serial: make uart_console_write->putchar()'s character an unsigned char

Currently, uart_console_write->putchar's second parameter (the
character) is of type int. It makes little sense, provided uart_console_write()
accepts the input string as "const char *s" and passes its content -- the
characters -- to putchar(). So switch the character's type to unsigned
char.

We don't use char as that is signed on some platforms. That would cause
troubles for drivers which (implicitly) cast the char to u16 when
writing to the device. Sign extension would happen in that case and the
value written would be completely different to the provided char. DZ is
an example of such a driver -- on MIPS, it uses u16 for dz_out in
dz_console_putchar().

Note we do the char -> uchar conversion implicitly in
uart_console_write(). Provided we do not change size of the data type,
sign extension does not happen there, so the problem is void.

This makes the types consistent and unified with the rest of the uart
layer, which uses unsigned char in most places already. One exception is
xmit_buf, but that is going to be converted later.

Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@orcam.me.uk>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Karol Gugala <kgugala@antmicro.com>
Cc: Mateusz Holenko <mholenko@antmicro.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Taichi Sugaya <sugaya.taichi@socionext.com>
Cc: Takao Orito <orito.takao@socionext.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com> [atmel_serial]
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Neil Armstrong <narmstrong@baylibre.com> # meson_serial
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

62 files changed, 77 insertions, 76 deletions

diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index 5ed19a9857ad..ad13532e92fe 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -434,7 +434,7 @@ static int goldfish_tty_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
-static void gf_early_console_putchar(struct uart_port *port, int ch)
+static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	__raw_writel(ch, port->membase);
 }
diff --git a/drivers/tty/hvc/hvc_dcc.c b/drivers/tty/hvc/hvc_dcc.c
index 8e0edb7d93fd..bd61f9372d83 100644
--- a/drivers/tty/hvc/hvc_dcc.c
+++ b/drivers/tty/hvc/hvc_dcc.c
@@ -15,7 +15,7 @@
 #define DCC_STATUS_RX		(1 << 30)
 #define DCC_STATUS_TX		(1 << 29)
 
-static void dcc_uart_console_putchar(struct uart_port *port, int ch)
+static void dcc_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (__dcc_getstatus() & DCC_STATUS_TX)
 		cpu_relax();
diff --git a/drivers/tty/serial/21285.c b/drivers/tty/serial/21285.c
index 09baef4ccc39..7520cc02fd4d 100644
--- a/drivers/tty/serial/21285.c
+++ b/drivers/tty/serial/21285.c
@@ -403,7 +403,7 @@ static void serial21285_setup_ports(void)
 }
 
 #ifdef CONFIG_SERIAL_21285_CONSOLE
-static void serial21285_console_putchar(struct uart_port *port, int ch)
+static void serial21285_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (*CSR_UARTFLG & 0x20)
 		barrier();
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index c171ce6db691..e52585064565 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -86,7 +86,7 @@ static void serial8250_early_out(struct uart_port *port, int offset, int value)
 
 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
 
-static void serial_putc(struct uart_port *port, int c)
+static void serial_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned int status;
 
diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
index 65402d05eff9..cff91aa03f29 100644
--- a/drivers/tty/serial/8250/8250_ingenic.c
+++ b/drivers/tty/serial/8250/8250_ingenic.c
@@ -52,7 +52,7 @@ static void early_out(struct uart_port *port, int offset, uint8_t value)
 	writel(value, port->membase + (offset << 2));
 }
 
-static void ingenic_early_console_putc(struct uart_port *port, int c)
+static void ingenic_early_console_putc(struct uart_port *port, unsigned char c)
 {
 	uint8_t lsr;
 
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 25b84d30e771..267026892264 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3305,7 +3305,7 @@ EXPORT_SYMBOL_GPL(serial8250_set_defaults);
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
-static void serial8250_console_putchar(struct uart_port *port, int ch)
+static void serial8250_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c
index 37bffe406b18..1c16345d0a1f 100644
--- a/drivers/tty/serial/altera_jtaguart.c
+++ b/drivers/tty/serial/altera_jtaguart.c
@@ -298,7 +298,7 @@ static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];
 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)
 
 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
-static void altera_jtaguart_console_putc(struct uart_port *port, int c)
+static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned long status;
 	unsigned long flags;
@@ -318,7 +318,7 @@ static void altera_jtaguart_console_putc(struct uart_port *port, int c)
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 #else
-static void altera_jtaguart_console_putc(struct uart_port *port, int c)
+static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned long flags;
 
diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index 64a352b40197..8b749ed557c6 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -438,7 +438,7 @@ static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
 
