[PATCH v4 5/8] ARM: S5PV310: Add Timer support
Kyungmin Park
kmpark at infradead.org
Tue Jul 27 00:35:25 EDT 2010
On Tue, Jul 27, 2010 at 1:12 PM, Sangbeom Kim <sbkim73 at samsung.com> wrote:
> Hi! Kyungmin,
>
> After booting, clock event is generated by 2 arm private timers.
> What do you mean by 'change the pwm2 pin to i2c functions' ?
> What do you use for I2C emulation? (TOUT2 or gpio)
> Could you explain it in detail?
In the spec, PWM2 is muxed with I2C_7. I muxed it I2C pin to use i2c chip.
Thank you,
Kyungmin Park
>
> Thanks and regards,
> Sangbeom Kim
>
> Kyungmin Park <kmpark at infradead.org> wrote:
>
>>Can you confirm that during boot time, change the pwm2 pin to i2c
>>functions and still it's working correctly?
>>
>>1. pwm2 is used for clock event at first boot.
>>2. during i2c init, pwm2 pin is changed to i2c functionality.
>>
>>then where can get the clockevent?
>>
>>Another possible scenarios is that.
>>pwm2 pin is changed to i2c function at bootloader to access the i2c chips.
>>Then below code is working?
>>
>>Thank you,
>>Kyungmin Park
>>
>>On Mon, Jul 26, 2010 at 9:42 PM, Kukjin Kim <kgene.kim at samsung.com> wrote:
>>> From: Changhwan Youn <chaos.youn at samsung.com>
>>>
>>> This patch adds timer support for S5PV310. Until now, all S5P SoCs
>>> use CONFIG_ARCH_USES_GETTIMEOFFSET macro as a default configuration.
>>> Instead,S5PV310 implements clocksource and clock_event_device to
>>> support the high resolution timer and tickless system.
>>>
>>> Signed-off-by: Changhwan Youn <chaos.youn at samsung.com>
>>> Signed-off-by: Hyuk Lee <hyuk1.lee at samsung.com>
>>> Signed-off-by: Kukjin Kim <kgene.kim at samsung.com>
>>> ---
>>> Changes since v3:
>>>
>>> - Changes clock source from PWM2 to PWM4 because PWM4 cannot be used for
>>> other purpose such as external output function through GPIO.
>>>
>>> arch/arm/mach-s5pv310/include/mach/pwm-clock.h | 70 ++++++
>>> arch/arm/mach-s5pv310/localtimer.c | 25 ++
>>> arch/arm/mach-s5pv310/time.c | 287
>>++++++++++++++++++++++++
>>> arch/arm/plat-s5p/include/plat/s5pv310.h | 1 +
>>> arch/arm/plat-samsung/Makefile | 2 +-
>>> 5 files changed, 384 insertions(+), 1 deletions(-)
>>> create mode 100644 arch/arm/mach-s5pv310/include/mach/pwm-clock.h
>>> create mode 100644 arch/arm/mach-s5pv310/localtimer.c
>>> create mode 100644 arch/arm/mach-s5pv310/time.c
>>>
>>> diff --git a/arch/arm/mach-s5pv310/include/mach/pwm-clock.h
>>b/arch/arm/mach-s5pv310/include/mach/pwm-clock.h
>>> new file mode 100644
>>> index 0000000..7e6da27
>>> --- /dev/null
>>> +++ b/arch/arm/mach-s5pv310/include/mach/pwm-clock.h
>>> @@ -0,0 +1,70 @@
>>> +/* linux/arch/arm/mach-s5pv310/include/mach/pwm-clock.h
>>> + *
>>> + * Copyright (c) 2010 Samsung Electronics Co., Ltd.
>>> + * http://www.samsung.com/
>>> + *
>>> + * Copyright 2008 Openmoko, Inc.
>>> + * Copyright 2008 Simtec Electronics
>>> + * Ben Dooks <ben at simtec.co.uk>
>>> + * http://armlinux.simtec.co.uk/
>>> + *
>>> + * Based on arch/arm/mach-s3c64xx/include/mach/pwm-clock.h
>>> + *
>>> + * S5PV310 - pwm clock and timer support
>>> + *
>>> + * 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.
