Here my rewritten patch for rs485 support for kernel 2.6.24.7
Read/write direction ot differential bus transceiver will be changed by /RTS
with output port register 0p0 and 0p1;
To switch uart to rs485 mode, a 1 has to be written to
/sys/dev/f00000000.soc5200/f0002x000.serial/uartmode.
*void private_data in struct uart_port will point t a variable for each port to
mark
mode.
A uart console can not be switched to rs485 mode
Maybe this is usefull for somebody
Criticism is welcome
cheers
diff -uprN linux-2.6.24.7-el392-rt11-can751_org/drivers/serial/Kconfig
linux-2.6.24.7-el392-rt11-can751/drivers/serial/Kconfig
--- linux-2.6.24.7-el392-rt11-can751_org/drivers/serial/Kconfig 2008-10-16
13:35:31.000000000 +0200
+++ linux-2.6.24.7-el392-rt11-can751/drivers/serial/Kconfig 2008-11-13
15:44:19.000000000 +0100
@@ -1123,6 +1123,13 @@ config SERIAL_MPC52xx
for use as console, it must be included in kernel and not as a
module.
+config SERIAL_RS485
+ bool "RS485 support"
+ depends on SERIAL_MPC52xx
+ help
+ This drivers support serial RS485 ports. If you like
+ to use them, answer Y to this option.
+
config SERIAL_MPC52xx_CONSOLE
bool "Console on a Freescale MPC52xx family PSC serial port"
depends on SERIAL_MPC52xx=y
diff -uprN linux-2.6.24.7-el392-rt11-can751_org/drivers/serial/mpc52xx_uart.c
linux-2.6.24.7-el392-rt11-can751/drivers/serial/mpc52xx_uart.c
--- linux-2.6.24.7-el392-rt11-can751_org/drivers/serial/mpc52xx_uart.c
2008-10-16 13:40:15.000000000 +0200
+++ linux-2.6.24.7-el392-rt11-can751/drivers/serial/mpc52xx_uart.c
2008-11-17 15:55:07.000000000 +0100
@@ -21,11 +21,25 @@
* Copyright (C) 2004-2006 Sylvain Munaut <[EMAIL PROTECTED]>
* Copyright (C) 2003 MontaVista, Software, Inc.
*
+ * RS485 support is written by Hans Lehmann
+ * <[EMAIL PROTECTED]>
+ *
* This file is licensed under the terms of the GNU General Public License
* version 2. This program is licensed "as is" without any warranty of any
* kind, whether express or implied.
*/
+/* RS485 Usage:
+ * The driver will autmaticly handle a uart port in RS485 mode if you set
uartmode
+ * in /sys/device/f00000000.soc5200/f0002x000.serial to 1
+ * "echo 1 > /sys/device/f00000000.soc5200/f0002x000.serial/uartmode
+ * We misuse void pointer private->data in struct uart_port
+ * to determinate handle of port.
+ * RTS bit is used to set direction of differential bus transceiver
+ * Set mpc52xx_psc_op1 asserts output port /RTS: Write
+ * Set mpc52xx_psc_op0 negate output port /RTS: Read
+*/
+
/* Platform device Usage :
*
* Since PSCs can have multiple function, the correct driver for each one
@@ -94,6 +108,12 @@
#define ISR_PASS_LIMIT 256 /* Max number of iteration in the interrupt */
+#define RS485_SET_RTS 0x01 /* for ouput port 1 bit
set */
+#define RS485_CLR_RTS RS485_SET_RTS /* for ouput port 0 bit
set */
+
+#define RS485 1
+#define RS232 0
+
static struct uart_port mpc52xx_uart_ports[MPC52xx_PSC_MAXNUM];
/* Rem: - We use the read_status_mask as a shadow of
@@ -132,6 +152,12 @@ static struct of_device_id mpc52xx_uart_
};
#endif
+/* Simple variable to set private->data
+ * private data will be used to test, how to handle port
+*/
+#ifdef CONFIG_SERIAL_RS485
+int uartmode = RS232;
+#endif /* CONFIG_SERIAL_RS485 */
/* ======================================================================== */
/* UART operations */
@@ -144,6 +170,20 @@ mpc52xx_uart_tx_empty(struct uart_port *
return (status & MPC52xx_PSC_SR_TXEMP) ? TIOCSER_TEMT : 0;
}
+#ifdef CONFIG_SERIAL_RS485
+static void
+mpc52xx_uart_rs485_rts_clear(struct uart_port *port)
