diff options
Diffstat (limited to 'kernel/drivers/clocksource/time-lpc32xx.c')
| -rw-r--r-- | kernel/drivers/clocksource/time-lpc32xx.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/kernel/drivers/clocksource/time-lpc32xx.c b/kernel/drivers/clocksource/time-lpc32xx.c new file mode 100644 index 000000000..a1c06a2bc --- /dev/null +++ b/kernel/drivers/clocksource/time-lpc32xx.c @@ -0,0 +1,272 @@ +/* + * Clocksource driver for NXP LPC32xx/18xx/43xx timer + * + * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> + * + * Based on: + * time-efm32 Copyright (C) 2013 Pengutronix + * mach-lpc32xx/timer.c Copyright (C) 2009 - 2010 NXP Semiconductors + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + */ + +#define pr_fmt(fmt) "%s: " fmt, __func__ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/sched_clock.h> + +#define LPC32XX_TIMER_IR 0x000 +#define LPC32XX_TIMER_IR_MR0INT BIT(0) +#define LPC32XX_TIMER_TCR 0x004 +#define LPC32XX_TIMER_TCR_CEN BIT(0) +#define LPC32XX_TIMER_TCR_CRST BIT(1) +#define LPC32XX_TIMER_TC 0x008 +#define LPC32XX_TIMER_PR 0x00c +#define LPC32XX_TIMER_MCR 0x014 +#define LPC32XX_TIMER_MCR_MR0I BIT(0) +#define LPC32XX_TIMER_MCR_MR0R BIT(1) +#define LPC32XX_TIMER_MCR_MR0S BIT(2) +#define LPC32XX_TIMER_MR0 0x018 +#define LPC32XX_TIMER_CTCR 0x070 + +struct lpc32xx_clock_event_ddata { + struct clock_event_device evtdev; + void __iomem *base; +}; + +/* Needed for the sched clock */ +static void __iomem *clocksource_timer_counter; + +static u64 notrace lpc32xx_read_sched_clock(void) +{ + return readl(clocksource_timer_counter); +} + +static int lpc32xx_clkevt_next_event(unsigned long delta, + struct clock_event_device *evtdev) +{ + struct lpc32xx_clock_event_ddata *ddata = + container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev); + + /* + * Place timer in reset and program the delta in the prescale + * register (PR). When the prescale counter matches the value + * in PR the counter register is incremented and the compare + * match will trigger. After setup the timer is released from + * reset and enabled. + */ + writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR); + writel_relaxed(delta, ddata->base + LPC32XX_TIMER_PR); + writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR); + + return 0; +} + +static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev) +{ + struct lpc32xx_clock_event_ddata *ddata = + container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev); + + /* Disable the timer */ + writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR); + + return 0; +} + +static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev) +{ + /* + * When using oneshot, we must also disable the timer + * to wait for the first call to set_next_event(). + */ + return lpc32xx_clkevt_shutdown(evtdev); +} + +static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id) +{ + struct lpc32xx_clock_event_ddata *ddata = dev_id; + + /* Clear match on channel 0 */ + writel_relaxed(LPC32XX_TIMER_IR_MR0INT, ddata->base + LPC32XX_TIMER_IR); + + ddata->evtdev.event_handler(&ddata->evtdev); + + return IRQ_HANDLED; +} + +static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = { + .evtdev = { + .name = "lpc3220 clockevent", + .features = CLOCK_EVT_FEAT_ONESHOT, + .rating = 300, + .set_next_event = lpc32xx_clkevt_next_event, + .set_state_shutdown = lpc32xx_clkevt_shutdown, + .set_state_oneshot = lpc32xx_clkevt_oneshot, + }, +}; + +static int __init lpc32xx_clocksource_init(struct device_node *np) +{ + void __iomem *base; + unsigned long rate; + struct clk *clk; + int ret; + + clk = of_clk_get_by_name(np, "timerclk"); + if (IS_ERR(clk)) { + pr_err("clock get failed (%lu)\n", PTR_ERR(clk)); + return PTR_ERR(clk); + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("clock enable failed (%d)\n", ret); + goto err_clk_enable; + } + + base = of_iomap(np, 0); + if (!base) { + pr_err("unable to map registers\n"); + ret = -EADDRNOTAVAIL; + goto err_iomap; + } + + /* + * Disable and reset timer then set it to free running timer + * mode (CTCR) with no prescaler (PR) or match operations (MCR). + * After setup the timer is released from reset and enabled. + */ + writel_relaxed(LPC32XX_TIMER_TCR_CRST, base + LPC32XX_TIMER_TCR); + writel_relaxed(0, base + LPC32XX_TIMER_PR); + writel_relaxed(0, base + LPC32XX_TIMER_MCR); + writel_relaxed(0, base + LPC32XX_TIMER_CTCR); + writel_relaxed(LPC32XX_TIMER_TCR_CEN, base + LPC32XX_TIMER_TCR); + + rate = clk_get_rate(clk); + ret = clocksource_mmio_init(base + LPC32XX_TIMER_TC, "lpc3220 timer", + rate, 300, 32, clocksource_mmio_readl_up); + if (ret) { + pr_err("failed to init clocksource (%d)\n", ret); + goto err_clocksource_init; + } + + clocksource_timer_counter = base + LPC32XX_TIMER_TC; + sched_clock_register(lpc32xx_read_sched_clock, 32, rate); + + return 0; + +err_clocksource_init: + iounmap(base); +err_iomap: + clk_disable_unprepare(clk); +err_clk_enable: + clk_put(clk); + return ret; +} + +static int __init lpc32xx_clockevent_init(struct device_node *np) +{ + void __iomem *base; + unsigned long rate; + struct clk *clk; + int ret, irq; + + clk = of_clk_get_by_name(np, "timerclk"); + if (IS_ERR(clk)) { + pr_err("clock get failed (%lu)\n", PTR_ERR(clk)); + return PTR_ERR(clk); + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("clock enable failed (%d)\n", ret); + goto err_clk_enable; + } + + base = of_iomap(np, 0); + if (!base) { + pr_err("unable to map registers\n"); + ret = -EADDRNOTAVAIL; + goto err_iomap; + } + + irq = irq_of_parse_and_map(np, 0); + if (!irq) { + pr_err("get irq failed\n"); + ret = -ENOENT; + goto err_irq; + } + + /* + * Disable timer and clear any pending interrupt (IR) on match + * channel 0 (MR0). Configure a compare match value of 1 on MR0 + * and enable interrupt, reset on match and stop on match (MCR). + */ + writel_relaxed(0, base + LPC32XX_TIMER_TCR); + writel_relaxed(0, base + LPC32XX_TIMER_CTCR); + writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR); + writel_relaxed(1, base + LPC32XX_TIMER_MR0); + writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R | + LPC32XX_TIMER_MCR_MR0S, base + LPC32XX_TIMER_MCR); + + rate = clk_get_rate(clk); + lpc32xx_clk_event_ddata.base = base; + clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev, + rate, 1, -1); + + ret = request_irq(irq, lpc32xx_clock_event_handler, + IRQF_TIMER | IRQF_IRQPOLL, "lpc3220 clockevent", + &lpc32xx_clk_event_ddata); + if (ret) { + pr_err("request irq failed\n"); + goto err_irq; + } + + return 0; + +err_irq: + iounmap(base); +err_iomap: + clk_disable_unprepare(clk); +err_clk_enable: + clk_put(clk); + return ret; +} + +/* + * This function asserts that we have exactly one clocksource and one + * clock_event_device in the end. + */ +static void __init lpc32xx_timer_init(struct device_node *np) +{ + static int has_clocksource, has_clockevent; + int ret; + + if (!has_clocksource) { + ret = lpc32xx_clocksource_init(np); + if (!ret) { + has_clocksource = 1; + return; + } + } + + if (!has_clockevent) { + ret = lpc32xx_clockevent_init(np); + if (!ret) { + has_clockevent = 1; + return; + } + } +} +CLOCKSOURCE_OF_DECLARE(lpc32xx_timer, "nxp,lpc3220-timer", lpc32xx_timer_init); |