platform-drivers: x86: pmic: Use irq_chip buslock mechanism

The set_type function of the pmic irq chip is a horrible hack. It
schedules work because it cannot access the scu chip from the set_type
function. That breaks the assumption, that the type is set after
set_type has returned.

irq_chips provide buslock functions to avoid the above. Convert the
driver to use the proper model.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Alek Du <alek.du@intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 32 insertions, 48 deletions

diff --git a/drivers/platform/x86/intel_pmic_gpio.c b/drivers/platform/x86/intel_pmic_gpio.c
index 9134d9d07569..df244c83681d 100644
--- a/drivers/platform/x86/intel_pmic_gpio.c
+++ b/drivers/platform/x86/intel_pmic_gpio.c
@@ -60,23 +60,18 @@ enum pmic_gpio_register {
 #define GPOSW_DOU 0x08
 #define GPOSW_RDRV 0x30
 
+#define GPIO_UPDATE_TYPE        0x80000000
 
 #define NUM_GPIO 24
 
-struct pmic_gpio_irq {
-        spinlock_t lock;
-        u32 trigger[NUM_GPIO];
-        u32 dirty;
-        struct work_struct work;
-};
-
-
 struct pmic_gpio {
+        struct mutex            buslock;
         struct gpio_chip        chip;
-        struct pmic_gpio_irq    irqtypes;
         void                    *gpiointr;
         int                     irq;
         unsigned                irq_base;
+        unsigned int            update_type;
+        u32                     trigger_type;
 };
 
 static void pmic_program_irqtype(int gpio, int type)
@@ -92,37 +87,6 @@ static void pmic_program_irqtype(int gpio, int type)
                 intel_scu_ipc_update_register(GPIO0 + gpio, 0x00, 0x10);
 };
 
-static void pmic_irqtype_work(struct work_struct *work)
-{
-        struct pmic_gpio_irq *t =
-                container_of(work, struct pmic_gpio_irq, work);
-        unsigned long flags;
-        int i;
-        u16 type;
-
-        spin_lock_irqsave(&t->lock, flags);
-        /* As we drop the lock, we may need multiple scans if we race the
-           pmic_irq_type function */
-        while (t->dirty) {
-                /*
-                 *      For each pin that has the dirty bit set send an IPC
-                 *      message to configure the hardware via the PMIC
-                 */
-                for (i = 0; i < NUM_GPIO; i++) {
-                        if (!(t->dirty & (1 << i)))
-                                continue;
-                        t->dirty &= ~(1 << i);
-                        /* We can't trust the array entry or dirty
-                           once the lock is dropped */
-                        type = t->trigger[i];
-                        spin_unlock_irqrestore(&t->lock, flags);
-                        pmic_program_irqtype(i, type);
-                        spin_lock_irqsave(&t->lock, flags);
-                }
-        }
-        spin_unlock_irqrestore(&t->lock, flags);
-}
-
 static int pmic_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 {
         if (offset > 8) {
@@ -190,20 +154,21 @@ static void pmic_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
                         1 << (offset - 16));
 }
 
+/*
+ * This is called from genirq with pg->buslock locked and
+ * irq_desc->lock held. We can not access the scu bus here, so we
+ * store the change and update in the bus_sync_unlock() function below
+ */
 static int pmic_irq_type(struct irq_data *data, unsigned type)
 {
         struct pmic_gpio *pg = irq_data_get_irq_chip_data(data);
         u32 gpio = data->irq - pg->irq_base;
-        unsigned long flags;
 
         if (gpio >= pg->chip.ngpio)
                 return -EINVAL;
 
-        spin_lock_irqsave(&pg->irqtypes.lock, flags);
-        pg->irqtypes.trigger[gpio] = type;
-        pg->irqtypes.dirty |=  (1 << gpio);
-        spin_unlock_irqrestore(&pg->irqtypes.lock, flags);
-        schedule_work(&pg->irqtypes.work);
+        pg->trigger_type = type;
+        pg->update_type = gpio | GPIO_UPDATE_TYPE;
         return 0;
 }
 
@@ -214,6 +179,26 @@ static int pmic_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
         return pg->irq_base + offset;
 }
 
+static void pmic_bus_lock(struct irq_data *data)
+{
+        struct pmic_gpio *pg = irq_data_get_irq_chip_data(data);
+
+        mutex_lock(&pg->buslock);
+}
+
+static void pmic_bus_sync_unlock(struct irq_data *data)
+{
+        struct pmic_gpio *pg = irq_data_get_irq_chip_data(data);
+
+        if (pg->update_type) {
+                unsigned int gpio = pg->update_type & ~GPIO_UPDATE_TYPE;
+
+                pmic_program_irqtype(gpio, pg->trigger_type);
+                pg->update_type = 0;
+        }
+        mutex_unlock(&pg->buslock);
+}
+
 /* the gpiointr register is read-clear, so just do nothing. */
 static void pmic_irq_unmask(struct irq_data *data) { }
 
@@ -287,8 +272,7 @@ static int __devinit platform_pmic_gpio_probe(struct platform_device *pdev)
         pg->chip.can_sleep = 1;
         pg->chip.dev = dev;
 
-        INIT_WORK(&pg->irqtypes.work, pmic_irqtype_work);
-        spin_lock_init(&pg->irqtypes.lock);
+        mutex_init(&pg->buslock);
 
         pg->chip.dev = dev;
         retval = gpiochip_add(&pg->chip);