>>> +*/
>>> +
>>> +#ifndef __ASM_ARCH_PWMCLK_H
>>> +#define __ASM_ARCH_PWMCLK_H __FILE__
>>> +
>>> +/**
>>> + * pwm_cfg_src_is_tclk() - return whether the given mux config is a tclk
>>> + * @tcfg: The timer TCFG1 register bits shifted down to 0.
>>> + *
>>> + * Return true if the given configuration from TCFG1 is a TCLK instead
>>> + * any of the TDIV clocks.
>>> + */
>>> +static inline int pwm_cfg_src_is_tclk(unsigned long tcfg)
>>> +{
>>> + return tcfg == S3C64XX_TCFG1_MUX_TCLK;
>>> +}
>>> +
>>> +/**
>>> + * tcfg_to_divisor() - convert tcfg1 setting to a divisor
>>> + * @tcfg1: The tcfg1 setting, shifted down.
>>> + *
>>> + * Get the divisor value for the given tcfg1 setting. We assume the
>>> + * caller has already checked to see if this is not a TCLK source.
>>> + */
>>> +static inline unsigned long tcfg_to_divisor(unsigned long tcfg1)
>>> +{
>>> + return 1 << tcfg1;
>>> +}
>>> +
>>> +/**
>>> + * pwm_tdiv_has_div1() - does the tdiv setting have a /1
>>> + *
>>> + * Return true if we have a /1 in the tdiv setting.
>>> + */
>>> +static inline unsigned int pwm_tdiv_has_div1(void)
>>> +{
>>> + return 1;
>>> +}
>>> +
>>> +/**
>>> + * pwm_tdiv_div_bits() - calculate TCFG1 divisor value.
>>> + * @div: The divisor to calculate the bit information for.
>>> + *
>>> + * Turn a divisor into the necessary bit field for TCFG1.
>>> + */
>>> +static inline unsigned long pwm_tdiv_div_bits(unsigned int div)
>>> +{
>>> + return ilog2(div);
>>> +}
>>> +
>>> +#define S3C_TCFG1_MUX_TCLK S3C64XX_TCFG1_MUX_TCLK
>>> +
>>> +#endif /* __ASM_ARCH_PWMCLK_H */
>>> diff --git a/arch/arm/mach-s5pv310/localtimer.c b/arch/arm/mach-
>>s5pv310/localtimer.c
>>> new file mode 100644
>>> index 0000000..2784036
>>> --- /dev/null
>>> +++ b/arch/arm/mach-s5pv310/localtimer.c
>>> @@ -0,0 +1,25 @@
>>> +/* linux/arch/arm/mach-s5pv310/localtimer.c
>>> + *
>>> + * Cloned from linux/arch/arm/mach-realview/localtimer.c
>>> + *
>>> + * Copyright (C) 2002 ARM Ltd.
>>> + * All Rights Reserved
>>> + *
>>> + * 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.
>>> +*/
>>> +
>>> +#include <linux/clockchips.h>
>>> +
>>> +#include <asm/irq.h>
>>> +#include <asm/localtimer.h>
>>> +
>>> +/*
>>> + * Setup the local clock events for a CPU.
>>> + */
>>> +void __cpuinit local_timer_setup(struct clock_event_device *evt)
>>> +{
>>> + evt->irq = IRQ_LOCALTIMER;
>>> + twd_timer_setup(evt);
>>> +}
>>> diff --git a/arch/arm/mach-s5pv310/time.c b/arch/arm/mach-s5pv310/time.c
>>> new file mode 100644
>>> index 0000000..01b012a
>>> --- /dev/null
>>> +++ b/arch/arm/mach-s5pv310/time.c
>>> @@ -0,0 +1,287 @@
>>> +/* linux/arch/arm/mach-s5pv310/time.c
>>> + *
>>> + * Copyright (c) 2010 Samsung Electronics Co., Ltd.
>>> + * http://www.samsung.com
>>> + *
>>> + * S5PV310 (and compatible) HRT support
>>> + * PWM 2/4 is used for this feature
>>> + *
>>> + * 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.
