diff options
author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2013-10-03 19:56:29 (GMT) |
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committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2013-10-22 20:36:33 (GMT) |
commit | 9c9b781804e0a278e258f81dfc31c50f80867730 (patch) | |
tree | ed03e43c78b0a08262c0fbab84d0891bfbee908c /drivers | |
parent | fdfcab17a26ab2179c9d233f8a1b63e93cff9a4a (diff) | |
download | linux-9c9b781804e0a278e258f81dfc31c50f80867730.tar.xz |
clocksource: Provide timekeeping for efm32 SoCs
An efm32 features 4 16-bit timers with a 10-bit prescaler. This driver
provides clocksource and clock event device using one timer instance
each.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/clocksource/Kconfig | 8 | ||||
-rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
-rw-r--r-- | drivers/clocksource/time-efm32.c | 275 |
3 files changed, 284 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 5e940f8..915a388 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -71,6 +71,14 @@ config CLKSRC_DBX500_PRCMU_SCHED_CLOCK help Use the always on PRCMU Timer as sched_clock +config CLKSRC_EFM32 + bool "Clocksource for Energy Micro's EFM32 SoCs" if !ARCH_EFM32 + depends on OF && ARM && (ARCH_EFM32 || COMPILE_TEST) + default ARCH_EFM32 + help + Support to use the timers of EFM32 SoCs as clock source and clock + event device. + config ARM_ARCH_TIMER bool select CLKSRC_OF if OF diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 704d6d3..33621ef 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_VT8500_TIMER) += vt8500_timer.o obj-$(CONFIG_ARCH_NSPIRE) += zevio-timer.o obj-$(CONFIG_ARCH_BCM) += bcm_kona_timer.o obj-$(CONFIG_CADENCE_TTC_TIMER) += cadence_ttc_timer.o +obj-$(CONFIG_CLKSRC_EFM32) += time-efm32.o obj-$(CONFIG_CLKSRC_EXYNOS_MCT) += exynos_mct.o obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o diff --git a/drivers/clocksource/time-efm32.c b/drivers/clocksource/time-efm32.c new file mode 100644 index 0000000..1a6205b --- /dev/null +++ b/drivers/clocksource/time-efm32.c @@ -0,0 +1,275 @@ +/* + * Copyright (C) 2013 Pengutronix + * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> + * + * 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/irq.h> +#include <linux/interrupt.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/clk.h> + +#define TIMERn_CTRL 0x00 +#define TIMERn_CTRL_PRESC(val) (((val) & 0xf) << 24) +#define TIMERn_CTRL_PRESC_1024 TIMERn_CTRL_PRESC(10) +#define TIMERn_CTRL_CLKSEL(val) (((val) & 0x3) << 16) +#define TIMERn_CTRL_CLKSEL_PRESCHFPERCLK TIMERn_CTRL_CLKSEL(0) +#define TIMERn_CTRL_OSMEN 0x00000010 +#define TIMERn_CTRL_MODE(val) (((val) & 0x3) << 0) +#define TIMERn_CTRL_MODE_UP TIMERn_CTRL_MODE(0) +#define TIMERn_CTRL_MODE_DOWN TIMERn_CTRL_MODE(1) + +#define TIMERn_CMD 0x04 +#define TIMERn_CMD_START 0x00000001 +#define TIMERn_CMD_STOP 0x00000002 + +#define TIMERn_IEN 0x0c +#define TIMERn_IF 0x10 +#define TIMERn_IFS 0x14 +#define TIMERn_IFC 0x18 +#define TIMERn_IRQ_UF 0x00000002 + +#define TIMERn_TOP 0x1c +#define TIMERn_CNT 0x24 + +struct efm32_clock_event_ddata { + struct clock_event_device evtdev; + void __iomem *base; + unsigned periodic_top; +}; + +static void efm32_clock_event_set_mode(enum clock_event_mode mode, + struct clock_event_device *evtdev) +{ + struct efm32_clock_event_ddata *ddata = + container_of(evtdev, struct efm32_clock_event_ddata, evtdev); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD); + writel_relaxed(ddata->periodic_top, ddata->base + TIMERn_TOP); + writel_relaxed(TIMERn_CTRL_PRESC_1024 | + TIMERn_CTRL_CLKSEL_PRESCHFPERCLK | + TIMERn_CTRL_MODE_DOWN, + ddata->base + TIMERn_CTRL); + writel_relaxed(TIMERn_CMD_START, ddata->base + TIMERn_CMD); + break; + + case CLOCK_EVT_MODE_ONESHOT: + writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD); + writel_relaxed(TIMERn_CTRL_PRESC_1024 | + TIMERn_CTRL_CLKSEL_PRESCHFPERCLK | + TIMERn_CTRL_OSMEN | + TIMERn_CTRL_MODE_DOWN, + ddata->base + TIMERn_CTRL); + break; + + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD); + break; + + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static int