From: Guenter Roeck <linux@roeck-us.net>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-kernel@vger.kernel.org, Sudeep Holla <sudeep.holla@arm.com>,
Jean Delvare <jdelvare@suse.com>,
linux-arm-kernel@lists.infradead.org,
"open list:HARDWARE MONITORING" <linux-hwmon@vger.kernel.org>,
bcm-kernel-feedback-list@broadcom.com
Subject: Re: [PATCH v2 1/3] kernel: Provide a __pow10() function
Date: Tue, 7 May 2019 14:06:54 -0700 [thread overview]
Message-ID: <20190507210654.GA4951@roeck-us.net> (raw)
In-Reply-To: <20190507193504.28248-2-f.fainelli@gmail.com>
On Tue, May 07, 2019 at 12:35:02PM -0700, Florian Fainelli wrote:
> Provide a simple macro that can return the value of 10 raised to a
> positive integer. We are going to use this in order to scale units from
> firmware to HWMON.
>
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
> include/linux/kernel.h | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 2d14e21c16c0..62fc8bd84bc9 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -294,6 +294,17 @@ static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
> return (u32)(((u64) val * ep_ro) >> 32);
> }
>
> +/* Return in f the value of 10 raise to the power x */
> +#define __pow10(x, f)( \
> +{ \
> + typeof(x) __x = abs(x); \
> + f = 1; \
> + while (__x--) \
> + f *= 10; \
> + f; \
> +} \
> +)
Kind of unusual. I would have expected to use this like
f = __pow10(x);
ie without having to provide f as parameter. That would be much less
confusing. I assume this is to make the result type independent, but
I am not sure if that is worth the trouble.
Are there users outside the hwmon code ? If not, it might be simpler
to keep it there for now.
Thanks,
Guenter
> +
> #if defined(CONFIG_MMU) && \
> (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
> #define might_fault() __might_fault(__FILE__, __LINE__)
> --
> 2.17.1
>
next prev parent reply other threads:[~2019-05-07 21:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 19:35 [PATCH v2 0/3] hwmon: scmi: Scale values to target desired HWMON units Florian Fainelli
2019-05-07 19:35 ` [PATCH v2 1/3] kernel: Provide a __pow10() function Florian Fainelli
2019-05-07 21:06 ` Guenter Roeck [this message]
2019-05-07 21:49 ` Florian Fainelli
2019-05-07 23:21 ` Guenter Roeck
2019-05-07 19:35 ` [PATCH v2 2/3] firmware: arm_scmi: Fetch and store sensor scale Florian Fainelli
2019-05-07 19:35 ` [PATCH v2 3/3] hwmon: scmi: Scale values to target desired HWMON units Florian Fainelli
2019-05-07 21:14 ` Guenter Roeck
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