greybus: arche-platform: Rework platform/wd-line state transition logic

This patch simplifies and improves the readability of the internal state
transition logic of arche platform driver state transition logic by:

1. Making a dedicated function to state-transition the platform code.
2. Condense the decision to swtich states down to a single switch
   statement instead of four separate if/else clauses.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Suggested-by: Alex Elder <elder@linaro.org>
Reviewed-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
index 4eceec39ae993632c7a6ef25b576f554ab7059b0..83d823cf5232c082d08b3b98681cb4aba8f93ed5 100644 (file)
--- a/drivers/staging/greybus/arche-platform.c
+++ b/drivers/staging/greybus/arche-platform.c
@@ -63,6 +63,13 @@ struct arche_platform_drvdata {
        struct device *dev;
 };
 
+/* Requires calling context to hold arche_pdata->spinlock */
+static void arche_platform_set_state(struct arche_platform_drvdata *arche_pdata,
+                                    enum arche_platform_state state)
+{
+       arche_pdata->state = state;
+}
+
 /*
  * arche_platform_change_state: Change the operational state
  *
@@ -122,22 +129,26 @@ int arche_platform_change_state(enum arche_platform_state state)
                goto exit;
        }
 
-       if (arche_pdata->state == ARCHE_PLATFORM_STATE_OFF ||
-           arche_pdata->state == ARCHE_PLATFORM_STATE_STANDBY ||
-           arche_pdata->state == ARCHE_PLATFORM_STATE_FW_FLASHING) {
-               dev_err(arche_pdata->dev, "busy, request to retry later\n");
-               goto exit;
-       }
-
-       if (state == ARCHE_PLATFORM_STATE_TIME_SYNC) {
+       switch (state) {
+       case ARCHE_PLATFORM_STATE_TIME_SYNC:
                disable_irq(arche_pdata->wake_detect_irq);
-               arche_pdata->state = ARCHE_PLATFORM_STATE_TIME_SYNC;
-       } else if (state == ARCHE_PLATFORM_STATE_ACTIVE) {
-               arche_pdata->state = ARCHE_PLATFORM_STATE_ACTIVE;
+               break;
+       case ARCHE_PLATFORM_STATE_ACTIVE:
                enable_irq(arche_pdata->wake_detect_irq);
-       } else {
-               dev_err(arche_pdata->dev, "invalid state transition request\n");
+               break;
+       case ARCHE_PLATFORM_STATE_OFF:
+       case ARCHE_PLATFORM_STATE_STANDBY:
+       case ARCHE_PLATFORM_STATE_FW_FLASHING:
+               dev_err(arche_pdata->dev, "busy, request to retry later\n");
+               goto exit;
+       default:
+               ret = -EINVAL;
+               dev_err(arche_pdata->dev,
+                       "invalid state transition request\n");
+               goto exit;
        }
+       arche_platform_set_state(arche_pdata, state);
+       ret = 0;
 exit:
        spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
        mutex_unlock(&arche_pdata->platform_state_mutex);
@@ -146,6 +157,14 @@ exit:
 }
 EXPORT_SYMBOL_GPL(arche_platform_change_state);
 
+/* Requires arche_pdata->wake_lock is held by calling context */
+static void arche_platform_set_wake_detect_state(
+                               struct arche_platform_drvdata *arche_pdata,
+                               enum svc_wakedetect_state state)
+{
+       arche_pdata->wake_detect_state = state;
+}
+
 static inline void svc_reset_onoff(unsigned int gpio, bool onoff)
 {
        gpio_set_value(gpio, onoff);
@@ -208,7 +227,8 @@ static irqreturn_t arche_platform_wd_irq_thread(int irq, void *devid)
                return IRQ_HANDLED;
        }
 
-       arche_pdata->wake_detect_state = WD_STATE_COLDBOOT_START;
+       arche_platform_set_wake_detect_state(arche_pdata,
+                                            WD_STATE_COLDBOOT_START);
        spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
 
