linux-kernel - [PATCH v3 2/5] i3c: master: svc: Replace bool rnw with union for HDR support

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Message-Id: <20250930-i3c_ddr-v3-2-b627dc2ef172@nxp.com>
Date: Tue, 30 Sep 2025 15:34:21 -0400
From: Frank Li <Frank.Li@....com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>, 
 Miquel Raynal <miquel.raynal@...tlin.com>, 
 Jonathan Cameron <jic23@...nel.org>, David Lechner <dlechner@...libre.com>, 
 Nuno Sá <nuno.sa@...log.com>, 
 Andy Shevchenko <andy@...nel.org>
Cc: linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 imx@...ts.linux.dev, linux-iio@...r.kernel.org, Frank Li <Frank.Li@....com>
Subject: [PATCH v3 2/5] i3c: master: svc: Replace bool rnw with union for
 HDR support

Replace the bool rnw field with a union in preparation for adding HDR
support. HDR uses a cmd field instead of the rnw bit to indicate read or
write direction.

Add helper function svc_cmd_is_read() to check transfer direction.

Add a local variable 'rnw' in svc_i3c_master_priv_xfers() to avoid
repeatedly accessing xfers[i].rnw.

No functional change.

Signed-off-by: Frank Li <Frank.Li@....com>
---
 drivers/i3c/master/svc-i3c-master.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 701ae165b25b7991360f3a862b34cc1870a9a2ba..956172dc9d5f1f54d76b4c2917f2d9cf3bd21a85 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -165,7 +165,11 @@
 
 struct svc_i3c_cmd {
 	u8 addr;
-	bool rnw;
+	union {
+		bool rnw;
+		u8 cmd;
+		u32 rnw_cmd;
+	};
 	u8 *in;
 	const void *out;
 	unsigned int len;
@@ -383,6 +387,11 @@ svc_i3c_master_dev_from_addr(struct svc_i3c_master *master,
 	return master->descs[i];
 }
 
+static bool svc_cmd_is_read(u32 rnw_cmd, u32 type)
+{
+	return rnw_cmd;
+}
+
 static void svc_i3c_master_emit_stop(struct svc_i3c_master *master)
 {
 	writel(SVC_I3C_MCTRL_REQUEST_STOP, master->regs + SVC_I3C_MCTRL);
@@ -1272,10 +1281,11 @@ static int svc_i3c_master_write(struct svc_i3c_master *master,
 }
 
 static int svc_i3c_master_xfer(struct svc_i3c_master *master,
-			       bool rnw, unsigned int xfer_type, u8 addr,
+			       u32 rnw_cmd, unsigned int xfer_type, u8 addr,
 			       u8 *in, const u8 *out, unsigned int xfer_len,
 			       unsigned int *actual_len, bool continued, bool repeat_start)
 {
+	bool rnw = svc_cmd_is_read(rnw_cmd, xfer_type);
 	int retry = repeat_start ? 1 : 2;
 	u32 reg;
 	int ret;
@@ -1463,7 +1473,7 @@ static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 	for (i = 0; i < xfer->ncmds; i++) {
 		struct svc_i3c_cmd *cmd = &xfer->cmds[i];
 
-		ret = svc_i3c_master_xfer(master, cmd->rnw, xfer->type,
+		ret = svc_i3c_master_xfer(master, cmd->rnw_cmd, xfer->type,
 					  cmd->addr, cmd->in, cmd->out,
 					  cmd->len, &cmd->actual_len,
 					  cmd->continued, i > 0);
@@ -1656,14 +1666,15 @@ static int svc_i3c_master_priv_xfers(struct i3c_dev_desc *dev,
 
 	for (i = 0; i < nxfers; i++) {
 		struct svc_i3c_cmd *cmd = &xfer->cmds[i];
+		bool rnw = xfers[i].rnw;
 
 		cmd->xfer = &xfers[i];
 		cmd->addr = master->addrs[data->index];
-		cmd->rnw = xfers[i].rnw;
-		cmd->in = xfers[i].rnw ? xfers[i].data.in : NULL;
-		cmd->out = xfers[i].rnw ? NULL : xfers[i].data.out;
+		cmd->rnw = rnw;
+		cmd->in = rnw ? xfers[i].data.in : NULL;
+		cmd->out = rnw ? NULL : xfers[i].data.out;
 		cmd->len = xfers[i].len;
-		cmd->actual_len = xfers[i].rnw ? xfers[i].len : 0;
+		cmd->actual_len = rnw ? xfers[i].len : 0;
 		cmd->continued = (i + 1) < nxfers;
 	}
 

-- 
2.34.1