| From 0e0354a566fd8c79628ed603cf9fc909461c9b84 Mon Sep 17 00:00:00 2001 |
| From: Nicolai Stange <nicstange@gmail.com> |
| Date: Mon, 6 Feb 2017 22:12:02 +0100 |
| Subject: [PATCH 002/286] clocksource: em_sti: Compute rate before registration |
| |
| With the upcoming NTP correction related rate adjustments to be implemented |
| in the clockevents core, the latter needs to get informed about every rate |
| change of a clockevent device made after its registration. |
| |
| Currently, em_sti violates this requirement in that it registers its |
| clockevent device with a dummy rate and sets its final rate through |
| clockevents_config() called from its ->set_state_oneshot(). |
| |
| This patch moves the setting of the clockevent device's rate to its |
| registration. |
| |
| I checked all current em_sti users in arch/arm/mach-shmobile and right now, |
| none of them changes any rate in any clock tree relevant to em_sti after |
| their respective time_init(). Since all em_sti instances are created after |
| time_init(), none of them should ever observe any clock rate changes. |
| |
| - Determine the ->rate value in em_sti_probe() at device probing rather |
| than at first usage. |
| - Set the clockevent device's rate at its registration. |
| - Although not strictly necessary for the upcoming clockevent core changes, |
| set the clocksource's rate at its registration for consistency. |
| |
| Signed-off-by: Nicolai Stange <nicstange@gmail.com> |
| Signed-off-by: John Stultz <john.stultz@linaro.org> |
| (cherry picked from commit 4e53aa2fde4124878fc6b2183d6e8ec46e12ceb0) |
| Signed-off-by: Simon Horman <horms+renesas@verge.net.au> |
| --- |
| drivers/clocksource/em_sti.c | 25 ++++++++++++------------- |
| 1 file changed, 12 insertions(+), 13 deletions(-) |
| |
| --- a/drivers/clocksource/em_sti.c |
| +++ b/drivers/clocksource/em_sti.c |
| @@ -84,9 +84,6 @@ static int em_sti_enable(struct em_sti_p |
| return ret; |
| } |
| |
| - /* configure channel, periodic mode and maximum timeout */ |
| - p->rate = clk_get_rate(p->clk); |
| - |
| /* reset the counter */ |
| em_sti_write(p, STI_SET_H, 0x40000000); |
| em_sti_write(p, STI_SET_L, 0x00000000); |
| @@ -205,13 +202,9 @@ static cycle_t em_sti_clocksource_read(s |
| |
| static int em_sti_clocksource_enable(struct clocksource *cs) |
| { |
| - int ret; |
| struct em_sti_priv *p = cs_to_em_sti(cs); |
| |
| - ret = em_sti_start(p, USER_CLOCKSOURCE); |
| - if (!ret) |
| - __clocksource_update_freq_hz(cs, p->rate); |
| - return ret; |
| + return em_sti_start(p, USER_CLOCKSOURCE); |
| } |
| |
| static void em_sti_clocksource_disable(struct clocksource *cs) |
| @@ -240,8 +233,7 @@ static int em_sti_register_clocksource(s |
| |
| dev_info(&p->pdev->dev, "used as clock source\n"); |
| |
| - /* Register with dummy 1 Hz value, gets updated in ->enable() */ |
| - clocksource_register_hz(cs, 1); |
| + clocksource_register_hz(cs, p->rate); |
| return 0; |
| } |
| |
| @@ -263,7 +255,6 @@ static int em_sti_clock_event_set_onesho |
| |
| dev_info(&p->pdev->dev, "used for oneshot clock events\n"); |
| em_sti_start(p, USER_CLOCKEVENT); |
| - clockevents_config(&p->ced, p->rate); |
| return 0; |
| } |
| |
| @@ -294,8 +285,7 @@ static void em_sti_register_clockevent(s |
| |
| dev_info(&p->pdev->dev, "used for clock events\n"); |
| |
| - /* Register with dummy 1 Hz value, gets updated in ->set_state_oneshot() */ |
| - clockevents_config_and_register(ced, 1, 2, 0xffffffff); |
| + clockevents_config_and_register(ced, p->rate, 2, 0xffffffff); |
| } |
| |
| static int em_sti_probe(struct platform_device *pdev) |
| @@ -344,6 +334,15 @@ static int em_sti_probe(struct platform_ |
| return ret; |
| } |
| |
| + ret = clk_enable(p->clk); |
| + if (ret < 0) { |
| + dev_err(&p->pdev->dev, "cannot enable clock\n"); |
| + clk_unprepare(p->clk); |
| + return ret; |
| + } |
| + p->rate = clk_get_rate(p->clk); |
| + clk_disable(p->clk); |
| + |
| raw_spin_lock_init(&p->lock); |
| em_sti_register_clockevent(p); |
| em_sti_register_clocksource(p); |