+{
+ /* In RS485 mode negate output port /RTS after
+ * TX empty (underrun) IRQ, to be able to receive data, directly
+ */
+ out_8(&PSC(port)->mpc52xx_psc_op0, RS485_SET_RTS);
+ port->read_status_mask &= ~MPC52xx_PSC_IMR_TXEMP
+ & ~MPC52xx_PSC_IMR_TXRDY;
+ out_be16(&PSC(port)->mpc52xx_psc_imr,port->read_status_mask);
+}
+#endif /* CONFIG_SERIAL_RS485 */
+
static void
mpc52xx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
@@ -168,8 +208,18 @@ mpc52xx_uart_stop_tx(struct uart_port *p
static void
mpc52xx_uart_start_tx(struct uart_port *port)
{
- /* port->lock taken by caller */
- port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
+ /* port->lock taken by caller */
+#ifdef CONFIG_SERIAL_RS485
+ if (*(int *)port->private_data){
+ /* Set /RTS immidiate before start transaction
+ * Make sure tx empty interrupt is on
+ */
+ port->read_status_mask |= MPC52xx_PSC_IMR_TXEMP
+ | MPC52xx_PSC_IMR_TXRDY;
+ out_8(&PSC(port)->mpc52xx_psc_op1, RS485_CLR_RTS);
+ } else
+#endif /* CONFIG_SERIAL_RS485 */
+ port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
out_be16(&PSC(port)->mpc52xx_psc_imr,port->read_status_mask);
}
@@ -513,6 +563,14 @@ mpc52xx_uart_int_tx_chars(struct uart_po
{
struct circ_buf *xmit = &port->info->xmit;
+#ifdef CONFIG_SERIAL_RS485
+ /* Tx Empty in RS485 Mode */
+ if (uart_circ_empty(xmit) && mpc52xx_uart_tx_empty(port)){
+ mpc52xx_uart_rs485_rts_clear(port);
+ return 0;
+ }
+#endif /* CONFIG_SERIAL_RS485 */
+
/* Process out of band chars */
if (port->x_char) {
out_8(&PSC(port)->mpc52xx_psc_buffer_8, port->x_char);
@@ -578,6 +636,15 @@ mpc52xx_uart_int(int irq, void *dev_id)
if ( status & MPC52xx_PSC_IMR_TXRDY )
keepgoing |= mpc52xx_uart_int_tx_chars(port);
+#ifdef CONFIG_SERIAL_RS485
+ /* Do we need to send chars in RS485 mode ? */
+ /* For this, TX must be ready, TX and TX empty
+ * interrupt enabled
+ */
+ if ((*(int *)port->private_data) && (status &
MPC52xx_PSC_IMR_TXEMP))
+ keepgoing |= mpc52xx_uart_int_tx_chars(port);
+#endif /* CONFIG_SERIAL_RS485 */
+
/* Limit number of iteration */
if ( !(--pass) )
keepgoing = 0;
@@ -805,6 +872,44 @@ console_initcall(mpc52xx_console_init);
#define MPC52xx_PSC_CONSOLE NULL
#endif
+#ifdef CONFIG_SERIAL_RS485
+/* ======================================================================== */
+/* SYSFS operations */
+/* ======================================================================== */
+
+static ssize_t read_uartmode(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf)
+{
+ struct uart_port *port = (struct uart_port *) dev_get_drvdata(dev);
+
+ printk("Type ttyPSC%i: %i\n", port->line,*(int *)port->private_data);
+ return strlen(buf)+1;
+}
+
+static ssize_t write_uartmode(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct uart_port *port = (struct uart_port *) dev_get_drvdata(dev);
+
+ uartmode = simple_strtoul(buf, NULL, 0);
+
+ if (!uart_console(port)){
+ if (uartmode || *(int *)port->private_data)
+ *(int *)port->private_data = uartmode;
+ printk("Type ttyPSC%i: %i\n", port->line,
+ *(int *)port->private_data);
+ } else
+ printk("ttyPSC%i is console\n",port->line);
+
+ uartmode = RS232;
+
+ return strlen (buf) + 1;
+}
+
+static DEVICE_ATTR(uartmode, S_IRUGO|S_IWUGO, read_uartmode, write_uartmode);
+#endif /* CONFIG_SERIAL_RS485 */
/* ======================================================================== */
/* UART Driver */
@@ -969,6 +1074,19 @@ mpc52xx_uart_of_probe(struct of_device *
port->ops = &mpc52xx_uart_ops;
port->dev = &op->dev;
+ /* to change uart mode, we need a entry point */
