linux-kernel - [PATCH v4 4/6] tty: serial: amba-pl011: replace TIOCMBIT macros by static functions

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Message-Id: <20231123-mbly-uart-v4-4-7f913a74ff89@bootlin.com>
Date:   Thu, 23 Nov 2023 14:42:42 +0100
From:   Théo Lebrun <theo.lebrun@...tlin.com>
To:     Russell King <linux@...linux.org.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Grégory Clement <gregory.clement@...tlin.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>,
        Tawfik Bayouk <tawfik.bayouk@...ileye.com>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        Théo Lebrun <theo.lebrun@...tlin.com>
Subject: [PATCH v4 4/6] tty: serial: amba-pl011: replace TIOCMBIT macros by
 static functions

The driver uses two TIOCMBIT macros inside pl011_{get,set}_mctrl to
simplify the logic. Those look scary to checkpatch because they contain
ifs without do-while loops.

Avoid the macros by creating small equivalent static functions; that
lets the compiler do its type checking & avoids checkpatch errors.

For the second instance __assign_bit is not usable because it deals with
unsigned long pointers whereas we have an unsigned int in
pl011_set_mctrl.

Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
---
 drivers/tty/serial/amba-pl011.c | 45 ++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 3beac358909f..cf9aefe2fd28 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1594,6 +1594,12 @@ static unsigned int pl011_tx_empty(struct uart_port *port)
 							0 : TIOCSER_TEMT;
 }
 
+static void pl011_maybe_set_bit(bool cond, unsigned int *ptr, unsigned int mask)
+{
+	if (cond)
+		*ptr |= mask;
+}
+
 static unsigned int pl011_get_mctrl(struct uart_port *port)
 {
 	struct uart_amba_port *uap =
@@ -1601,18 +1607,22 @@ static unsigned int pl011_get_mctrl(struct uart_port *port)
 	unsigned int result = 0;
 	unsigned int status = pl011_read(uap, REG_FR);
 
-#define TIOCMBIT(uartbit, tiocmbit)	\
-	if (status & uartbit)		\
-		result |= tiocmbit
+	pl011_maybe_set_bit(status & UART01x_FR_DCD, &result, TIOCM_CAR);
+	pl011_maybe_set_bit(status & uap->vendor->fr_dsr, &result, TIOCM_DSR);
+	pl011_maybe_set_bit(status & uap->vendor->fr_cts, &result, TIOCM_CTS);
+	pl011_maybe_set_bit(status & uap->vendor->fr_ri, &result, TIOCM_RNG);
 
-	TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
-	TIOCMBIT(uap->vendor->fr_dsr, TIOCM_DSR);
-	TIOCMBIT(uap->vendor->fr_cts, TIOCM_CTS);
-	TIOCMBIT(uap->vendor->fr_ri, TIOCM_RNG);
-#undef TIOCMBIT
 	return result;
 }
 
+static void pl011_assign_bit(bool cond, unsigned int *ptr, unsigned int mask)
+{
+	if (cond)
+		*ptr |= mask;
+	else
+		*ptr &= ~mask;
+}
+
 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	struct uart_amba_port *uap =
@@ -1621,23 +1631,16 @@ static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
 
 	cr = pl011_read(uap, REG_CR);
 
-#define	TIOCMBIT(tiocmbit, uartbit)		\
-	if (mctrl & tiocmbit)		\
-		cr |= uartbit;		\
-	else				\
-		cr &= ~uartbit
-
-	TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
-	TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
-	TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
-	TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
-	TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
+	pl011_assign_bit(mctrl & TIOCM_RTS, &cr, UART011_CR_RTS);
+	pl011_assign_bit(mctrl & TIOCM_DTR, &cr, UART011_CR_DTR);
+	pl011_assign_bit(mctrl & TIOCM_OUT1, &cr, UART011_CR_OUT1);
+	pl011_assign_bit(mctrl & TIOCM_OUT2, &cr, UART011_CR_OUT2);
+	pl011_assign_bit(mctrl & TIOCM_LOOP, &cr, UART011_CR_LBE);
 
 	if (port->status & UPSTAT_AUTORTS) {
 		/* We need to disable auto-RTS if we want to turn RTS off */
-		TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
+		pl011_assign_bit(mctrl & TIOCM_RTS, &cr, UART011_CR_RTSEN);
 	}
-#undef TIOCMBIT
 
 	pl011_write(cr, uap, REG_CR);
 }

-- 
2.42.0