Commit 4ce193fd authored by Alexander Shiyan's avatar Alexander Shiyan Committed by Greg Kroah-Hartman
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serial: sccnxp: Adds a delay between sequential read/write cycles 



This patch adds a delay between sequential read/write cycles,
to ensure the required minimum inactive time (tRWD). A time value
from the datasheet has been added for each type of supported chips.
The “inline” compiler attribute has been removed from the
read/write functions, simply allow the compiler to control this.

Signed-off-by: default avatarAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 663abb1a

drivers/tty/serial/sccnxp.c

+27 −5
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#endif



#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>
@@ -103,6 +104,8 @@ struct sccnxp_chip { 
	unsigned long		freq_max;

	unsigned int		flags;

	unsigned int		fifosize;

	/* Time between read/write cycles */

	unsigned int		trwd;

};



struct sccnxp_port {
@@ -137,6 +140,7 @@ static const struct sccnxp_chip sc2681 = { 
	.freq_max	= 4000000,

	.flags		= SCCNXP_HAVE_IO,

	.fifosize	= 3,

	.trwd		= 200,

};



static const struct sccnxp_chip sc2691 = {
@@ -147,6 +151,7 @@ static const struct sccnxp_chip sc2691 = { 
	.freq_max	= 4000000,

	.flags		= 0,

	.fifosize	= 3,

	.trwd		= 150,

};



static const struct sccnxp_chip sc2692 = {
@@ -157,6 +162,7 @@ static const struct sccnxp_chip sc2692 = { 
	.freq_max	= 4000000,

	.flags		= SCCNXP_HAVE_IO,

	.fifosize	= 3,

	.trwd		= 30,

};



static const struct sccnxp_chip sc2891 = {
@@ -167,6 +173,7 @@ static const struct sccnxp_chip sc2891 = { 
	.freq_max	= 8000000,

	.flags		= SCCNXP_HAVE_IO | SCCNXP_HAVE_MR0,

	.fifosize	= 16,

	.trwd		= 27,

};



static const struct sccnxp_chip sc2892 = {
@@ -177,6 +184,7 @@ static const struct sccnxp_chip sc2892 = { 
	.freq_max	= 8000000,

	.flags		= SCCNXP_HAVE_IO | SCCNXP_HAVE_MR0,

	.fifosize	= 16,

	.trwd		= 17,

};



static const struct sccnxp_chip sc28202 = {
@@ -187,6 +195,7 @@ static const struct sccnxp_chip sc28202 = { 
	.freq_max	= 50000000,

	.flags		= SCCNXP_HAVE_IO | SCCNXP_HAVE_MR0,

	.fifosize	= 256,

	.trwd		= 10,

};



static const struct sccnxp_chip sc68681 = {
@@ -197,6 +206,7 @@ static const struct sccnxp_chip sc68681 = { 
	.freq_max	= 4000000,

	.flags		= SCCNXP_HAVE_IO,

	.fifosize	= 3,

	.trwd		= 200,

};



static const struct sccnxp_chip sc68692 = {
@@ -207,24 +217,36 @@ static const struct sccnxp_chip sc68692 = { 
	.freq_max	= 4000000,

	.flags		= SCCNXP_HAVE_IO,

	.fifosize	= 3,

	.trwd		= 200,

};



static inline u8 sccnxp_read(struct uart_port *port, u8 reg)

static u8 sccnxp_read(struct uart_port *port, u8 reg)

{

	return readb(port->membase + (reg << port->regshift));

	struct sccnxp_port *s = dev_get_drvdata(port->dev);

	u8 ret;



	ret = readb(port->membase + (reg << port->regshift));



	ndelay(s->chip->trwd);



	return ret;

}



static inline void sccnxp_write(struct uart_port *port, u8 reg, u8 v)

static void sccnxp_write(struct uart_port *port, u8 reg, u8 v)

{

	struct sccnxp_port *s = dev_get_drvdata(port->dev);



	writeb(v, port->membase + (reg << port->regshift));



	ndelay(s->chip->trwd);

}



static inline u8 sccnxp_port_read(struct uart_port *port, u8 reg)

static u8 sccnxp_port_read(struct uart_port *port, u8 reg)

{

	return sccnxp_read(port, (port->line << 3) + reg);

}



static inline void sccnxp_port_write(struct uart_port *port, u8 reg, u8 v)

static void sccnxp_port_write(struct uart_port *port, u8 reg, u8 v)

{

	sccnxp_write(port, (port->line << 3) + reg, v);

}

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