PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped

There is no real need to keep interrupt always-enabled, will be nicer
to keep it disabled while governor is inactive.

Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index a27300f..a0a5f3f 100644 (file)
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -11,6 +11,7 @@
 #include <linux/devfreq.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
@@ -416,8 +417,6 @@ static void tegra_actmon_start(struct tegra_devfreq *tegra)
 {
        unsigned int i;
 
-       disable_irq(tegra->irq);
-
        actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
                      ACTMON_GLB_PERIOD_CTRL);
 
@@ -442,8 +441,6 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
        }
 
        actmon_write_barrier(tegra);
-
-       enable_irq(tegra->irq);
 }
 
 static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
@@ -552,6 +549,12 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
 {
        struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
 
+       /*
+        * Couple devfreq-device with the governor early because it is
+        * needed at the moment of governor's start (used by ISR).
+        */
+       tegra->devfreq = devfreq;
+
        switch (event) {
        case DEVFREQ_GOV_START:
                devfreq_monitor_start(devfreq);
@@ -586,10 +589,11 @@ static struct devfreq_governor tegra_devfreq_governor = {
 
 static int tegra_devfreq_probe(struct platform_device *pdev)
 {
-       struct tegra_devfreq *tegra;
        struct tegra_devfreq_device *dev;
-       unsigned int i;
+       struct tegra_devfreq *tegra;
+       struct devfreq *devfreq;
        unsigned long rate;
+       unsigned int i;
        int err;
 
        tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
@@ -625,6 +629,16 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
        }
        tegra->irq = err;
 
+       irq_set_status_flags(tegra->irq, IRQ_NOAUTOEN);
+
+       err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
+                                       actmon_thread_isr, IRQF_ONESHOT,
+                                       "tegra-devfreq", tegra);
+       if (err) {
+               dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
+               return err;
+       }
+
        reset_control_assert(tegra->reset);
 
        err = clk_prepare_enable(tegra->clock);
@@ -672,28 +686,15 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
        }
 
        tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
-       tegra->devfreq = devfreq_add_device(&pdev->dev,
-                                           &tegra_devfreq_profile,
-                                           "tegra_actmon",
-                                           NULL);
-       if (IS_ERR(tegra->devfreq)) {
-               err = PTR_ERR(tegra->devfreq);
+       devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
+                                    "tegra_actmon", NULL);
+       if (IS_ERR(devfreq)) {
+               err = PTR_ERR(devfreq);
                goto remove_governor;
        }
 
-       err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
-                                       actmon_thread_isr, IRQF_ONESHOT,
-                                       "tegra-devfreq", tegra);
-       if (err) {
-               dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
-               goto remove_devfreq;
-       }
-
        return 0;
 
-remove_devfreq:
-       devfreq_remove_device(tegra->devfreq);
-
 remove_governor:
        devfreq_remove_governor(&tegra_devfreq_governor);