 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
 
-static void altera_uart_console_putc(struct uart_port *port, int c)
+static void altera_uart_console_putc(struct uart_port *port, unsigned char c)
 {
 	while (!(altera_uart_readl(port, ALTERA_UART_STATUS_REG) &
 		 ALTERA_UART_STATUS_TRDY_MSK))
diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c
index b73375214ac3..fae0b581ff42 100644
--- a/drivers/tty/serial/amba-pl010.c
+++ b/drivers/tty/serial/amba-pl010.c
@@ -551,7 +551,7 @@ static struct uart_amba_port *amba_ports[UART_NR];
 
 #ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
 
-static void pl010_console_putchar(struct uart_port *port, int ch)
+static void pl010_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	unsigned int status;
 
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index ba053a68529f..51ecb050ae40 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2255,7 +2255,7 @@ static struct uart_amba_port *amba_ports[UART_NR];
 
 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
 
-static void pl011_console_putchar(struct uart_port *port, int ch)
+static void pl011_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_amba_port *uap =
 	    container_of(port, struct uart_amba_port, port);
@@ -2471,7 +2471,7 @@ static struct console amba_console = {
 
 #define AMBA_CONSOLE	(&amba_console)
 
-static void qdf2400_e44_putc(struct uart_port *port, int c)
+static void qdf2400_e44_putc(struct uart_port *port, unsigned char c)
 {
 	while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
 		cpu_relax();
@@ -2487,7 +2487,7 @@ static void qdf2400_e44_early_write(struct console *con, const char *s, unsigned
 	uart_console_write(&dev->port, s, n, qdf2400_e44_putc);
 }
 
-static void pl011_putc(struct uart_port *port, int c)
+static void pl011_putc(struct uart_port *port, unsigned char c)
 {
 	while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
 		cpu_relax();
diff --git a/drivers/tty/serial/apbuart.c b/drivers/tty/serial/apbuart.c
index d8c937bdf3f9..9ef82d870ff2 100644
--- a/drivers/tty/serial/apbuart.c
+++ b/drivers/tty/serial/apbuart.c
@@ -413,7 +413,7 @@ static void apbuart_flush_fifo(struct uart_port *port)
 
 #ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
 
-static void apbuart_console_putchar(struct uart_port *port, int ch)
+static void apbuart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	unsigned int status;
 	do {
diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
index 8cabe50c4a33..6269dbf93546 100644
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -613,7 +613,7 @@ static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
 	} while ((status & AR933X_UART_DATA_TX_CSR) == 0);
 }
 
-static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
+static void ar933x_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct ar933x_uart_port *up =
 		container_of(port, struct ar933x_uart_port, port);
diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 596217d10d5c..2a09e92ef9ed 100644
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -508,7 +508,7 @@ static int arc_serial_console_setup(struct console *co, char *options)
 	return uart_set_options(port, co, baud, parity, bits, flow);
 }
 
-static void arc_serial_console_putchar(struct uart_port *port, int ch)
+static void arc_serial_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (!(UART_GET_STATUS(port) & TXEMPTY))
 		cpu_relax();
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 73d43919898d..3a45e4fc7993 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2541,7 +2541,7 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
 }
 
 #ifdef CONFIG_SERIAL_ATMEL_CONSOLE
-static void atmel_console_putchar(struct uart_port *port, int ch)
+static void atmel_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
 		cpu_relax();
diff --git a/drivers/tty/serial/bcm63xx_uart.c b/drivers/tty/serial/bcm63xx_uart.c
index 6471a54b616b..53b43174aa40 100644
--- a/drivers/tty/serial/bcm63xx_uart.c
+++ b/drivers/tty/serial/bcm63xx_uart.c
@@ -681,7 +681,7 @@ static void wait_for_xmitr(struct uart_port *port)
 /*
  * output given char
  */
-static void bcm_console_putchar(struct uart_port *port, int ch)
+static void bcm_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	wait_for_xmitr(port);
 	bcm_uart_writel(port, ch, UART_FIFO_REG);
diff --git a/drivers/tty/serial/clps711x.c b/drivers/tty/serial/clps711x.c
index 95abc6faa3d5..b9b66ad31a08 100644
--- a/drivers/tty/serial/clps711x.c
+++ b/drivers/tty/serial/clps711x.c
@@ -348,7 +348,7 @@ static const struct uart_ops uart_clps711x_ops = {
 };
 
 #ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
-static void uart_clps711x_console_putchar(struct uart_port *port, int ch)
+static void uart_clps711x_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct clps711x_port *s = dev_get_drvdata(port->dev);
 	u32 sysflg = 0;
diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c
index 13ac36e2da4f..6d70fea76bb3 100644
--- a/drivers/tty/serial/digicolor-usart.c
+++ b/drivers/tty/serial/digicolor-usart.c
@@ -381,7 +381,7 @@ static const struct uart_ops digicolor_uart_ops = {
 	.request_port	= digicolor_uart_request_port,
 };
 
