Messages in this thread | | | Date | Tue, 25 Mar 2014 12:11:59 +0000 | From | Ian Abbott <> | Subject | Re: [PATCH] staging: comedi: s626: use comedi_timeout() on remaining loops |
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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@yahoo.com>
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@mev.co.uk> )=- -=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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