Subject: Re: [PATCH 1/1] wireless: move ifs' in _rtl92c_store_pwrIndex_diffrate_offset into elseif statements

From: Jan Ceuleers <[email-masked]>
Date: Sun, 05 Feb 2012 09:12:38 +0100

On 01/30/2012 07:50 AM, Devendra.Naga wrote:
> From: "Devendra.Naga"<[email-masked]>
>
>          The regaddr is compared against different rates in each case and the powerlevels are set
>          accordingly. as this can match for the first if and we still check for other powerlevels too,
>          use else if ratherthan using if statements
> Signed-off-by: Devendra.Naga<[email-masked]>
If this is correct, and I'm not saying it is or isn't, would it not be 
clearer to turn this whole section into a switch statement? The cases 
that requiring fiddling with the bitmask would need to be dealt with in 
the default: case.

Why was it written as a series of if statements to begin with: can (or 
could) any of these if statements change the value of regaddr such that 
later ifs evaluate differently? From reading only the patch the answer 
seems to be "no", so that looks good.

Or what about turning this into a data-driven section? It looks like 
values of regaddr are being translated into offsets into 
rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt]. Can this be done with a lookup 
table?

> ---
>   drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c |   47 +++++++------------
>   1 files changed, 17 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> index 22e998d..cb11e5a 100644
> --- a/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> +++ b/drivers/net/wireless/rtlwifi/rtl8192c/phy_common.c
> @@ -260,106 +260,93 @@ void _rtl92c_store_pwrIndex_diffrate_offset(struct ieee80211_hw *hw,
>   			 "MCSTxPowerLevelOriginalOffset[%d][0] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][0]);
> -	}
> -	if (regaddr == RTXAGC_A_RATE54_24) {
> +	} else if (regaddr == RTXAGC_A_RATE54_24) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][1] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][1]);
> -	}
> -	if (regaddr == RTXAGC_A_CCK1_MCS32) {
> +	} else if (regaddr == RTXAGC_A_CCK1_MCS32) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][6] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][6]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&  bitmask == 0xffffff00) {
> +	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&
> +		bitmask == 0xffffff00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][7] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][7]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS03_MCS00) {
> +	} else if (regaddr == RTXAGC_A_MCS03_MCS00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][2] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][2]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS07_MCS04) {
> +	} else if (regaddr == RTXAGC_A_MCS07_MCS04) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][3] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][3]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS11_MCS08) {
> +	} else if (regaddr == RTXAGC_A_MCS11_MCS08) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][4] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][4]);
> -	}
> -	if (regaddr == RTXAGC_A_MCS15_MCS12) {
> +	} else if (regaddr == RTXAGC_A_MCS15_MCS12) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][5] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][5]);
> -	}
> -	if (regaddr == RTXAGC_B_RATE18_06) {
> +	} else if (regaddr == RTXAGC_B_RATE18_06) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][8] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][8]);
> -	}
> -	if (regaddr == RTXAGC_B_RATE54_24) {
> +	} else if (regaddr == RTXAGC_B_RATE54_24) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][9] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][9]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
> +	} else if (regaddr == RTXAGC_B_CCK1_55_MCS32) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][14] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][14]);
> -	}
> -	if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&  bitmask == 0x000000ff) {
> +	} else if (regaddr == RTXAGC_B_CCK11_A_CCK2_11&&
> +		bitmask == 0x000000ff) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][15] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][15]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS03_MCS00) {
> +	} else if (regaddr == RTXAGC_B_MCS03_MCS00) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][10] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][10]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS07_MCS04) {
> +	} else if (regaddr == RTXAGC_B_MCS07_MCS04) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][11] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][11]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS11_MCS08) {
> +	} else if (regaddr == RTXAGC_B_MCS11_MCS08) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][12] = 0x%x\n",
>   			 rtlphy->pwrgroup_cnt,
>   			 rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][12]);
> -	}
> -	if (regaddr == RTXAGC_B_MCS15_MCS12) {
> +	} else if (regaddr == RTXAGC_B_MCS15_MCS12) {
>   		rtlphy->MCS_TXPWR[rtlphy->pwrgroup_cnt][13] = data;
>   		RT_TRACE(rtlpriv, COMP_INIT, DBG_TRACE,
>   			 "MCSTxPowerLevelOriginalOffset[%d][13] = 0x%x\n",