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Message-Id: <1409569440-10979-29-git-send-email-abbotti@mev.co.uk>
Date: Mon, 1 Sep 2014 12:04:00 +0100
From: Ian Abbott <abbotti@....co.uk>
To: driverdev-devel@...uxdriverproject.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Ian Abbott <abbotti@....co.uk>,
H Hartley Sweeten <hartleys@...ionengravers.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH 28/28] staging: comedi: amplc_pci230: simplify interrupt enable handling
`struct pci230_private` has two members to manage the enabled interrupt
sources. `int_en` is the interrupt sources we want to be enabled and
`ier` is a shadow of the write-only interrupt enable register. They
have the same value most of the time. They differ in the interrupt
handler (`pci230_interrupt()`) itself when it temporarily clears bits in
the interrupt enable register and the `ier` member in order to unlatch
them in hardware, but leaves the `int_en` member alone. They also
differ in `pci230_ai_stop()` and `pci230_ao_stop()` which clear bits in
the `int_en` member and wait for the interrupt handler to finish before
copying the value to the `ier` member and the interrupt enable register.
Simplify the handling a bit, by making the `ier` member take on the role
of the `int_en` member, and allowing the value to differ from the
interrupt enable register while the interrupt handler is running.
Signed-off-by: Ian Abbott <abbotti@....co.uk>
---
drivers/staging/comedi/drivers/amplc_pci230.c | 32 +++++++++------------------
1 file changed, 10 insertions(+), 22 deletions(-)
diff --git a/drivers/staging/comedi/drivers/amplc_pci230.c b/drivers/staging/comedi/drivers/amplc_pci230.c
index 7748e17..66e7a47 100644
--- a/drivers/staging/comedi/drivers/amplc_pci230.c
+++ b/drivers/staging/comedi/drivers/amplc_pci230.c
@@ -499,8 +499,7 @@ struct pci230_private {
unsigned short daccon; /* DACCON register value */
unsigned short adcfifothresh; /* ADC FIFO threshold (PCI230+/260+) */
unsigned short adcg; /* ADCG register value */
- unsigned char int_en; /* Interrupt enable bits */
- unsigned char ier; /* Copy of interrupt enable register */
+ unsigned char ier; /* Interrupt enable bits */
unsigned char res_owned[NUM_OWNERS]; /* Owned resources */
bool intr_running:1; /* Flag set in interrupt routine */
bool ai_bipolar:1; /* Flag AI range is bipolar */
@@ -1049,15 +1048,12 @@ static void pci230_ao_stop(struct comedi_device *dev,
* unless we are called from the interrupt routine.
*/
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
- devpriv->int_en &= ~intsrc;
+ devpriv->ier &= ~intsrc;
while (devpriv->intr_running && devpriv->intr_cpuid != THISCPU) {
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
}
- if (devpriv->ier != devpriv->int_en) {
- devpriv->ier = devpriv->int_en;
- outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
- }
+ outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
if (devpriv->hwver >= 2) {
/*
@@ -1311,7 +1307,6 @@ static void pci230_ao_start(struct comedi_device *dev,
/* Not using DAC FIFO. */
/* Enable CT1 timer interrupt. */
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
- devpriv->int_en |= PCI230_INT_ZCLK_CT1;
devpriv->ier |= PCI230_INT_ZCLK_CT1;
outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
spin_unlock_irqrestore(&devpriv->isr_spinlock,
@@ -1327,7 +1322,6 @@ static void pci230_ao_start(struct comedi_device *dev,
if (devpriv->hwver >= 2) {
/* Using DAC FIFO. Enable DAC FIFO interrupt. */
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
- devpriv->int_en |= PCI230P2_INT_DAC;
devpriv->ier |= PCI230P2_INT_DAC;
outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
@@ -1892,15 +1886,12 @@ static void pci230_ai_stop(struct comedi_device *dev,
* Disable ADC interrupt and wait for interrupt routine to finish
* running unless we are called from the interrupt routine.
*/
- devpriv->int_en &= ~PCI230_INT_ADC;
+ devpriv->ier &= ~PCI230_INT_ADC;
while (devpriv->intr_running && devpriv->intr_cpuid != THISCPU) {
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
}
- if (devpriv->ier != devpriv->int_en) {
- devpriv->ier = devpriv->int_en;
- outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
- }
+ outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
/*
* Reset FIFO, disable FIFO and set start conversion source to none.
@@ -1935,7 +1926,6 @@ static void pci230_ai_start(struct comedi_device *dev,
/* Enable ADC FIFO trigger level interrupt. */
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
- devpriv->int_en |= PCI230_INT_ADC;
devpriv->ier |= PCI230_INT_ADC;
outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
@@ -2379,7 +2369,7 @@ static int pci230_ai_cancel(struct comedi_device *dev,
/* Interrupt handler */
static irqreturn_t pci230_interrupt(int irq, void *d)
{
- unsigned char status_int, valid_status_int;
+ unsigned char status_int, valid_status_int, temp_ier;
struct comedi_device *dev = (struct comedi_device *)d;
struct pci230_private *devpriv = dev->private;
struct comedi_subdevice *s;
@@ -2392,14 +2382,14 @@ static irqreturn_t pci230_interrupt(int irq, void *d)
return IRQ_NONE;
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
- valid_status_int = devpriv->int_en & status_int;
+ valid_status_int = devpriv->ier & status_int;
/*
* Disable triggered interrupts.
* (Only those interrupts that need re-enabling, are, later in the
* handler).
*/
- devpriv->ier = devpriv->int_en & ~status_int;
- outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
+ temp_ier = devpriv->ier & ~status_int;
+ outb(temp_ier, dev->iobase + PCI230_INT_SCE);
devpriv->intr_running = true;
devpriv->intr_cpuid = THISCPU;
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
@@ -2432,10 +2422,8 @@ static irqreturn_t pci230_interrupt(int irq, void *d)
/* Reenable interrupts. */
spin_lock_irqsave(&devpriv->isr_spinlock, irqflags);
- if (devpriv->ier != devpriv->int_en) {
- devpriv->ier = devpriv->int_en;
+ if (devpriv->ier != temp_ier)
outb(devpriv->ier, dev->iobase + PCI230_INT_SCE);
- }
devpriv->intr_running = false;
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);
--
2.0.4
--
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