tcb_dt_ids),
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},
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.shutdown = tc_shutdown,
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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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