efm32_clock_event_set_next_event(unsigned long evt, + struct clock_event_device *evtdev) +{ + struct efm32_clock_event_ddata *ddata = + container_of(evtdev, struct efm32_clock_event_ddata, evtdev); + + writel_relaxed(TIMERn_CMD_STOP, ddata->base + TIMERn_CMD); + writel_relaxed(evt, ddata->base + TIMERn_CNT); + writel_relaxed(TIMERn_CMD_START, ddata->base + TIMERn_CMD); + + return 0; +} + +static irqreturn_t efm32_clock_event_handler(int irq, void *dev_id) +{ + struct efm32_clock_event_ddata *ddata = dev_id; + + writel_relaxed(TIMERn_IRQ_UF, ddata->base + TIMERn_IFC); + + ddata->evtdev.event_handler(&ddata->evtdev); + + return IRQ_HANDLED; +} + +static struct efm32_clock_event_ddata clock_event_ddata = { + .evtdev = { + .name = "efm32 clockevent", + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_MODE_PERIODIC, + .set_mode = efm32_clock_event_set_mode, + .set_next_event = efm32_clock_event_set_next_event, + .rating = 200, + }, +}; + +static struct irqaction efm32_clock_event_irq = { + .name = "efm32 clockevent", + .flags = IRQF_TIMER, + .handler = efm32_clock_event_handler, + .dev_id = &clock_event_ddata, +}; + +static int __init efm32_clocksource_init(struct device_node *np) +{ + struct clk *clk; + void __iomem *base; + unsigned long rate; + int ret; + + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + pr_err("failed to get clock for clocksource (%d)\n", ret); + goto err_clk_get; + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("failed to enable timer clock for clocksource (%d)\n", + ret); + goto err_clk_enable; + } + rate = clk_get_rate(clk); + + base = of_iomap(np, 0); + if (!base) { + ret = -EADDRNOTAVAIL; + pr_err("failed to map registers for clocksource\n"); + goto err_iomap; + } + + writel_relaxed(TIMERn_CTRL_PRESC_1024 | + TIMERn_CTRL_CLKSEL_PRESCHFPERCLK | + TIMERn_CTRL_MODE_UP, base + TIMERn_CTRL); + writel_relaxed(TIMERn_CMD_START, base + TIMERn_CMD); + + ret = clocksource_mmio_init(base + TIMERn_CNT, "efm32 timer", + DIV_ROUND_CLOSEST(rate, 1024), 200, 16, + clocksource_mmio_readl_up); + if (ret) { + pr_err("failed to init clocksource (%d)\n", ret); + goto err_clocksource_init; + } + + return 0; + +err_clocksource_init: + + iounmap(base); +err_iomap: + + clk_disable_unprepare(clk); +err_clk_enable: + + clk_put(clk); +err_clk_get: + + return ret; +} + +static int __init efm32_clockevent_init(struct device_node *np) +{ + struct clk *clk; + void __iomem *base; + unsigned long rate; + int irq; + int ret; + + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + pr_err("failed to get clock for clockevent (%d)\n", ret); + goto err_clk_get; + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("failed to enable timer clock for clockevent (%d)\n", + ret); + goto err_clk_enable; + } + rate = clk_get_rate(clk); + + base = of_iomap(np, 0); + if (!base) { + ret = -EADDRNOTAVAIL; + pr_err("failed to map registers for clockevent\n"); + goto err_iomap; + } + + irq = irq_of_parse_and_map(np, 0); + if (!irq) { + ret = -ENOENT; + pr_err("failed to get irq for clockevent\n"); + goto err_get_irq; + } + + writel_relaxed(TIMERn_IRQ_UF, base + TIMERn_IEN); + + clock_event_ddata.base = base; + clock_event_ddata.periodic_top = DIV_ROUND_CLOSEST(rate, 1024 * HZ); + + setup_irq(irq, &efm32_clock_event_irq); + + clockevents_config_and_register(&clock_event_ddata.evtdev, + DIV_ROUND_CLOSEST(rate, 1024), + 0xf, 0xffff); + + return 0; + +err_get_irq: + + iounmap(base); +err_iomap: + + clk_disable_unprepare(clk); +err_clk_enable: + + clk_put(clk); +err_clk_get: + + return ret; +} + +/* + * This function asserts that we have exactly one clocksource and one + * clock_event_device in the end. + */ +static void __init efm32_timer_init(struct device_node *np) +{ + static int has_clocksource, has_clockevent; + int ret; + + if (!has_clocksource) { + ret = efm32_clocksource_init(np); + if (!ret) { + has_clocksource = 1; + return; + } + } + + if (!has_clockevent) { + ret = efm32_clockevent_init(np); + if (!ret) { + has_clockevent = 1; + return; + } + } +} +CLOCKSOURCE_OF_DECLARE(efm32, "efm32,timer", efm32_timer_init); 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