netdev - [PATCH net-next 3/7] net: stmmac: Precede entire addend calculation with its comment

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Message-Id: <20230824-stmmac-subsecond-inc-cleanup-v1-3-e0b9f7c18b37@redhat.com>
Date: Thu, 24 Aug 2023 13:32:54 -0500
From: Andrew Halaney <ahalaney@...hat.com>
To: Alexandre Torgue <alexandre.torgue@...s.st.com>, 
 Jose Abreu <joabreu@...opsys.com>, "David S. Miller" <davem@...emloft.net>, 
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, 
 Maxime Coquelin <mcoquelin.stm32@...il.com>, 
 Richard Cochran <richardcochran@...il.com>
Cc: netdev@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com, 
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 Andrew Halaney <ahalaney@...hat.com>
Subject: [PATCH net-next 3/7] net: stmmac: Precede entire addend
 calculation with its comment

The addend calculation is currently split. The variable to be programmed
is first altered, then a comment explaining the full calculation is
seen, then the variable is altered further before the calculation is
finished.

Make the comment the first thing read. This makes the conversion of
sub_second_increment from nanoseconds to hertz much easier to
understand and reads logically.

Signed-off-by: Andrew Halaney <ahalaney@...hat.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index ba38ca284e26..f0e585e6ef76 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -849,7 +849,6 @@ int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags)
 	stmmac_config_sub_second_increment(priv, priv->ptpaddr,
 					   priv->plat->clk_ptp_rate,
 					   xmac, &sub_second_inc);
-	temp = div_u64(NSEC_PER_SEC, sub_second_inc);

 	/* Store sub second increment for later use */
 	priv->sub_second_inc = sub_second_inc;
@@ -859,6 +858,7 @@ int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags)
 	 * addend = (2^32)/freq_div_ratio;
 	 * where, freq_div_ratio = 1e9ns/sub_second_inc
 	 */
+	temp = div_u64(NSEC_PER_SEC, sub_second_inc);
 	temp = (u64)(temp << 32);
 	priv->default_addend = div_u64(temp, priv->plat->clk_ptp_rate);
 	stmmac_config_addend(priv, priv->ptpaddr, priv->default_addend);

-- 
2.41.0