mfd: t7l66xb: Make use of raw_spinlock variants

The t7l66xb mfd driver currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/t7l66xb.c b/drivers/mfd/t7l66xb.c
index 94bd89cb1f0618581d3f190f2decb1e6b8a0ef7e..22c811396edcf95363c5110896096d51bb6180ee 100644 (file)
--- a/drivers/mfd/t7l66xb.c
+++ b/drivers/mfd/t7l66xb.c
@@ -69,7 +69,7 @@ static const struct resource t7l66xb_mmc_resources[] = {
 struct t7l66xb {
        void __iomem            *scr;
        /* Lock to protect registers requiring read/modify/write ops. */
-       spinlock_t              lock;
+       raw_spinlock_t          lock;
 
        struct resource         rscr;
        struct clk              *clk48m;
@@ -89,13 +89,13 @@ static int t7l66xb_mmc_enable(struct platform_device *mmc)
 
        clk_prepare_enable(t7l66xb->clk32k);
 
-       spin_lock_irqsave(&t7l66xb->lock, flags);
+       raw_spin_lock_irqsave(&t7l66xb->lock, flags);
 
        dev_ctl = tmio_ioread8(t7l66xb->scr + SCR_DEV_CTL);
        dev_ctl |= SCR_DEV_CTL_MMC;
        tmio_iowrite8(dev_ctl, t7l66xb->scr + SCR_DEV_CTL);
 
-       spin_unlock_irqrestore(&t7l66xb->lock, flags);
+       raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
 
        tmio_core_mmc_enable(t7l66xb->scr + 0x200, 0,
                t7l66xb_mmc_resources[0].start & 0xfffe);
@@ -110,13 +110,13 @@ static int t7l66xb_mmc_disable(struct platform_device *mmc)
        unsigned long flags;
        u8 dev_ctl;
 
-       spin_lock_irqsave(&t7l66xb->lock, flags);
+       raw_spin_lock_irqsave(&t7l66xb->lock, flags);
 
        dev_ctl = tmio_ioread8(t7l66xb->scr + SCR_DEV_CTL);
        dev_ctl &= ~SCR_DEV_CTL_MMC;
        tmio_iowrite8(dev_ctl, t7l66xb->scr + SCR_DEV_CTL);
 
-       spin_unlock_irqrestore(&t7l66xb->lock, flags);
+       raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
 
        clk_disable_unprepare(t7l66xb->clk32k);
 
@@ -206,11 +206,11 @@ static void t7l66xb_irq_mask(struct irq_data *data)
        unsigned long                   flags;
        u8 imr;
 
-       spin_lock_irqsave(&t7l66xb->lock, flags);
+       raw_spin_lock_irqsave(&t7l66xb->lock, flags);
        imr = tmio_ioread8(t7l66xb->scr + SCR_IMR);
        imr |= 1 << (data->irq - t7l66xb->irq_base);
        tmio_iowrite8(imr, t7l66xb->scr + SCR_IMR);
-       spin_unlock_irqrestore(&t7l66xb->lock, flags);
+       raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
 }
 
 static void t7l66xb_irq_unmask(struct irq_data *data)
@@ -219,11 +219,11 @@ static void t7l66xb_irq_unmask(struct irq_data *data)
        unsigned long flags;
        u8 imr;
 
-       spin_lock_irqsave(&t7l66xb->lock, flags);
+       raw_spin_lock_irqsave(&t7l66xb->lock, flags);
        imr = tmio_ioread8(t7l66xb->scr + SCR_IMR);
        imr &= ~(1 << (data->irq - t7l66xb->irq_base));
        tmio_iowrite8(imr, t7l66xb->scr + SCR_IMR);
-       spin_unlock_irqrestore(&t7l66xb->lock, flags);
+       raw_spin_unlock_irqrestore(&t7l66xb->lock, flags);
 }
 
 static struct irq_chip t7l66xb_chip = {
@@ -321,7 +321,7 @@ static int t7l66xb_probe(struct platform_device *dev)
        if (!t7l66xb)
                return -ENOMEM;
 
-       spin_lock_init(&t7l66xb->lock);
+       raw_spin_lock_init(&t7l66xb->lock);
 
        platform_set_drvdata(dev, t7l66xb);