>>> +*/
>>> +
>>> +#include <linux/sched.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/irq.h>
>>> +#include <linux/err.h>
>>> +#include <linux/clk.h>
>>> +#include <linux/clockchips.h>
>>> +#include <linux/platform_device.h>
>>> +
>>> +#include <asm/smp_twd.h>
>>> +
>>> +#include <mach/map.h>
>>> +#include <plat/regs-timer.h>
>>> +#include <asm/mach/time.h>
>>> +
>>> +static unsigned long clock_count_per_tick;
>>> +
>>> +static struct clk *tin2;
>>> +static struct clk *tin4;
>>> +static struct clk *tdiv2;
>>> +static struct clk *tdiv4;
>>> +static struct clk *timerclk;
>>> +
>>> +static void s5pv310_pwm_stop(unsigned int pwm_id)
>>> +{
>>> + unsigned long tcon;
>>> +
>>> + tcon = __raw_readl(S3C2410_TCON);
>>> +
>>> + switch (pwm_id) {
>>> + case 2:
>>> + tcon &= ~S3C2410_TCON_T2START;
>>> + break;
>>> + case 4:
>>> + tcon &= ~S3C2410_TCON_T4START;
>>> + break;
>>> + default:
>>> + break;
>>> + }
>>> + __raw_writel(tcon, S3C2410_TCON);
>>> +}
>>> +
>>> +static void s5pv310_pwm_init(unsigned int pwm_id, unsigned long tcnt)
>>> +{
>>> + unsigned long tcon;
>>> +
>>> + tcon = __raw_readl(S3C2410_TCON);
>>> +
>>> + /* timers reload after counting zero, so reduce the count by 1 */
>>> + tcnt--;
>>> +
>>> + /* ensure timer is stopped... */
>>> + switch (pwm_id) {
>>> + case 2:
>>> + tcon &= ~(0xf<<12);
>>> + tcon |= S3C2410_TCON_T2MANUALUPD;
>>> +
>>> + __raw_writel(tcnt, S3C2410_TCNTB(2));
>>> + __raw_writel(tcnt, S3C2410_TCMPB(2));
>>> + __raw_writel(tcon, S3C2410_TCON);
>>> +
>>> + break;
>>> + case 4:
>>> + tcon &= ~(7<<20);
>>> + tcon |= S3C2410_TCON_T4MANUALUPD;
>>> +
>>> + __raw_writel(tcnt, S3C2410_TCNTB(4));
>>> + __raw_writel(tcnt, S3C2410_TCMPB(4));
>>> + __raw_writel(tcon, S3C2410_TCON);
>>> +
>>> + break;
>>> + default:
>>> + break;
>>> + }
>>> +}
>>> +
>>> +static inline void s5pv310_pwm_start(unsigned int pwm_id, bool periodic)
>>> +{
>>> + unsigned long tcon;
>>> +
>>> + tcon = __raw_readl(S3C2410_TCON);
>>> +
>>> + switch (pwm_id) {
>>> + case 2:
>>> + tcon |= S3C2410_TCON_T2START;
>>> + tcon &= ~S3C2410_TCON_T2MANUALUPD;
>>> +
>>> + if (periodic)
>>> + tcon |= S3C2410_TCON_T2RELOAD;
>>> + else
>>> + tcon &= ~S3C2410_TCON_T2RELOAD;
>>> + break;
>>> + case 4:
>>> + tcon |= S3C2410_TCON_T4START;
>>> + tcon &= ~S3C2410_TCON_T4MANUALUPD;
>>> +
>>> + if (periodic)
>>> + tcon |= S3C2410_TCON_T4RELOAD;
>>> + else
>>> + tcon &= ~S3C2410_TCON_T4RELOAD;
>>> + break;
>>> + default:
>>> + break;
>>> + }
>>> + __raw_writel(tcon, S3C2410_TCON);
>>> +}
>>> +
>>> +static int s5pv310_pwm_set_next_event(unsigned long cycles,
>>> + struct clock_event_device *evt)
>>> +{
>>> + s5pv310_pwm_init(2, cycles);
>>> + s5pv310_pwm_start(2, 0);
>>> + return 0;
>>> +}
>>> +
>>> +static void s5pv310_pwm_set_mode(enum clock_event_mode mode,
