Re: [PATCH] staging: comedi: s626: use comedi_timeout() on remaining loops
From: Ian Abbott
Date: Tue Mar 25 2014 - 08:12:58 EST
On 2014-03-25 05:09, Chase Southwood wrote:
There were just a handful of more while loops in this file that need timeouts,
and this patch takes care of them, using comedi_timeout(). A couple of new
callbacks are introduced, but there was one case where the appropriate callback
function was already defined; in this case I have just used that.
Signed-off-by: Chase Southwood <chase.southwood@xxxxxxxxx>
I think it can be simplified a bit as described below.
---
drivers/staging/comedi/drivers/s626.c | 66 ++++++++++++++++++++++++++++++-----
1 file changed, 58 insertions(+), 8 deletions(-)
diff --git a/drivers/staging/comedi/drivers/s626.c b/drivers/staging/comedi/drivers/s626.c
index 95fadf3..4dc5659 100644
--- a/drivers/staging/comedi/drivers/s626.c
+++ b/drivers/staging/comedi/drivers/s626.c
@@ -295,10 +295,24 @@ static void s626_debi_replace(struct comedi_device *dev, unsigned int addr,
/* ************** EEPROM ACCESS FUNCTIONS ************** */
+static int s626_i2c_handshake_eoc(struct comedi_device *dev,
+ struct comedi_subdevice *s,
+ struct comedi_insn *insn,
+ unsigned long context)
+{
+ unsigned int status;
+
+ status = s626_mc_test(dev, S626_MC2_UPLD_IIC, S626_P_MC2);
+ if (status)
+ return 0;
+ return -EBUSY;
+}
+
So s626_i2c_handshake_eoc() tests the S626_MC2_UPLD_IIC bit of the
S626_P_MC2 register and returns 0 if the bit is high or -EBUSY if it is low.
static uint32_t s626_i2c_handshake(struct comedi_device *dev, uint32_t val)
{
struct s626_private *devpriv = dev->private;
unsigned int ctrl;
+ uint32_t ret;
/* Write I2C command to I2C Transfer Control shadow register */
writel(val, devpriv->mmio + S626_P_I2CCTRL);
@@ -308,8 +322,9 @@ static uint32_t s626_i2c_handshake(struct comedi_device *dev, uint32_t val)
* wait for upload confirmation.
*/
s626_mc_enable(dev, S626_MC2_UPLD_IIC, S626_P_MC2);
- while (!s626_mc_test(dev, S626_MC2_UPLD_IIC, S626_P_MC2))
- ;
+ ret = comedi_timeout(dev, NULL, NULL, s626_i2c_handshake_eoc, 0);
+ if (ret)
+ return ret;
That's fine. Both the original while loop and the comedi_timeout() call
are waiting for the S626_MC_UPLD_IIC bit to go high.
/* Wait until I2C bus transfer is finished or an error occurs */
do {
@@ -2029,8 +2044,9 @@ static int s626_ai_insn_read(struct comedi_device *dev,
/* Wait for the data to arrive in FB BUFFER 1 register. */
/* 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 from audio interface's input shift register. */
@@ -2641,6 +2657,36 @@ static int s626_allocate_dma_buffers(struct comedi_device *dev)
return 0;
}
+enum {
+ s626_initialize_wait_i2c_abort,
+ s626_initialize_wait_i2c_err_reset
+};
+
+static int s626_initialize_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;
+
+ switch (context) {
+ case s626_initialize_wait_i2c_abort:
+ status = readl(devpriv->mmio + S626_P_MC2);
+ if (status & S626_MC2_UPLD_IIC)
+ return 0;
+ break;
The 's626_initialize_wait_i2c_abort' case returns 0 if the
S626_MC2_UPLD_IIC bit is high and the function around it will return
-EBUSY otherwise. That's basically the same as the
s626_i2c_handshake_eoc() callback except it doesn't call s626_mc_test()
to read the register and check the bit, it does it itself.
+ case s626_initialize_wait_i2c_err_reset:
+ status = s626_mc_test(dev, S626_MC2_UPLD_IIC, S626_P_MC2);
+ if (status)
+ return 0;
+ break;
The 's626_initialize_wait_i2c_err_reset' case is also basically the same
as the s626_i2c_handshake_eoc() callback.
+ default:
+ return -EINVAL;
+ }
+ return -EBUSY;
+}
+
It seems both supported context case values of the s626_initialize_eoc()
callback basically do the same thing as the s626_i2c_handshake_eoc()
callback, so you could use that callback instead of this one.
static int s626_initialize(struct comedi_device *dev)
{
struct s626_private *devpriv = dev->private;
@@ -2681,8 +2727,10 @@ static int s626_initialize(struct comedi_device *dev)
writel(S626_I2C_CLKSEL | S626_I2C_ABORT,
devpriv->mmio + S626_P_I2CSTAT);
s626_mc_enable(dev, S626_MC2_UPLD_IIC, S626_P_MC2);
- while (!(readl(devpriv->mmio + S626_P_MC2) & S626_MC2_UPLD_IIC))
- ;
+ ret = comedi_timeout(dev, NULL, NULL, s626_initialize_eoc,
+ s626_initialize_wait_i2c_abort);
+ if (ret)
+ return ret;
That's fine. The original while loop is waiting for the
S626_MC2_UPLD_IIC bit to go high and so is the comedi_timeout() call.
But you could re-use the s626_i2c_handshake_eoc() callback instead of
the s626_initialize_wait_i2c_abort() as described above.
/*
* Per SAA7146 data sheet, write to STATUS
@@ -2691,8 +2739,10 @@ static int s626_initialize(struct comedi_device *dev)
for (i = 0; i < 2; i++) {
writel(S626_I2C_CLKSEL, devpriv->mmio + S626_P_I2CSTAT);
s626_mc_enable(dev, S626_MC2_UPLD_IIC, S626_P_MC2);
- while (!s626_mc_test(dev, S626_MC2_UPLD_IIC, S626_P_MC2))
- ;
+ ret = comedi_timeout(dev, NULL, NULL, s626_initialize_eoc,
+ s626_initialize_wait_i2c_err_reset);
+ if (ret)
+ return ret;
As above, the original while loop is waiting for the S626_MC2_UPLD_IIC
bit to go high, so you could re-use the s626_i2c_handshake_eoc() callback.
}
/*
Best regards,
Ian.
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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