+#ifdef CONFIG_SERIAL_RS485
+ device_create_file(&op->dev, &dev_attr_uartmode);
+
+ /* for each port we have to allocate a variable */
+ port->private_data = kmalloc(sizeof(int), GFP_USER);
+ if (!port->private_data)
+ return -ENOMEM;
+
+ *(int *)port->private_data = RS232;
+
+#endif /* CONFIG_SERIAL_RS485 */
+
/* Search for IRQ and mapbase */
if ((ret = of_address_to_resource(op->node, 0, &res)) != 0)
return ret;
@@ -997,6 +1115,13 @@ mpc52xx_uart_of_remove(struct of_device
{
struct uart_port *port = dev_get_drvdata(&op->dev);
dev_set_drvdata(&op->dev, NULL);
+
+#ifdef CONFIG_SERIAL_RS485
+ device_remove_file(&op->dev, &dev_attr_uartmode);
+
+ /* Don't forget to free memory */
+ kfree(port->private_data);
+#endif /* CONFIG_SERIAL_RS485 */
if (port) {
uart_remove_one_port(&mpc52xx_uart_driver, port);
@@ -1132,6 +1257,7 @@ mpc52xx_uart_init(void)
return ret;
}
#else
+
ret = platform_driver_register(&mpc52xx_uart_platform_driver);
if (ret) {
printk(KERN_ERR "%s: platform_driver_register failed (%i)\n",
diff -uprN
linux-2.6.24.7-el392-rt11-can751_org/include/asm-powerpc/mpc52xx_psc.h
linux-2.6.24.7-el392-rt11-can751/include/asm-powerpc/mpc52xx_psc.h
--- linux-2.6.24.7-el392-rt11-can751_org/include/asm-powerpc/mpc52xx_psc.h
2008-10-16 13:35:05.000000000 +0200
+++ linux-2.6.24.7-el392-rt11-can751/include/asm-powerpc/mpc52xx_psc.h
2008-11-14 11:40:56.000000000 +0100
@@ -27,6 +27,7 @@
/* Max number of PSCs */
#define MPC52xx_PSC_MAXNUM 6
+
/* Programmable Serial Controller (PSC) status register bits */
#define MPC52xx_PSC_SR_CDE 0x0080
#define MPC52xx_PSC_SR_RXRDY 0x0100
@@ -64,6 +65,7 @@
#define MPC52xx_PSC_IMR_TXRDY 0x0100
#define MPC52xx_PSC_IMR_RXRDY 0x0200
#define MPC52xx_PSC_IMR_DB 0x0400
+#define MPC52xx_PSC_IMR_TXEMP MPC52xx_PSC_SR_TXEMP
#define MPC52xx_PSC_IMR_IPC 0x8000
/* PSC input port change bit */
@@ -139,8 +141,10 @@ struct mpc52xx_psc {
u8 ip; /* PSC + 0x34 */
u8 reserved9[3];
u8 op1; /* PSC + 0x38 */
+#define mpc52xx_psc_op1 op1
u8 reserved10[3];
u8 op0; /* PSC + 0x3c */
+#define mpc52xx_psc_op0 op0
u8 reserved11[3];
u32 sicr; /* PSC + 0x40 */
u8 ircr1; /* PSC + 0x44 */
Mit freundlichen Grüßen
Hans Lehmann
Softwareentwicklung
Telefon +49 (0)2191-67-2520
Fax +49 (0)2191-67-703408
e-mail [EMAIL PROTECTED]
Ritter Elektronik GmbH
Leverkuser Straße 65
D-42897 Remscheid
www.ritter-elektronik.de
Geschäftsführer: Manfred A. Wagner, Dr. Uwe Baader
Sitz der Gesellschaft: Oberhausen
HRB 17168 Duisburg / USt-ID DE 814009849
-----Ursprüngliche Nachricht-----
Von: Wolfram Sang [mailto:[EMAIL PROTECTED]
Gesendet: Donnerstag, 13. November 2008 19:42
An: Lehmann, Hans (Ritter Elektronik)
Cc: linuxppc-dev@ozlabs.org; Grant Likely
Betreff: Re: [PATCH v1] RS485 support for MPC5200x_psc_uart
Hello Hans,
On Thu, Nov 13, 2008 at 04:48:30PM +0100, Lehmann, Hans (Ritter Elektronik)
wrote:
> Adds rs485 support for MPC52xx_psc_uart
Please be more specific. What exactly was done/modified to have RS485-support.
Please also read SubmittingPatches and CodingStyle in the Documentation
directory and adapt your patch accordingly. For example: Send patches inlined,
this makes reviewing a lot easier. Don't use magic numbers. Use spaces around
operators. All this helps maintaining your code in the future.
> COM1 is console and not selectable.
COM1 is rarely selectable in Linux ;)
Kind regards,
Wolfram
--
Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de Pengutronix - Linux
Solutions for Science and Industry
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