>>> + struct clock_event_device *evt)
>>> +{
>>> + s5pv310_pwm_stop(2);
>>> +
>>> + switch (mode) {
>>> + case CLOCK_EVT_MODE_PERIODIC:
>>> + s5pv310_pwm_init(2, clock_count_per_tick);
>>> + s5pv310_pwm_start(2, 1);
>>> + break;
>>> + case CLOCK_EVT_MODE_ONESHOT:
>>> + break;
>>> + case CLOCK_EVT_MODE_UNUSED:
>>> + case CLOCK_EVT_MODE_SHUTDOWN:
>>> + case CLOCK_EVT_MODE_RESUME:
>>> + break;
>>> + }
>>> +}
>>> +
>>> +static struct clock_event_device pwm_event_device = {
>>> + .name = "pwm_timer2",
>>> + .features = CLOCK_EVT_FEAT_PERIODIC |
> CLOCK_EVT_FEAT_ONESHOT,
>>> + .rating = 200,
>>> + .shift = 32,
>>> + .set_next_event = s5pv310_pwm_set_next_event,
>>> + .set_mode = s5pv310_pwm_set_mode,
>>> +};
>>> +
>>> +irqreturn_t s5pv310_clock_event_isr(int irq, void *dev_id)
>>> +{
>>> + struct clock_event_device *evt = &pwm_event_device;
>>> +
>>> + evt->event_handler(evt);
>>> +
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static struct irqaction s5pv310_clock_event_irq = {
>>> + .name = "pwm_timer2_irq",
>>> + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
>>> + .handler = s5pv310_clock_event_isr,
>>> +};
>>> +
>>> +static void __init s5pv310_clockevent_init(void)
>>> +{
>>> + unsigned long pclk;
>>> + unsigned long clock_rate;
>>> + struct clk *tscaler;
>>> +
>>> + pclk = clk_get_rate(timerclk);
>>> +
>>> + /* configure clock tick */
>>> +
>>> + tscaler = clk_get_parent(tdiv2);
>>> +
>>> + clk_set_rate(tscaler, pclk / 2);
>>> + clk_set_rate(tdiv2, pclk / 2);
>>> + clk_set_parent(tin2, tdiv2);
>>> +
>>> + clock_rate = clk_get_rate(tin2);
>>> +
>>> + clock_count_per_tick = clock_rate / HZ;
>>> +
>>> + pwm_event_device.mult =
>>> + div_sc(clock_rate, NSEC_PER_SEC, pwm_event_device.shift);
>>> + pwm_event_device.max_delta_ns =
>>> + clockevent_delta2ns(-1, &pwm_event_device);
>>> + pwm_event_device.min_delta_ns =
>>> + clockevent_delta2ns(1, &pwm_event_device);
>>> +
>>> + pwm_event_device.cpumask = cpumask_of(0);
>>> + clockevents_register_device(&pwm_event_device);
>>> +
>>> + setup_irq(IRQ_TIMER2, &s5pv310_clock_event_irq);
>>> +}
>>> +
>>> +static cycle_t s5pv310_pwm4_read(struct clocksource *cs)
>>> +{
>>> + return (cycle_t) ~__raw_readl(S3C_TIMERREG(0x40));
>>> +}
>>> +
>>> +struct clocksource pwm_clocksource = {
>>> + .name = "pwm_timer4",
>>> + .rating = 250,
>>> + .read = s5pv310_pwm4_read,
>>> + .mask = CLOCKSOURCE_MASK(32),
>>> + .shift = 20,
>>> + .flags = CLOCK_SOURCE_IS_CONTINUOUS ,
>>> +};
>>> +
>>> +static void __init s5pv310_clocksource_init(void)
>>> +{
>>> + unsigned long pclk;
>>> + unsigned long clock_rate;
>>> +
>>> + pclk = clk_get_rate(timerclk);
>>> +
>>> + clk_set_rate(tdiv4, pclk / 2);
>>> + clk_set_parent(tin4, tdiv4);
>>> +
>>> + clock_rate = clk_get_rate(tin4);
>>> +
>>> + s5pv310_pwm_init(4, ~0);