-static void digicolor_uart_console_putchar(struct uart_port *port, int ch)
+static void digicolor_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (digicolor_uart_tx_full(port))
 		cpu_relax();
diff --git a/drivers/tty/serial/dz.c b/drivers/tty/serial/dz.c
index e9edabc5a211..2e21acf39720 100644
--- a/drivers/tty/serial/dz.c
+++ b/drivers/tty/serial/dz.c
@@ -802,7 +802,7 @@ static void __init dz_init_ports(void)
  * restored.  Welcome to the world of PDP-11!
  * -------------------------------------------------------------------
  */
-static void dz_console_putchar(struct uart_port *uport, int ch)
+static void dz_console_putchar(struct uart_port *uport, unsigned char ch)
 {
 	struct dz_port *dport = to_dport(uport);
 	unsigned long flags;
diff --git a/drivers/tty/serial/earlycon-arm-semihost.c b/drivers/tty/serial/earlycon-arm-semihost.c
index fa096c10b591..fcdec5f42376 100644
--- a/drivers/tty/serial/earlycon-arm-semihost.c
+++ b/drivers/tty/serial/earlycon-arm-semihost.c
@@ -21,7 +21,7 @@
 /*
  * Semihosting-based debug console
  */
-static void smh_putc(struct uart_port *port, int c)
+static void smh_putc(struct uart_port *port, unsigned char c)
 {
 #ifdef CONFIG_ARM64
 	asm volatile("mov  x1, %0\n"
diff --git a/drivers/tty/serial/earlycon-riscv-sbi.c b/drivers/tty/serial/earlycon-riscv-sbi.c
index ce81523c3113..27afb0b74ea7 100644
--- a/drivers/tty/serial/earlycon-riscv-sbi.c
+++ b/drivers/tty/serial/earlycon-riscv-sbi.c
@@ -10,7 +10,7 @@
 #include <linux/serial_core.h>
 #include <asm/sbi.h>
 
-static void sbi_putc(struct uart_port *port, int c)
+static void sbi_putc(struct uart_port *port, unsigned char c)
 {
 	sbi_console_putchar(c);
 }
diff --git a/drivers/tty/serial/fsl_linflexuart.c b/drivers/tty/serial/fsl_linflexuart.c
index e72cba085743..98bb0c315e13 100644
--- a/drivers/tty/serial/fsl_linflexuart.c
+++ b/drivers/tty/serial/fsl_linflexuart.c
@@ -553,7 +553,7 @@ static const struct uart_ops linflex_pops = {
 static struct uart_port *linflex_ports[UART_NR];
 
 #ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
-static void linflex_console_putchar(struct uart_port *port, int ch)
+static void linflex_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	unsigned long cr;
 
@@ -578,7 +578,7 @@ static void linflex_console_putchar(struct uart_port *port, int ch)
 	}
 }
 
-static void linflex_earlycon_putchar(struct uart_port *port, int ch)
+static void linflex_earlycon_putchar(struct uart_port *port, unsigned char ch)
 {
 	unsigned long flags;
 	char *ret;
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 7d90c5a530ee..87789872f400 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -2333,13 +2333,13 @@ static const struct uart_ops lpuart32_pops = {
 static struct lpuart_port *lpuart_ports[UART_NR];
 
 #ifdef CONFIG_SERIAL_FSL_LPUART_CONSOLE
-static void lpuart_console_putchar(struct uart_port *port, int ch)
+static void lpuart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	lpuart_wait_bit_set(port, UARTSR1, UARTSR1_TDRE);
 	writeb(ch, port->membase + UARTDR);
 }
 
-static void lpuart32_console_putchar(struct uart_port *port, int ch)
+static void lpuart32_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	lpuart32_wait_bit_set(port, UARTSTAT, UARTSTAT_TDRE);
 	lpuart32_write(port, ch, UARTDATA);
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 0b467ce8d737..fd38e6ed4fda 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1968,7 +1968,7 @@ static const struct uart_ops imx_uart_pops = {
 static struct imx_port *imx_uart_ports[UART_NR];
 
 #if IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE)
-static void imx_uart_console_putchar(struct uart_port *port, int ch)
+static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct imx_port *sport = (struct imx_port *)port;
 
diff --git a/drivers/tty/serial/imx_earlycon.c b/drivers/tty/serial/imx_earlycon.c
index 795606e1a22f..7aab38b2bd8c 100644
--- a/drivers/tty/serial/imx_earlycon.c
+++ b/drivers/tty/serial/imx_earlycon.c
@@ -16,7 +16,7 @@
 #define UTS_TXFULL (1<<4) /* TxFIFO full */
 #define IMX21_UTS 0xb4 /* UART Test Register on all other i.mx*/
 
