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From: Claudiu Beznea <claudiu.beznea@kernel.org>
To: wsa+renesas@sang-engineering.com,
	tommaso.merciai.xr@bp.renesas.com, alexandre.belloni@bootlin.com,
	Frank.Li@nxp.com, p.zabel@pengutronix.de
Cc: claudiu.beznea@kernel.org, claudiu.beznea@tuxon.dev,
	linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Subject: [PATCH v3 13/17] i3c: renesas: Update HW registers after SW computations are done
Date: Mon,  8 Jun 2026 23:15:39 +0300	[thread overview]
Message-ID: <20260608201543.804902-14-claudiu.beznea@kernel.org> (raw)
In-Reply-To: <20260608201543.804902-1-claudiu.beznea@kernel.org>

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

renesas_i3c_bus_init() performs a number of computations and software
cache updates, interleaving them with hardware register writes. While
this works today, it makes it harder to minimize the time the controller
must remain powered when runtime PM is introduced.

Perform all software computations and cache updates first, then update
the hardware registers. This prepares for future runtime PM support.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v3:
- none

Changes in v2:
- collected tags

 drivers/i3c/master/renesas-i3c.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/i3c/master/renesas-i3c.c b/drivers/i3c/master/renesas-i3c.c
index dab643cd8859..38ce722881da 100644
--- a/drivers/i3c/master/renesas-i3c.c
+++ b/drivers/i3c/master/renesas-i3c.c
@@ -560,10 +560,6 @@ static int renesas_i3c_bus_init(struct i3c_master_controller *m)
 	if (!i3c->rate)
 		return -EINVAL;
 
-	ret = renesas_i3c_reset(i3c);
-	if (ret)
-		return ret;
-
 	i2c_total_ticks = DIV_ROUND_UP(i3c->rate, bus->scl_rate.i2c);
 	i3c_total_ticks = DIV_ROUND_UP(i3c->rate, bus->scl_rate.i3c);
 
@@ -614,27 +610,31 @@ static int renesas_i3c_bus_init(struct i3c_master_controller *m)
 			STDBR_SBRHO(double_SBR, od_high_ticks) |
 			STDBR_SBRLP(pp_low_ticks) |
 			STDBR_SBRHP(pp_high_ticks);
-	renesas_writel(i3c->regs, STDBR, i3c->i3c_STDBR);
 
 	/* Extended Bit Rate setting */
 	i3c->extbr = EXTBR_EBRLO(od_low_ticks) | EXTBR_EBRHO(od_high_ticks) |
 		     EXTBR_EBRLP(pp_low_ticks) | EXTBR_EBRHP(pp_high_ticks);
-	renesas_writel(i3c->regs, EXTBR, i3c->extbr);
-
-	renesas_writel(i3c->regs, REFCKCTL, REFCKCTL_IREFCKS(cks));
-	i3c->refclk_div = cks;
-
-	/* I3C hw init*/
-	renesas_i3c_hw_init(i3c);
 
 	ret = i3c_master_get_free_addr(m, 0);
 	if (ret < 0)
 		return ret;
 
+	info.dyn_addr = ret;
 	i3c->dyn_addr = ret;
-	renesas_writel(i3c->regs, MSDVAD, MSDVAD_MDYAD(ret) | MSDVAD_MDYADV);
+	i3c->refclk_div = cks;
+
+	ret = renesas_i3c_reset(i3c);
+	if (ret)
+		return ret;
+
+	renesas_writel(i3c->regs, STDBR, i3c->i3c_STDBR);
+	renesas_writel(i3c->regs, EXTBR, i3c->extbr);
+	renesas_writel(i3c->regs, REFCKCTL, REFCKCTL_IREFCKS(cks));
+	renesas_writel(i3c->regs, MSDVAD, MSDVAD_MDYAD(i3c->dyn_addr) | MSDVAD_MDYADV);
+
+	/* I3C hw init*/
+	renesas_i3c_hw_init(i3c);
 
-	info.dyn_addr = ret;
 	return i3c_master_set_info(&i3c->base, &info);
 }
 
-- 
2.43.0


  parent reply	other threads:[~2026-06-08 20:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-08 20:15 [PATCH v3 00/17] i3c: renesas: Suspend to RAM with power loss and runtime PM Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 01/17] i3c: renesas: Check that the transfer is valid before accessing it Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 02/17] i3c: renesas: Restore STDBR and EXTBR registers on resume Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 03/17] i3c: renesas: Follow the reset deassert order used in probe Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 04/17] i3c: renesas: Reconfigure the DATBAS register on re-attach Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 05/17] i3c: renesas: Reset the controller on resume Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 06/17] i3c: renesas: Perform Dynamic Address Assignment " Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 07/17] i3c: renesas: Do not attach devices if xfer failed Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 08/17] i3c: renesas: Clean DATBAS register on detach Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 09/17] i3c: renesas: Use reset_control_bulk_{assert, deassert}() Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 10/17] i3c: renesas: Return immediately if there is no transfer Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 11/17] i3c: renesas: Follow a unified pattern for transfer and command initialization Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 12/17] i3c: renesas: Drop the explicit memset() call Claudiu Beznea
2026-06-08 20:15 ` Claudiu Beznea [this message]
2026-06-08 20:15 ` [PATCH v3 14/17] i3c: renesas: Organize structures to avoid unnecessary padding Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 15/17] i3c: renesas: Use the "dev_name:irq_name" format for the interrupt name Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 16/17] i3c: renesas: Drop unnecessary tab Claudiu Beznea
2026-06-08 20:15 ` [PATCH v3 17/17] i3c: renesas: Add runtime PM support Claudiu Beznea

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