>>> + s5pv310_pwm_start(4, 1);
>>> +
>>> + pwm_clocksource.mult =
>>> + clocksource_khz2mult(clock_rate/1000,
>>pwm_clocksource.shift);
>>> +
>>> + if (clocksource_register(&pwm_clocksource))
>>> + panic("%s: can't register clocksource\n",
>>pwm_clocksource.name);
>>> +}
>>> +
>>> +static void __init s5pv310_timer_resources(void)
>>> +{
>>> + struct platform_device tmpdev;
>>> +
>>> + tmpdev.dev.bus = &platform_bus_type;
>>> +
>>> + timerclk = clk_get(NULL, "timers");
>>> + if (IS_ERR(timerclk))
>>> + panic("failed to get timers clock for system timer");
>>> +
>>> + clk_enable(timerclk);
>>> +
>>> + tmpdev.id = 2;
>>> + tin2 = clk_get(&tmpdev.dev, "pwm-tin");
>>> + if (IS_ERR(tin2))
>>> + panic("failed to get pwm-tin2 clock for system timer");
>>> +
>>> + tdiv2 = clk_get(&tmpdev.dev, "pwm-tdiv");
>>> + if (IS_ERR(tdiv2))
>>> + panic("failed to get pwm-tdiv2 clock for system timer");
>>> + clk_enable(tin2);
>>> +
>>> + tmpdev.id = 4;
>>> + tin4 = clk_get(&tmpdev.dev, "pwm-tin");
>>> + if (IS_ERR(tin4))
>>> + panic("failed to get pwm-tin4 clock for system timer");
>>> +
>>> + tdiv4 = clk_get(&tmpdev.dev, "pwm-tdiv");
>>> + if (IS_ERR(tdiv4))
>>> + panic("failed to get pwm-tdiv4 clock for system timer");
>>> +
>>> + clk_enable(tin4);
>>> +}
>>> +
>>> +static void __init s5pv310_timer_init(void)
>>> +{
>>> +#ifdef CONFIG_LOCAL_TIMERS
>>> + twd_base = S5P_VA_TWD;
>>> +#endif
>>> +
>>> + s5pv310_timer_resources();
>>> + s5pv310_clockevent_init();
>>> + s5pv310_clocksource_init();
>>> +}
>>> +
>>> +struct sys_timer s5pv310_timer = {
>>> + .init = s5pv310_timer_init,
>>> +};
>>> diff --git a/arch/arm/plat-s5p/include/plat/s5pv310.h b/arch/arm/plat-
>>s5p/include/plat/s5pv310.h
>>> index d2f05e1..769c991 100644
>>> --- a/arch/arm/plat-s5p/include/plat/s5pv310.h
>>> +++ b/arch/arm/plat-s5p/include/plat/s5pv310.h
>>> @@ -22,6 +22,7 @@ extern int s5pv310_init(void);
>>> extern void s5pv310_init_irq(void);
>>> extern void s5pv310_map_io(void);
>>> extern void s5pv310_init_clocks(int xtal);
>>> +extern struct sys_timer s5pv310_timer;
>>>
>>> #define s5pv310_init_uarts s5pv310_common_init_uarts
>>>
>>> diff --git a/arch/arm/plat-samsung/Makefile b/arch/arm/plat-
>>samsung/Makefile
>>> index b1d82cc..0d5bf8a 100644
>>> --- a/arch/arm/plat-samsung/Makefile
>>> +++ b/arch/arm/plat-samsung/Makefile
>>> @@ -12,7 +12,7 @@ obj- :=
>>> # Objects we always build independent of SoC choice
>>>
>>> obj-y += init.o
>>> -obj-y += time.o
>>> +obj-$(CONFIG_ARCH_USES_GETTIMEOFFSET) += time.o
>>> obj-y += clock.o
>>> obj-y += pwm-clock.o
>>> obj-y += gpio.o
>>> --
>>> 1.6.2.5
>>>
>>> --
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>>
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>
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