-static void imx_uart_console_early_putchar(struct uart_port *port, int ch)
+static void imx_uart_console_early_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (readl_relaxed(port->membase + IMX21_UTS) & UTS_TXFULL)
 		cpu_relax();
diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c
index f4dc5fe4ba92..655e64b26852 100644
--- a/drivers/tty/serial/ip22zilog.c
+++ b/drivers/tty/serial/ip22zilog.c
@@ -990,7 +990,7 @@ static struct zilog_layout * __init get_zs(int chip)
 #define ZS_PUT_CHAR_MAX_DELAY	2000	/* 10 ms */
 
 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
-static void ip22zilog_put_char(struct uart_port *port, int ch)
+static void ip22zilog_put_char(struct uart_port *port, unsigned char ch)
 {
 	struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
 	int loops = ZS_PUT_CHAR_MAX_DELAY;
diff --git a/drivers/tty/serial/lantiq.c b/drivers/tty/serial/lantiq.c
index 3e324d3f0a6d..a3120c3347dd 100644
--- a/drivers/tty/serial/lantiq.c
+++ b/drivers/tty/serial/lantiq.c
@@ -598,7 +598,7 @@ static const struct uart_ops lqasc_pops = {
 
 #ifdef CONFIG_SERIAL_LANTIQ_CONSOLE
 static void
-lqasc_console_putchar(struct uart_port *port, int ch)
+lqasc_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	int fifofree;
 
diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
index 7f74bf7bdcff..328b50521f14 100644
--- a/drivers/tty/serial/liteuart.c
+++ b/drivers/tty/serial/liteuart.c
@@ -93,7 +93,7 @@ static void liteuart_timer(struct timer_list *t)
 	mod_timer(&uart->timer, jiffies + uart_poll_timeout(port));
 }
 
-static void liteuart_putchar(struct uart_port *port, int ch)
+static void liteuart_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (litex_read8(port->membase + OFF_TXFULL))
 		cpu_relax();
diff --git a/drivers/tty/serial/lpc32xx_hs.c b/drivers/tty/serial/lpc32xx_hs.c
index 54437a087aa0..93140cac1ca1 100644
--- a/drivers/tty/serial/lpc32xx_hs.c
+++ b/drivers/tty/serial/lpc32xx_hs.c
@@ -122,7 +122,7 @@ static void wait_for_xmit_ready(struct uart_port *port)
 	}
 }
 
-static void lpc32xx_hsuart_console_putchar(struct uart_port *port, int ch)
+static void lpc32xx_hsuart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	wait_for_xmit_ready(port);
 	writel((u32)ch, LPC32XX_HSUART_FIFO(port->membase));
diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
index 45e00d928253..2bf1c57e0981 100644
--- a/drivers/tty/serial/meson_uart.c
+++ b/drivers/tty/serial/meson_uart.c
@@ -513,7 +513,7 @@ static void meson_uart_enable_tx_engine(struct uart_port *port)
 	writel(val, port->membase + AML_UART_CONTROL);
 }
 
-static void meson_console_putchar(struct uart_port *port, int ch)
+static void meson_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	if (!port->membase)
 		return;
diff --git a/drivers/tty/serial/milbeaut_usio.c b/drivers/tty/serial/milbeaut_usio.c
index 8f2cab7f66ad..347088bb380e 100644
--- a/drivers/tty/serial/milbeaut_usio.c
+++ b/drivers/tty/serial/milbeaut_usio.c
@@ -400,7 +400,7 @@ static const struct uart_ops mlb_usio_ops = {
 
 #ifdef CONFIG_SERIAL_MILBEAUT_USIO_CONSOLE
 
-static void mlb_usio_console_putchar(struct uart_port *port, int c)
+static void mlb_usio_console_putchar(struct uart_port *port, unsigned char c)
 {
 	while (!(readb(port->membase + MLB_USIO_REG_SSR) & MLB_USIO_SSR_TDRE))
 		cpu_relax();
diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
index 587b42f754cb..5e9429dcc51f 100644
--- a/drivers/tty/serial/mps2-uart.c
+++ b/drivers/tty/serial/mps2-uart.c
@@ -432,7 +432,7 @@ static const struct uart_ops mps2_uart_pops = {
 static DEFINE_IDR(ports_idr);
 
 #ifdef CONFIG_SERIAL_MPS2_UART_CONSOLE
-static void mps2_uart_console_putchar(struct uart_port *port, int ch)
+static void mps2_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (mps2_uart_read8(port, UARTn_STATE) & UARTn_STATE_TX_FULL)
 		cpu_relax();
@@ -484,7 +484,7 @@ static struct console mps2_uart_console = {
 
 #define MPS2_SERIAL_CONSOLE (&mps2_uart_console)
 
-static void mps2_early_putchar(struct uart_port *port, int ch)
+static void mps2_early_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (readb(port->membase + UARTn_STATE) & UARTn_STATE_TX_FULL)
 		cpu_relax();
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 45976e2140d4..0429c2a54290 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -676,7 +676,7 @@ static const struct uart_ops mvebu_uart_ops = {
 
