drivers/clocksource/timer-ti-dm: Don't call clk_get_rate() in stop function

[ Upstream commit 12590d4d0e331d3cb9e6b3494515cd61c8a6624e ]

clk_get_rate() might sleep, and that prevents dm-timer based PWM from being
used from atomic context.

Fix that by getting fclk rate in probe() and using a notifier in case rate
changes.

Fixes: af04aa856e93 ("ARM: OMAP: Move dmtimer driver out of plat-omap to drivers under clocksource")
Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1696312220-11550-1-git-send-email-ivo.g.dimitrov.75@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c
index 09ab29c..5f60f6b 100644 (file)
--- a/drivers/clocksource/timer-ti-dm.c
+++ b/drivers/clocksource/timer-ti-dm.c
@@ -140,6 +140,8 @@ struct dmtimer {
        struct platform_device *pdev;
        struct list_head node;
        struct notifier_block nb;
+       struct notifier_block fclk_nb;
+       unsigned long fclk_rate;
 };
 
 static u32 omap_reserved_systimers;
@@ -253,8 +255,7 @@ static inline void __omap_dm_timer_enable_posted(struct dmtimer *timer)
        timer->posted = OMAP_TIMER_POSTED;
 }
 
-static inline void __omap_dm_timer_stop(struct dmtimer *timer,
-                                       unsigned long rate)
+static inline void __omap_dm_timer_stop(struct dmtimer *timer)
 {
        u32 l;
 
@@ -269,7 +270,7 @@ static inline void __omap_dm_timer_stop(struct dmtimer *timer,
                 * Wait for functional clock period x 3.5 to make sure that
                 * timer is stopped
                 */
-               udelay(3500000 / rate + 1);
+               udelay(3500000 / timer->fclk_rate + 1);
 #endif
        }
 
@@ -348,6 +349,21 @@ static int omap_timer_context_notifier(struct notifier_block *nb,
        return NOTIFY_OK;
 }
 
+static int omap_timer_fclk_notifier(struct notifier_block *nb,
+                                   unsigned long event, void *data)
+{
+       struct clk_notifier_data *clk_data = data;
+       struct dmtimer *timer = container_of(nb, struct dmtimer, fclk_nb);
+
+       switch (event) {
+       case POST_RATE_CHANGE:
+               timer->fclk_rate = clk_data->new_rate;
+               return NOTIFY_OK;
+       default:
+               return NOTIFY_DONE;
+       }
+}
+
 static int omap_dm_timer_reset(struct dmtimer *timer)
 {
        u32 l, timeout = 100000;
@@ -754,7 +770,6 @@ static int omap_dm_timer_stop(struct omap_dm_timer *cookie)
 {
        struct dmtimer *timer;
        struct device *dev;
-       unsigned long rate = 0;
 
        timer = to_dmtimer(cookie);
        if (unlikely(!timer))
@@ -762,10 +777,7 @@ static int omap_dm_timer_stop(struct omap_dm_timer *cookie)
 
        dev = &timer->pdev->dev;
 
-       if (!timer->omap1)
-               rate = clk_get_rate(timer->fclk);
-
-       __omap_dm_timer_stop(timer, rate);
+       __omap_dm_timer_stop(timer);
 
        pm_runtime_put_sync(dev);
 
@@ -1124,6 +1136,14 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
                timer->fclk = devm_clk_get(dev, "fck");
                if (IS_ERR(timer->fclk))
                        return PTR_ERR(timer->fclk);
+
+               timer->fclk_nb.notifier_call = omap_timer_fclk_notifier;
+               ret = devm_clk_notifier_register(dev, timer->fclk,
+                                                &timer->fclk_nb);
+               if (ret)
+                       return ret;
+
+               timer->fclk_rate = clk_get_rate(timer->fclk);
        } else {
                timer->fclk = ERR_PTR(-ENODEV);
        }