From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Miao <eric.y.miao-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH] mach-pxa/viper: Fix timeout usage for I2C
Date: Tue, 13 Apr 2010 01:57:51 +0800
Message-ID: <m2rf17812d71004121057n5131d025pb4965f45b61271f@mail.gmail.com>
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To: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>, Marc Zyngier <maz-20xNzvSXLT6hUMvJH42dtQ@public.gmane.org>, Paul Shen <paul.shen-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Mike Rapoport <mike-UTxiZqZC01RS1MOuV/RT9w@public.gmane.org>
List-Id: linux-i2c@vger.kernel.org

On Sun, Apr 4, 2010 at 10:08 PM, Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> w=
rote:
> The timeout value is in jiffies, so it should be using HZ, not a plai=
n
> 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.
>
> =C2=A0arch/arm/mach-pxa/viper.c | =C2=A0 =C2=A05 +++--
> =C2=A01 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 @@
> =C2=A0#include <linux/pm.h>
> =C2=A0#include <linux/sched.h>
> =C2=A0#include <linux/gpio.h>
> +#include <linux/jiffies.h>
> =C2=A0#include <linux/i2c-gpio.h>
> =C2=A0#include <linux/serial_8250.h>
> =C2=A0#include <linux/smc91x.h>
> @@ -453,7 +454,7 @@ static struct i2c_gpio_platform_data i2c_bus_data=
 =3D {
> =C2=A0 =C2=A0 =C2=A0 =C2=A0.sda_pin =3D VIPER_RTC_I2C_SDA_GPIO,
> =C2=A0 =C2=A0 =C2=A0 =C2=A0.scl_pin =3D VIPER_RTC_I2C_SCL_GPIO,
> =C2=A0 =C2=A0 =C2=A0 =C2=A0.udelay =C2=A0=3D 10,
> - =C2=A0 =C2=A0 =C2=A0 .timeout =3D 100,
> + =C2=A0 =C2=A0 =C2=A0 .timeout =3D HZ / 10,
> =C2=A0};
>
> =C2=A0static struct platform_device i2c_bus_device =3D {
> @@ -778,7 +779,7 @@ static void __init viper_tpm_init(void)
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0.sda_pin =3D V=
IPER_TPM_I2C_SDA_GPIO,
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0.scl_pin =3D V=
IPER_TPM_I2C_SCL_GPIO,
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0.udelay =C2=A0=
=3D 10,
> - =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 .timeout =3D 100,
> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 .timeout =3D HZ / =
10,
> =C2=A0 =C2=A0 =C2=A0 =C2=A0};
> =C2=A0 =C2=A0 =C2=A0 =C2=A0char *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 thi=
s
to jiffies using msec_to_jiffies() at run-time.