 #ifdef CONFIG_SERIAL_MVEBU_CONSOLE
 /* Early Console */
-static void mvebu_uart_putc(struct uart_port *port, int c)
+static void mvebu_uart_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned int st;
 
@@ -737,7 +737,7 @@ static void wait_for_xmite(struct uart_port *port)
 				  (val & STAT_TX_EMP), 1, 10000);
 }
 
-static void mvebu_uart_console_putchar(struct uart_port *port, int ch)
+static void mvebu_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	wait_for_xmitr(port);
 	writel(ch, port->membase + UART_TSH(port));
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index ac45f3386e97..1944daf8593a 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1305,7 +1305,7 @@ static const struct uart_ops mxs_auart_ops = {
 static struct mxs_auart_port *auart_port[MXS_AUART_PORTS];
 
 #ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
-static void mxs_auart_console_putchar(struct uart_port *port, int ch)
+static void mxs_auart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct mxs_auart_port *s = to_auart_port(port);
 	unsigned int to = 1000;
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index b4e060205e61..8d5ffa196097 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1180,7 +1180,7 @@ static void omap_serial_early_out(struct uart_port *port, int offset,
 	writew(value, port->membase + offset);
 }
 
-static void omap_serial_early_putc(struct uart_port *port, int c)
+static void omap_serial_early_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned int status;
 
@@ -1224,7 +1224,7 @@ static struct uart_omap_port *serial_omap_console_ports[OMAP_MAX_HSUART_PORTS];
 
 static struct uart_driver serial_omap_reg;
 
-static void serial_omap_console_putchar(struct uart_port *port, int ch)
+static void serial_omap_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_omap_port *up = to_uart_omap_port(port);
 
diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
index 91f1eb0058d7..5250bd7d390a 100644
--- a/drivers/tty/serial/owl-uart.c
+++ b/drivers/tty/serial/owl-uart.c
@@ -516,7 +516,7 @@ static const struct uart_ops owl_uart_ops = {
 
 #ifdef CONFIG_SERIAL_OWL_CONSOLE
 
-static void owl_console_putchar(struct uart_port *port, int ch)
+static void owl_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	if (!port->membase)
 		return;
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index f0351e6f0ef6..affe71f8b50c 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1600,7 +1600,7 @@ static const struct uart_ops pch_uart_ops = {
 
 #ifdef CONFIG_SERIAL_PCH_UART_CONSOLE
 
-static void pch_console_putchar(struct uart_port *port, int ch)
+static void pch_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct eg20t_port *priv =
 		container_of(port, struct eg20t_port, port);
diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c
index 0a12fb11e698..b7a3a1b959b1 100644
--- a/drivers/tty/serial/pic32_uart.c
+++ b/drivers/tty/serial/pic32_uart.c
@@ -691,7 +691,7 @@ static const struct uart_ops pic32_uart_ops = {
 
 #ifdef CONFIG_SERIAL_PIC32_CONSOLE
 /* output given char */
-static void pic32_console_putchar(struct uart_port *port, int ch)
+static void pic32_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct pic32_sport *sport = to_pic32_sport(port);
 
diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
index 5359236b32d6..5d97c201ad88 100644
--- a/drivers/tty/serial/pmac_zilog.c
+++ b/drivers/tty/serial/pmac_zilog.c
@@ -1944,7 +1944,7 @@ static void __exit exit_pmz(void)
 
 #ifdef CONFIG_SERIAL_PMACZILOG_CONSOLE
 
-static void pmz_console_putchar(struct uart_port *port, int ch)
+static void pmz_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_pmac_port *uap =
 		container_of(port, struct uart_pmac_port, port);
diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c
index b4987b417f19..e80ba8e10407 100644
--- a/drivers/tty/serial/pxa.c
+++ b/drivers/tty/serial/pxa.c
@@ -605,7 +605,7 @@ static void wait_for_xmitr(struct uart_pxa_port *up)
 	}
 }
 
-static void serial_pxa_console_putchar(struct uart_port *port, int ch)
+static void serial_pxa_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
 
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index aedc38893e6c..1543a6028856 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -397,7 +397,7 @@ static void qcom_geni_serial_poll_put_char(struct uart_port *uport,
 #endif
 
 #ifdef CONFIG_SERIAL_QCOM_GENI_CONSOLE
-static void qcom_geni_serial_wr_char(struct uart_port *uport, int ch)
+static void qcom_geni_serial_wr_char(struct uart_port *uport, unsigned char ch)
 {
 	struct qcom_geni_private_data *private_data = uport->private_data;
 
diff --git a/drivers/tty/serial/rda-uart.c b/drivers/tty/serial/rda-uart.c
index d550d8fa2fab..e5f1fded423a 100644
--- a/drivers/tty/serial/rda-uart.c
+++ b/drivers/tty/serial/rda-uart.c
@@ -573,7 +573,7 @@ static const struct uart_ops rda_uart_ops = {
 
