netdev - [net-next 12/14] ptp: stmac: convert to .adjfine and adjust_by_scaled

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Message-Id: <20220818222742.1070935-13-jacob.e.keller@intel.com>
Date:   Thu, 18 Aug 2022 15:27:40 -0700
From:   Jacob Keller <jacob.e.keller@...el.com>
To:     netdev@...r.kernel.org
Cc:     Jacob Keller <jacob.e.keller@...el.com>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Siva Reddy Kallam <siva.kallam@...adcom.com>,
        Prashant Sreedharan <prashant@...adcom.com>,
        Michael Chan <mchan@...adcom.com>,
        Yisen Zhuang <yisen.zhuang@...wei.com>,
        Salil Mehta <salil.mehta@...wei.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Tony Nguyen <anthony.l.nguyen@...el.com>,
        Tariq Toukan <tariqt@...dia.com>,
        Saeed Mahameed <saeedm@...dia.com>,
        Leon Romanovsky <leon@...nel.org>,
        Bryan Whitehead <bryan.whitehead@...rochip.com>,
        Sergey Shtylyov <s.shtylyov@....ru>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Richard Cochran <richardcochran@...il.com>,
        Vivek Thampi <vithampi@...are.com>,
        VMware PV-Drivers Reviewers <pv-drivers@...are.com>,
        Jie Wang <wangjie125@...wei.com>,
        Guangbin Huang <huangguangbin2@...wei.com>,
        Eran Ben Elisha <eranbe@...dia.com>,
        Aya Levin <ayal@...dia.com>,
        Cai Huoqing <cai.huoqing@...ux.dev>,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Phil Edworthy <phil.edworthy@...esas.com>,
        Jiasheng Jiang <jiasheng@...as.ac.cn>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Wan Jiabing <wanjiabing@...o.com>,
        Lv Ruyi <lv.ruyi@....com.cn>, Arnd Bergmann <arnd@...db.de>
Subject: [net-next 12/14] ptp: stmac: convert to .adjfine and adjust_by_scaled_ppm

The stmac implementation of .adjfreq is implemented in terms of a
straight forward "base * ppb / 1 billion" calculation.

Convert this driver to .adjfine and use the adjust_by_scaled_ppm helper
function to perform the calculation of the new addend.

Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@...com>
Cc: Alexandre Torgue <alexandre.torgue@...s.st.com>
Cc: Jose Abreu <joabreu@...opsys.com>
---

I do not have this hardware, and have only compile tested the change.

 .../net/ethernet/stmicro/stmmac/stmmac_ptp.c  | 23 ++++++-------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 4d11980dcd64..0d5e6819ee5d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -15,29 +15,20 @@
  * stmmac_adjust_freq
  *
  * @ptp: pointer to ptp_clock_info structure
- * @ppb: desired period change in parts ber billion
+ * @scaled_ppm: desired period change in scaled parts per million
  *
  * Description: this function will adjust the frequency of hardware clock.
+ *
+ * Scaled parts per million is ppm with a 16-bit binary fractional field.
  */
-static int stmmac_adjust_freq(struct ptp_clock_info *ptp, s32 ppb)
+static int stmmac_adjust_freq(struct ptp_clock_info *ptp, long scaled_ppm)
 {
 	struct stmmac_priv *priv =
 	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
 	unsigned long flags;
-	u32 diff, addend;
-	int neg_adj = 0;
-	u64 adj;
+	u32 addend;
 
-	if (ppb < 0) {
-		neg_adj = 1;
-		ppb = -ppb;
-	}
-
-	addend = priv->default_addend;
-	adj = addend;
-	adj *= ppb;
-	diff = div_u64(adj, 1000000000ULL);
-	addend = neg_adj ? (addend - diff) : (addend + diff);
+	addend = (u32)adjust_by_scaled_ppm(priv->default_addend, scaled_ppm);
 
 	write_lock_irqsave(&priv->ptp_lock, flags);
 	stmmac_config_addend(priv, priv->ptpaddr, addend);
@@ -269,7 +260,7 @@ static struct ptp_clock_info stmmac_ptp_clock_ops = {
 	.n_per_out = 0, /* will be overwritten in stmmac_ptp_register */
 	.n_pins = 0,
 	.pps = 0,
-	.adjfreq = stmmac_adjust_freq,
+	.adjfine = stmmac_adjust_freq,
 	.adjtime = stmmac_adjust_time,
 	.gettime64 = stmmac_get_time,
 	.settime64 = stmmac_set_time,
-- 
2.37.1.208.ge72d93e88cb2