        /* It should complete power cycle, so first make sure it is poweroff */
@@ -222,7 +242,7 @@ static irqreturn_t arche_platform_wd_irq_thread(int irq, void *devid)
                dev_warn(arche_pdata->dev, "failed to control hub device\n");
 
        spin_lock_irqsave(&arche_pdata->wake_lock, flags);
-       arche_pdata->wake_detect_state = WD_STATE_IDLE;
+       arche_platform_set_wake_detect_state(arche_pdata, WD_STATE_IDLE);
        spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
 
        return IRQ_HANDLED;
@@ -247,13 +267,14 @@ static irqreturn_t arche_platform_wd_irq(int irq, void *devid)
                        if (time_before(jiffies,
                                        arche_pdata->wake_detect_start +
                                        msecs_to_jiffies(WD_COLDBOOT_PULSE_WIDTH_MS))) {
-                               arche_pdata->wake_detect_state = WD_STATE_IDLE;
+                               arche_platform_set_wake_detect_state(arche_pdata,
+                                                                    WD_STATE_IDLE);
                        } else {
                                /* Check we are not in middle of irq thread already */
                                if (arche_pdata->wake_detect_state !=
                                                WD_STATE_COLDBOOT_START) {
-                                       arche_pdata->wake_detect_state =
-                                               WD_STATE_COLDBOOT_TRIG;
+                                       arche_platform_set_wake_detect_state(arche_pdata,
+                                                                            WD_STATE_COLDBOOT_TRIG);
                                        spin_unlock_irqrestore(
                                                &arche_pdata->wake_lock,
                                                flags);
@@ -270,7 +291,8 @@ static irqreturn_t arche_platform_wd_irq(int irq, void *devid)
                         * it is meant for coldboot and set the flag. If wake/detect line stays low
                         * beyond 30msec, then it is coldboot else fallback to standby boot.
                         */
-                       arche_pdata->wake_detect_state = WD_STATE_BOOT_INIT;
+                       arche_platform_set_wake_detect_state(arche_pdata,
+                                                            WD_STATE_BOOT_INIT);
                }
        }
 
@@ -308,7 +330,7 @@ static int arche_platform_coldboot_seq(struct arche_platform_drvdata *arche_pdat
        svc_reset_onoff(arche_pdata->svc_reset_gpio,
                        !arche_pdata->is_reset_act_hi);
 
-       arche_pdata->state = ARCHE_PLATFORM_STATE_ACTIVE;
+       arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_ACTIVE);
 
        return 0;
 }
@@ -332,7 +354,7 @@ static void arche_platform_fw_flashing_seq(struct arche_platform_drvdata *arche_
        svc_reset_onoff(arche_pdata->svc_reset_gpio,
                        !arche_pdata->is_reset_act_hi);
 
-       arche_pdata->state = ARCHE_PLATFORM_STATE_FW_FLASHING;
+       arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_FW_FLASHING);
 
 }
 
@@ -353,7 +375,8 @@ static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pda
                gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
                usleep_range(100, 200);
                spin_lock_irqsave(&arche_pdata->wake_lock, flags);
-               arche_pdata->wake_detect_state = WD_STATE_IDLE;
+               arche_platform_set_wake_detect_state(arche_pdata,
+                                                    WD_STATE_IDLE);
                spin_unlock_irqrestore(&arche_pdata->wake_lock, flags);
 
                clk_disable_unprepare(arche_pdata->svc_ref_clk);
@@ -363,7 +386,7 @@ static void arche_platform_poweroff_seq(struct arche_platform_drvdata *arche_pda
        svc_reset_onoff(arche_pdata->svc_reset_gpio,
                        arche_pdata->is_reset_act_hi);
 
-       arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;
+       arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_OFF);
 }
 
 static ssize_t state_store(struct device *dev,
@@ -502,7 +525,7 @@ static int arche_platform_probe(struct platform_device *pdev)
                dev_err(dev, "failed to set svc-reset gpio dir:%d\n", ret);
                return ret;
        }
-       arche_pdata->state = ARCHE_PLATFORM_STATE_OFF;
+       arche_platform_set_state(arche_pdata, ARCHE_PLATFORM_STATE_OFF);
 
        arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np,
                                        "svc,sysboot-gpio", 0);
@@ -567,7 +590,7 @@ static int arche_platform_probe(struct platform_device *pdev)
        }
        /* deassert wake detect */
        gpio_direction_output(arche_pdata->wake_detect_gpio, 0);
-       arche_pdata->wake_detect_state = WD_STATE_IDLE;
+       arche_platform_set_wake_detect_state(arche_pdata, WD_STATE_IDLE);
 
        arche_pdata->dev = &pdev->dev;