netdev - [net-next 06/14] ptp: tg3: convert to .adjfine and diff_by_scaled

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Date:   Thu, 18 Aug 2022 15:27:34 -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 06/14] ptp: tg3: convert to .adjfine and diff_by_scaled_ppm

The tg3 implementation of .adjfreq is implemented in terms of a
straight forward "base * ppb / 1 billion" calculation.

Convert this driver to the .adjfine implementation, and use
diff_by_scaled_ppm to calculate the correction value.

Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Cc: Siva Reddy Kallam <siva.kallam@...adcom.com>
Cc: Prashant Sreedharan <prashant@...adcom.com>
Cc: Michael Chan <mchan@...adcom.com>
---

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

 drivers/net/ethernet/broadcom/tg3.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index db1e9d810b41..c5dcbd83ae66 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -6179,27 +6179,23 @@ static int tg3_get_ts_info(struct net_device *dev, struct ethtool_ts_info *info)
 	return 0;
 }
 
-static int tg3_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+static int tg3_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 {
 	struct tg3 *tp = container_of(ptp, struct tg3, ptp_info);
-	bool neg_adj = false;
-	u32 correction = 0;
-
-	if (ppb < 0) {
-		neg_adj = true;
-		ppb = -ppb;
-	}
+	u32 correction;
+	bool neg_adj;
+	u64 diff;
 
 	/* Frequency adjustment is performed using hardware with a 24 bit
 	 * accumulator and a programmable correction value. On each clk, the
 	 * correction value gets added to the accumulator and when it
 	 * overflows, the time counter is incremented/decremented.
 	 *
-	 * So conversion from ppb to correction value is
-	 *		ppb * (1 << 24) / 1000000000
+	 * So conversion from scaled_ppm to correction value is
+	 *		(1 << 24) * scaled_ppm / (1000000 << 16)
 	 */
-	correction = div_u64((u64)ppb * (1 << 24), 1000000000ULL) &
-		     TG3_EAV_REF_CLK_CORRECT_MASK;
+	neg_adj = diff_by_scaled_ppm(1 << 24, scaled_ppm, &diff);
+	correction = diff & TG3_EAV_REF_CLK_CORRECT_MASK;
 
 	tg3_full_lock(tp, 0);
 
@@ -6330,7 +6326,7 @@ static const struct ptp_clock_info tg3_ptp_caps = {
 	.n_per_out	= 1,
 	.n_pins		= 0,
 	.pps		= 0,
-	.adjfreq	= tg3_ptp_adjfreq,
+	.adjfine	= tg3_ptp_adjfine,
 	.adjtime	= tg3_ptp_adjtime,
 	.gettimex64	= tg3_ptp_gettimex,
 	.settime64	= tg3_ptp_settime,
-- 
2.37.1.208.ge72d93e88cb2