 #ifdef CONFIG_SERIAL_RDA_CONSOLE
 
-static void rda_console_putchar(struct uart_port *port, int ch)
+static void rda_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	if (!port->membase)
 		return;
diff --git a/drivers/tty/serial/sa1100.c b/drivers/tty/serial/sa1100.c
index 697b6a002a16..5fe6cccfc1ae 100644
--- a/drivers/tty/serial/sa1100.c
+++ b/drivers/tty/serial/sa1100.c
@@ -695,7 +695,7 @@ void __init sa1100_register_uart(int idx, int port)
 
 
 #ifdef CONFIG_SERIAL_SA1100_CONSOLE
-static void sa1100_console_putchar(struct uart_port *port, int ch)
+static void sa1100_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct sa1100_port *sport =
 		container_of(port, struct sa1100_port, port);
diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index d002a4e48ed9..2bde7bde7116 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -2478,7 +2478,7 @@ static void s3c24xx_serial_put_poll_char(struct uart_port *port,
 #endif /* CONFIG_CONSOLE_POLL */
 
 static void
-s3c24xx_serial_console_putchar(struct uart_port *port, int ch)
+s3c24xx_serial_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	unsigned int ufcon = rd_regl(port, S3C2410_UFCON);
 
@@ -2965,7 +2965,7 @@ static void samsung_early_busyuart_fifo(struct uart_port *port)
 		;
 }
 
-static void samsung_early_putc(struct uart_port *port, int c)
+static void samsung_early_putc(struct uart_port *port, unsigned char c)
 {
 	if (readl(port->membase + S3C2410_UFCON) & S3C2410_UFCON_FIFOMODE)
 		samsung_early_busyuart_fifo(port);
diff --git a/drivers/tty/serial/sb1250-duart.c b/drivers/tty/serial/sb1250-duart.c
index 738df6d9c0d9..2cf8533ef760 100644
--- a/drivers/tty/serial/sb1250-duart.c
+++ b/drivers/tty/serial/sb1250-duart.c
@@ -820,7 +820,7 @@ static void __init sbd_probe_duarts(void)
  * console output.  The console_lock is held by the caller, so we
  * shouldn't be interrupted for more console activity.
  */
-static void sbd_console_putchar(struct uart_port *uport, int ch)
+static void sbd_console_putchar(struct uart_port *uport, unsigned char ch)
 {
 	struct sbd_port *sport = to_sport(uport);
 
diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
index 10cc16a71f26..c56de2e104d4 100644
--- a/drivers/tty/serial/sccnxp.c
+++ b/drivers/tty/serial/sccnxp.c
@@ -828,7 +828,7 @@ static const struct uart_ops sccnxp_ops = {
 };
 
 #ifdef CONFIG_SERIAL_SCCNXP_CONSOLE
-static void sccnxp_console_putchar(struct uart_port *port, int c)
+static void sccnxp_console_putchar(struct uart_port *port, unsigned char c)
 {
 	int tryes = 100000;
 
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 846192a7b4bf..a1688a341411 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1911,7 +1911,7 @@ static void uart_port_spin_lock_init(struct uart_port *port)
  */
 void uart_console_write(struct uart_port *port, const char *s,
 			unsigned int count,
-			void (*putchar)(struct uart_port *, int))
+			void (*putchar)(struct uart_port *, unsigned char))
 {
 	unsigned int i;
 
diff --git a/drivers/tty/serial/serial_txx9.c b/drivers/tty/serial/serial_txx9.c
index cd38cf1f03cb..a695e9c1a06a 100644
--- a/drivers/tty/serial/serial_txx9.c
+++ b/drivers/tty/serial/serial_txx9.c
@@ -876,7 +876,7 @@ static void __init serial_txx9_register_ports(struct uart_driver *drv,
 
 #ifdef CONFIG_SERIAL_TXX9_CONSOLE
 
-static void serial_txx9_console_putchar(struct uart_port *port, int ch)
+static void serial_txx9_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_txx9_port *up = to_uart_txx9_port(port);
 
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 77d76973858f..0f9b8bd23500 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2960,7 +2960,7 @@ static void sci_cleanup_single(struct sci_port *port)
 
 #if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || \
     defined(CONFIG_SERIAL_SH_SCI_EARLYCON)
-static void serial_console_putchar(struct uart_port *port, int ch)
+static void serial_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	sci_poll_put_char(port, ch);
 }
diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c
index b79900d0e91a..f5ac14c384c4 100644
--- a/drivers/tty/serial/sifive.c
+++ b/drivers/tty/serial/sifive.c
@@ -756,7 +756,7 @@ static void sifive_serial_poll_put_char(struct uart_port *port,
  */
 
