Re: [PATCH] mach-pxa/viper: Fix timeout usage for I2C

[Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>]

On Tue, 13 Apr 2010 01:57:51 +0800, Eric Miao wrote:
> On Sun, Apr 4, 2010 at 10:08 PM, Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:
> > The timeout value is in jiffies, so it should be using HZ, not a plain
> > number. Assume '100' means 100ms here and adapt accordingly.
> >
> > Signed-off-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > Cc: Eric Miao <eric.y.miao-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > Cc: Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
> > Cc: Marc Zyngier <maz-20xNzvSXLT6hUMvJH42dtQ@public.gmane.org>
> > Cc: Paul Shen <paul.shen-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
> > Cc: Mike Rapoport <mike-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>
> > ---
> >
> > Janitorial fix, not tested due to no hardware.
> >
> >  arch/arm/mach-pxa/viper.c |    5 +++--
> >  1 files changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/mach-pxa/viper.c b/arch/arm/mach-pxa/viper.c
> > index 1dd1334..c25921f 100644
> > --- a/arch/arm/mach-pxa/viper.c
> > +++ b/arch/arm/mach-pxa/viper.c
> > @@ -33,6 +33,7 @@
> >  #include <linux/pm.h>
> >  #include <linux/sched.h>
> >  #include <linux/gpio.h>
> > +#include <linux/jiffies.h>
> >  #include <linux/i2c-gpio.h>
> >  #include <linux/serial_8250.h>
> >  #include <linux/smc91x.h>
> > @@ -453,7 +454,7 @@ static struct i2c_gpio_platform_data i2c_bus_data = {
> >        .sda_pin = VIPER_RTC_I2C_SDA_GPIO,
> >        .scl_pin = VIPER_RTC_I2C_SCL_GPIO,
> >        .udelay  = 10,
> > -       .timeout = 100,
> > +       .timeout = HZ / 10,
> >  };
> >
> >  static struct platform_device i2c_bus_device = {
> > @@ -778,7 +779,7 @@ static void __init viper_tpm_init(void)
> >                .sda_pin = VIPER_TPM_I2C_SDA_GPIO,
> >                .scl_pin = VIPER_TPM_I2C_SCL_GPIO,
> >                .udelay  = 10,
> > -               .timeout = 100,
> > +               .timeout = HZ / 10,
> >        };
> >        char *errstr;
> >
> 
> One other better and cleaner approach to such inconsistency issue is
> to have a timeout_ms field, and having i2c-gpio.c driver to convert this
> to jiffies using msec_to_jiffies() at run-time.

With what benefit? Expressing time values in units of HZ is very
frequent in the kernel code and shouldn't actually surprise anyone.

-- 
Jean Delvare