diff options
Diffstat (limited to 'drivers/misc/atmel_tclib.c')
| -rw-r--r-- | drivers/misc/atmel_tclib.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c new file mode 100644 index 000000000..7de7840f6 --- /dev/null +++ b/drivers/misc/atmel_tclib.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/of.h> +#include <soc/at91/atmel_tcb.h> + +/* + * This is a thin library to solve the problem of how to portably allocate + * one of the TC blocks. For simplicity, it doesn't currently expect to + * share individual timers between different drivers. + */ + +#if defined(CONFIG_AVR32) +/* AVR32 has these divide PBB */ +const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, }; +EXPORT_SYMBOL(atmel_tc_divisors); + +#elif defined(CONFIG_ARCH_AT91) +/* AT91 has these divide MCK */ +const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, }; +EXPORT_SYMBOL(atmel_tc_divisors); + +#endif + +static DEFINE_SPINLOCK(tc_list_lock); +static LIST_HEAD(tc_list); + +/** + * atmel_tc_alloc - allocate a specified TC block + * @block: which block to allocate + * + * Caller allocates a block. If it is available, a pointer to a + * pre-initialized struct atmel_tc is returned. The caller can access + * the registers directly through the "regs" field. + */ +struct atmel_tc *atmel_tc_alloc(unsigned block) +{ + struct atmel_tc *tc; + struct platform_device *pdev = NULL; + + spin_lock(&tc_list_lock); + list_for_each_entry(tc, &tc_list, node) { + if (tc->allocated) + continue; + + if ((tc->pdev->dev.of_node && tc->id == block) || + (tc->pdev->id == block)) { + pdev = tc->pdev; + tc->allocated = true; + break; + } + } + spin_unlock(&tc_list_lock); + + return pdev ? tc : NULL; +} +EXPORT_SYMBOL_GPL(atmel_tc_alloc); + +/** + * atmel_tc_free - release a specified TC block + * @tc: Timer/counter block that was returned by atmel_tc_alloc() + * + * This reverses the effect of atmel_tc_alloc(), invalidating the resource + * returned by that routine and making the TC available to other drivers. + */ +void atmel_tc_free(struct atmel_tc *tc) +{ + spin_lock(&tc_list_lock); + if (tc->allocated) + tc->allocated = false; + spin_unlock(&tc_list_lock); +} +EXPORT_SYMBOL_GPL(atmel_tc_free); + +#if defined(CONFIG_OF) +static struct atmel_tcb_config tcb_rm9200_config = { + .counter_width = 16, +}; + +static struct atmel_tcb_config tcb_sam9x5_config = { + .counter_width = 32, +}; + +static const struct of_device_id atmel_tcb_dt_ids[] = { + { + .compatible = "atmel,at91rm9200-tcb", + .data = &tcb_rm9200_config, + }, { + .compatible = "atmel,at91sam9x5-tcb", + .data = &tcb_sam9x5_config, + }, { + /* sentinel */ + } +}; + +MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids); +#endif + +static int __init tc_probe(struct platform_device *pdev) +{ + struct atmel_tc *tc; + struct clk *clk; + int irq; + unsigned int i; + + if (of_get_child_count(pdev->dev.of_node)) + return -EBUSY; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return -EINVAL; + + tc = devm_kzalloc(&pdev->dev, sizeof(struct atmel_tc), GFP_KERNEL); + if (!tc) + return -ENOMEM; + + tc->pdev = pdev; + + clk = devm_clk_get(&pdev->dev, "t0_clk"); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + tc->slow_clk = devm_clk_get(&pdev->dev, "slow_clk"); + if (IS_ERR(tc->slow_clk)) + return PTR_ERR(tc->slow_clk); + + tc->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(tc->regs)) + return PTR_ERR(tc->regs); + + /* Now take SoC information if available */ + if (pdev->dev.of_node) { + const struct of_device_id *match; + match = of_match_node(atmel_tcb_dt_ids, pdev->dev.of_node); + if (match) + tc->tcb_config = match->data; + + tc->id = of_alias_get_id(tc->pdev->dev.of_node, "tcb"); + } else { + tc->id = pdev->id; + } + + tc->clk[0] = clk; + tc->clk[1] = devm_clk_get(&pdev->dev, "t1_clk"); + if (IS_ERR(tc->clk[1])) + tc->clk[1] = clk; + tc->clk[2] = devm_clk_get(&pdev->dev, "t2_clk"); + if (IS_ERR(tc->clk[2])) + tc->clk[2] = clk; + + tc->irq[0] = irq; + tc->irq[1] = platform_get_irq(pdev, 1); + if (tc->irq[1] < 0) + tc->irq[1] = irq; + tc->irq[2] = platform_get_irq(pdev, 2); + if (tc->irq[2] < 0) + tc->irq[2] = irq; + + for (i = 0; i < 3; i++) + writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR)); + + spin_lock(&tc_list_lock); + list_add_tail(&tc->node, &tc_list); + spin_unlock(&tc_list_lock); + + platform_set_drvdata(pdev, tc); + + return 0; +} + +static void tc_shutdown(struct platform_device *pdev) +{ + int i; + struct atmel_tc *tc = platform_get_drvdata(pdev); + + for (i = 0; i < 3; i++) + writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR)); +} + +static struct platform_driver tc_driver = { + .driver = { + .name = "atmel_tcb", + .of_match_table = of_match_ptr(atmel_tcb_dt_ids), + }, + .shutdown = tc_shutdown, +}; + +static int __init tc_init(void) +{ + return platform_driver_probe(&tc_driver, tc_probe); +} +arch_initcall(tc_init); |