 #ifdef CONFIG_SERIAL_EARLYCON
-static void early_sifive_serial_putc(struct uart_port *port, int c)
+static void early_sifive_serial_putc(struct uart_port *port, unsigned char c)
 {
 	while (__ssp_early_readl(port, SIFIVE_SERIAL_TXDATA_OFFS) &
 	       SIFIVE_SERIAL_TXDATA_FULL_MASK)
@@ -800,7 +800,7 @@ OF_EARLYCON_DECLARE(sifive, "sifive,fu540-c000-uart0",
 
 static struct sifive_serial_port *sifive_serial_console_ports[SIFIVE_SERIAL_MAX_PORTS];
 
-static void sifive_serial_console_putchar(struct uart_port *port, int ch)
+static void sifive_serial_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct sifive_serial_port *ssp = port_to_sifive_serial_port(port);
 
diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 9a7ae6384edf..4329b9c9cbf0 100644
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -984,7 +984,7 @@ static void wait_for_xmitr(struct uart_port *port)
 	} while (status & SPRD_TX_FIFO_CNT_MASK);
 }
 
-static void sprd_console_putchar(struct uart_port *port, int ch)
+static void sprd_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	wait_for_xmitr(port);
 	serial_out(port, SPRD_TXD, ch);
@@ -1058,7 +1058,7 @@ console_initcall(sprd_serial_console_init);
 #define SPRD_CONSOLE	(&sprd_console)
 
 /* Support for earlycon */
-static void sprd_putc(struct uart_port *port, int c)
+static void sprd_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned int timeout = SPRD_TIMEOUT;
 
diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 87e480cc8206..d7fd692286cf 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -854,7 +854,7 @@ static int asc_serial_resume(struct device *dev)
 /*----------------------------------------------------------------------*/
 
 #ifdef CONFIG_SERIAL_ST_ASC_CONSOLE
-static void asc_console_putchar(struct uart_port *port, int ch)
+static void asc_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	unsigned int timeout = 1000000;
 
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 1b3a611ac39e..87b5cd4c9743 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1641,7 +1641,7 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 }
 
 #ifdef CONFIG_SERIAL_STM32_CONSOLE
-static void stm32_usart_console_putchar(struct uart_port *port, int ch)
+static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
diff --git a/drivers/tty/serial/sunplus-uart.c b/drivers/tty/serial/sunplus-uart.c
index 1c7a30bf5f04..9f15922e681b 100644
--- a/drivers/tty/serial/sunplus-uart.c
+++ b/drivers/tty/serial/sunplus-uart.c
@@ -500,7 +500,8 @@ static const struct uart_ops sunplus_uart_ops = {
 #ifdef CONFIG_SERIAL_SUNPLUS_CONSOLE
 struct sunplus_uart_port *sunplus_console_ports[SUP_UART_NR];
 
-static void sunplus_uart_console_putchar(struct uart_port *port, int ch)
+static void sunplus_uart_console_putchar(struct uart_port *port,
+					 unsigned char ch)
 {
 	wait_for_xmitr(port);
 	sp_uart_put_char(port, ch);
@@ -736,7 +737,7 @@ static void __exit sunplus_uart_exit(void)
 module_exit(sunplus_uart_exit);
 
 #ifdef CONFIG_SERIAL_EARLYCON
-static void sunplus_uart_putc(struct uart_port *port, int c)
+static void sunplus_uart_putc(struct uart_port *port, unsigned char c)
 {
 	unsigned int val;
 	int ret;
diff --git a/drivers/tty/serial/sunsab.c b/drivers/tty/serial/sunsab.c
index 92e572634009..6ea52293d9f3 100644
--- a/drivers/tty/serial/sunsab.c
+++ b/drivers/tty/serial/sunsab.c
@@ -846,7 +846,7 @@ static struct uart_sunsab_port *sunsab_ports;
 
 #ifdef CONFIG_SERIAL_SUNSAB_CONSOLE
 
-static void sunsab_console_putchar(struct uart_port *port, int c)
+static void sunsab_console_putchar(struct uart_port *port, unsigned char c)
 {
 	struct uart_sunsab_port *up =
 		container_of(port, struct uart_sunsab_port, port);
diff --git a/drivers/tty/serial/sunsu.c b/drivers/tty/serial/sunsu.c
index 98b2f4fb9a99..c31389114b86 100644
--- a/drivers/tty/serial/sunsu.c
+++ b/drivers/tty/serial/sunsu.c
@@ -1281,7 +1281,7 @@ static void wait_for_xmitr(struct uart_sunsu_port *up)
 	}
 }
 
