Re: [PATCH net-next v2 3/7] net: phy: introduce phy_read_mmd_poll_timeout macro

[Andrew Lunn]

On Fri, Mar 20, 2020 at 09:34:27PM +0800, Dejin Zheng wrote:
> it is sometimes necessary to poll a phy register by phy_read_mmd()
> function until its value satisfies some condition. introduce
> phy_read_mmd_poll_timeout() macros that do this.
> 
> Suggested-by: Andrew Lunn <andrew@xxxxxxx>
> Signed-off-by: Dejin Zheng <zhengdejin5@xxxxxxxxx>
> ---
> v1 -> v2:
> 	- passed a phydev, device address and a reg to replace args...
> 	  parameter in phy_read_mmd_poll_timeout() by Andrew Lunn 's
> 	  suggestion. Andrew Lunn <andrew@xxxxxxx>, Thanks very much for
> 	  your help!
> 	- handle phy_read_mmd return an error(the return value < 0) in
> 	  phy_read_mmd_poll_timeout(). Thanks Andrew again.
> 
>  include/linux/phy.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 36d9dea04016..bb351f8b8769 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -24,6 +24,7 @@
>  #include <linux/mod_devicetable.h>
>  #include <linux/u64_stats_sync.h>
>  #include <linux/irqreturn.h>
> +#include <linux/iopoll.h>
>  
>  #include <linux/atomic.h>
>  
> @@ -784,6 +785,19 @@ static inline int __phy_modify_changed(struct phy_device *phydev, u32 regnum,
>   */
>  int phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum);
>  
> +#define phy_read_mmd_poll_timeout(val, cond, sleep_us, timeout_us, \
> +				  phydev, devad, regnum) \
> +({ \
> +	int ret = 0; \
> +	ret = read_poll_timeout(phy_read_mmd, val, cond || val < 0, sleep_us, \
> +				timeout_us, phydev, devad, regnum); \

Hi Dejin

You probably should have ( ) here to deal with precedence issues.

(cond) || val < 0

       Andrew