staging: comedi: s626: use comedi_timeout()

Use comedi_timeout() to wait for the analog input end-of-conversion.

This prevents a deadlock condition that could occur by providing a
timeout in case the end-of-conversion does not happen.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/s626.c b/drivers/staging/comedi/drivers/s626.c
index 9e711ee13bb7902ed2f7c1ab96d5337035025c8c..5ba4b4ae6507faa941ed6617ac269343643349e4 100644 (file)
--- a/drivers/staging/comedi/drivers/s626.c
+++ b/drivers/staging/comedi/drivers/s626.c
@@ -1846,6 +1846,20 @@ static int s626_ai_rinsn(struct comedi_device *dev,
 }
 #endif
 
+static int s626_ai_eoc(struct comedi_device *dev,
+                      struct comedi_subdevice *s,
+                      struct comedi_insn *insn,
+                      unsigned long context)
+{
+       struct s626_private *devpriv = dev->private;
+       unsigned int status;
+
+       status = readl(devpriv->mmio + S626_P_PSR);
+       if (status & S626_PSR_GPIO2)
+               return 0;
+       return -EBUSY;
+}
+
 static int s626_ai_insn_read(struct comedi_device *dev,
                             struct comedi_subdevice *s,
                             struct comedi_insn *insn, unsigned int *data)
@@ -1856,6 +1870,7 @@ static int s626_ai_insn_read(struct comedi_device *dev,
        uint16_t adc_spec = 0;
        uint32_t gpio_image;
        uint32_t tmp;
+       int ret;
        int n;
 
        /*
@@ -1897,8 +1912,9 @@ static int s626_ai_insn_read(struct comedi_device *dev,
                 */
 
                /* Wait for ADC done */
-               while (!(readl(devpriv->mmio + S626_P_PSR) & S626_PSR_GPIO2))
-                       ;
+               ret = comedi_timeout(dev, s, insn, s626_ai_eoc, 0);
+               if (ret)
+                       return ret;
 
                /* Fetch ADC data */
                if (n != 0) {