-static void sunsu_console_putchar(struct uart_port *port, int ch)
+static void sunsu_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct uart_sunsu_port *up =
 		container_of(port, struct uart_sunsu_port, port);
diff --git a/drivers/tty/serial/sunzilog.c b/drivers/tty/serial/sunzilog.c
index b714b00d2dad..c14275d83b0b 100644
--- a/drivers/tty/serial/sunzilog.c
+++ b/drivers/tty/serial/sunzilog.c
@@ -100,7 +100,7 @@ struct uart_sunzilog_port {
 #endif
 };
 
-static void sunzilog_putchar(struct uart_port *port, int ch);
+static void sunzilog_putchar(struct uart_port *port, unsigned char ch);
 
 #define ZILOG_CHANNEL_FROM_PORT(PORT)	((struct zilog_channel __iomem *)((PORT)->membase))
 #define UART_ZILOG(PORT)		((struct uart_sunzilog_port *)(PORT))
@@ -1125,7 +1125,7 @@ static void sunzilog_free_tables(void)
 
 #define ZS_PUT_CHAR_MAX_DELAY	2000	/* 10 ms */
 
-static void __maybe_unused sunzilog_putchar(struct uart_port *port, int ch)
+static void __maybe_unused sunzilog_putchar(struct uart_port *port, unsigned char ch)
 {
 	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
 	int loops = ZS_PUT_CHAR_MAX_DELAY;
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index e1fa52d31474..007db67292a2 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -482,7 +482,7 @@ static void ulite_console_wait_tx(struct uart_port *port)
 			 "timeout waiting for TX buffer empty\n");
 }
 
-static void ulite_console_putchar(struct uart_port *port, int ch)
+static void ulite_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	ulite_console_wait_tx(port);
 	uart_out32(ch, ULITE_TX, port);
@@ -558,7 +558,7 @@ static struct console ulite_console = {
 	.data	= &ulite_uart_driver,
 };
 
-static void early_uartlite_putc(struct uart_port *port, int c)
+static void early_uartlite_putc(struct uart_port *port, unsigned char c)
 {
 	/*
 	 * Limit how many times we'll spin waiting for TX FIFO status.
diff --git a/drivers/tty/serial/vr41xx_siu.c b/drivers/tty/serial/vr41xx_siu.c
index 8586a56d4deb..e0bf003ca3a1 100644
--- a/drivers/tty/serial/vr41xx_siu.c
+++ b/drivers/tty/serial/vr41xx_siu.c
@@ -730,7 +730,7 @@ static void wait_for_xmitr(struct uart_port *port)
 	}
 }
 
-static void siu_console_putchar(struct uart_port *port, int ch)
+static void siu_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	wait_for_xmitr(port);
 	siu_write(port, UART_TX, ch);
diff --git a/drivers/tty/serial/vt8500_serial.c b/drivers/tty/serial/vt8500_serial.c
index 9adfe3dc970f..6f08136ce78a 100644
--- a/drivers/tty/serial/vt8500_serial.c
+++ b/drivers/tty/serial/vt8500_serial.c
@@ -484,7 +484,7 @@ static void wait_for_xmitr(struct uart_port *port)
 	} while (status & 0x10);
 }
 
-static void vt8500_console_putchar(struct uart_port *port, int c)
+static void vt8500_console_putchar(struct uart_port *port, unsigned char c)
 {
 	wait_for_xmitr(port);
 	writeb(c, port->membase + VT8500_TXFIFO);
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index d5e243908d9f..250a1d888eeb 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1142,7 +1142,7 @@ static struct uart_driver cdns_uart_uart_driver;
  * @port: Handle to the uart port structure
  * @ch: Character to be written
  */
-static void cdns_uart_console_putchar(struct uart_port *port, int ch)
+static void cdns_uart_console_putchar(struct uart_port *port, unsigned char ch)
 {
 	while (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)
 		cpu_relax();
diff --git a/drivers/tty/serial/zs.c b/drivers/tty/serial/zs.c
index 4b4f604646a7..70969bf9d82c 100644
--- a/drivers/tty/serial/zs.c
+++ b/drivers/tty/serial/zs.c
@@ -1124,7 +1124,7 @@ static int __init zs_probe_sccs(void)
 
 
 #ifdef CONFIG_SERIAL_ZS_CONSOLE
-static void zs_console_putchar(struct uart_port *uport, int ch)
+static void zs_console_putchar(struct uart_port *uport, unsigned char ch)
 {
 	struct zs_port *zport = to_zport(uport);
 	struct zs_scc *scc = zport->scc;
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 31f7fe527395..14ae35f68abb 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -399,7 +399,7 @@ int uart_set_options(struct uart_port *port, struct console *co, int baud,
 struct tty_driver *uart_console_device(struct console *co, int *index);
 void uart_console_write(struct uart_port *port, const char *s,
 			unsigned int count,
-			void (*putchar)(struct uart_port *, int));
+			void (*putchar)(struct uart_port *, unsigned char));
 
 /*
  * Port/driver registration/removal