atmel_serial: Atmel RS485 support
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From: Ryan Mallon on 21 Mar 2010 16:20 Claudio Scordino wrote: > Hi all, > > this is a patch to add RS485 support to the atmel_serial driver. > > The patch has been successfully tested by Sebastian Heutling (CC:-ed). > > Feedback (comments, suggestions, further testing) is welcome. > > Many thanks, > > Claudio > Please post patches inline in the message body as it makes them easier to reply to. Some comments below: > atmel_serial: RS485 support Signed-off-by: Claudio Scordino > <claudio(a)evidence.eu.com> Signed-off-by: Michael Trimarchi > <michael(a)evidence.eu.com> Signed-off-by: Rick Bronson <rick(a)efn.org> > Signed-off-by: Sebastian Heutling <Sebastian.Heutling(a)who-ing.de> --- > arch/arm/include/asm/ioctls.h | 2 + > arch/arm/mach-at91/include/mach/board.h | 4 + > drivers/serial/atmel_serial.c | 247 ++++++++++++++++++++++++++----- 3 > files changed, 218 insertions(+), 35 deletions(-) diff --git > a/arch/arm/include/asm/ioctls.h b/arch/arm/include/asm/ioctls.h index > a91d8a1..82f2177 100644 --- a/arch/arm/include/asm/ioctls.h +++ > b/arch/arm/include/asm/ioctls.h @@ -70,6 +70,8 @@ #define TIOCGICOUNT > 0x545D /* read serial port inline interrupt counts */ #define FIOQSIZE > 0x545E +#define TIOCSRS485 0x5461 + /* Used for packet mode */ #define > TIOCPKT_DATA 0 #define TIOCPKT_FLUSHREAD 1 diff --git > a/arch/arm/mach-at91/include/mach/board.h > b/arch/arm/mach-at91/include/mach/board.h index ceaec6c..21f1308 > 100644 --- a/arch/arm/mach-at91/include/mach/board.h +++ > b/arch/arm/mach-at91/include/mach/board.h @@ -39,6 +39,7 @@ #include > <linux/usb/atmel_usba_udc.h> #include <linux/atmel-mci.h> #include > <sound/atmel-ac97c.h> +#include <linux/serial.h> /* USB Device */ > struct at91_udc_data { @@ -146,6 +147,9 @@ struct atmel_uart_data { > short use_dma_tx; /* use transmit DMA? */ short use_dma_rx; /* use > receive DMA? */ void __iomem *regs; /* virtual base address, if any */ > + struct serial_rs485 rs485; /* this flag specifies + if the uart must > be used + as RS485 */ This comment is misleading, it is a struct not a flag. The comment should say that it is the rs485 settings for the uart. > }; extern void __init at91_add_device_serial(void); diff --git > a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c index > 2c9bf9b..21bf3a8 100644 --- a/drivers/serial/atmel_serial.c +++ > b/drivers/serial/atmel_serial.c @@ -38,6 +38,7 @@ #include > <linux/dma-mapping.h> #include <linux/atmel_pdc.h> #include > <linux/atmel_serial.h> +#include <linux/uaccess.h> #include <asm/io.h> > @@ -59,6 +60,9 @@ #include <linux/serial_core.h> +static void > atmel_start_rx(struct uart_port *port); +static void > atmel_stop_rx(struct uart_port *port); Can you move these functions, so that these declarations are not needed? > #ifdef CONFIG_SERIAL_ATMEL_TTYAT /* Use device name ttyAT, major 204 > and minor 154-169. This is necessary if we @@ -93,6 +97,7 @@ #define > UART_GET_BRGR(port) __raw_readl((port)->membase + ATMEL_US_BRGR) > #define UART_PUT_BRGR(port,v) __raw_writel(v, (port)->membase + > ATMEL_US_BRGR) #define UART_PUT_RTOR(port,v) __raw_writel(v, > (port)->membase + ATMEL_US_RTOR) +#define UART_PUT_TTGR(port, v) > __raw_writel(v, (port)->membase + ATMEL_US_TTGR) /* PDC registers */ > #define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + > ATMEL_PDC_PTCR) @@ -147,6 +152,16 @@ struct atmel_uart_port { unsigned > int irq_status_prev; struct circ_buf rx_ring; + + struct serial_rs485 > rs485; /* this flag specifies + if the uart must be used + as RS485 */ Same here. > + /* Fields related to interrupts: + if (rs485) = ATMEL_US_TXEMPTY + > else if (use_dma_tx) = ATMEL_US_ENDTX | ATMEL_US_TXBUFE + else = > ATMEL_US_TXRDY; + */ This comment doesn't really belong here. Also, please use *s as the beginning of each line in a multi-line comment. > + unsigned int tx_done_mask; }; static struct atmel_uart_port > atmel_ports[ATMEL_MAX_UART]; @@ -187,6 +202,85 @@ static bool > atmel_use_dma_tx(struct uart_port *port) } #endif +/* Enable or > disable the rs485 support */ +void atmel_enable_disable_rs485(struct > uart_port *port, struct serial_rs485 *rs485conf) Please change the name of this function, something like atmel_config_rs485 would be better. > +{ + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + > unsigned long flags; + unsigned int mode; + + > spin_lock_irqsave(&port->lock, flags); + + mode = UART_GET_MR(port); + > + /* Resetting serial mode to RS232 (0x0) */ + mode &= > ~ATMEL_US_USMODE; + + atmel_port->rs485 = *rs485conf; + + if > (!(rs485conf->flags & SER_RS485_ENABLED)) { Reversing the logic of this if statement will make it slightly easier to read. > + dev_dbg(port->dev, "Setting UART to RS232\n"); + if > (atmel_use_dma_tx(port)) + atmel_port->tx_done_mask = ATMEL_US_ENDTX | > ATMEL_US_TXBUFE; + else + atmel_port->tx_done_mask = ATMEL_US_TXRDY; + > } else { + dev_dbg(port->dev, "Setting UART to RS485\n"); + > atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; + UART_PUT_TTGR(port, > rs485conf->delay_rts_before_send); + mode |= ATMEL_US_USMODE_RS485; + > } + UART_PUT_MR(port, mode); + + spin_unlock_irqrestore(&port->lock, > flags); +} + + +static ssize_t show_rs485(struct device *dev, struct > device_attribute *attr, \ + char *buf) +{ + struct platform_device > *pdev = to_platform_device(dev); + struct uart_port *port = > platform_get_drvdata(pdev); + unsigned int current_mode; + + > current_mode = UART_GET_MR(port); + current_mode &= ATMEL_US_USMODE; current_mode = UART_GET_MR(port) & ATMEL_US_USMODE; > + return snprintf(buf, PAGE_SIZE, "%u\n", current_mode); +} + +static > ssize_t set_rs485(struct device *dev, struct device_attribute *attr, \ > + const char *buf, size_t len) +{ + struct platform_device *pdev = > to_platform_device(dev); + struct uart_port *port = > platform_get_drvdata(pdev); + struct atmel_uart_port *atmel_port = > to_atmel_uart_port(port); + struct serial_rs485 rs485conf = > atmel_port->rs485; + unsigned int value; + + if (buf == NULL) + goto err; if (!buf) goto -EINVAL; > + + value = simple_strtoul(buf, NULL, 10); + + if ((value != 0) && > (value != 1)) + goto err; Is there any reason to be so strict on the values, you could just do this: value = !!(simple_strtoul(buf, NULL, 0)); which will allow the user to use values in any base, and will convert any non-zero values to 1. > + if (!value) { + rs485conf.flags &= ~(SER_RS485_ENABLED); Again, I would revert the logic of this if statement. > + } else { + rs485conf.flags |= SER_RS485_ENABLED; + /* 0x4 is the > normal reset value. */ + rs485conf.delay_rts_before_send = 0x00000004; > + } + + atmel_enable_disable_rs485(port, &rs485conf); + +err: + return > strnlen(buf, PAGE_SIZE); +} + +static DEVICE_ATTR(rs485, 0644, > show_rs485, set_rs485); + /* * Return TIOCSER_TEMT when transmitter > FIFO and Shift register is empty. */ @@ -202,6 +296,7 @@ static void > atmel_set_mctrl(struct uart_port *port, u_int mctrl) { unsigned int > control = 0; unsigned int mode; + struct atmel_uart_port *atmel_port = > to_atmel_uart_port(port); #ifdef CONFIG_ARCH_AT91RM9200 if > (cpu_is_at91rm9200()) { @@ -236,6 +331,16 @@ static void > atmel_set_mctrl(struct uart_port *port, u_int mctrl) mode |= > ATMEL_US_CHMODE_LOC_LOOP; else mode |= ATMEL_US_CHMODE_NORMAL; + + /* > Resetting serial mode to RS232 (0x0) */ + mode &= ~ATMEL_US_USMODE; + > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) { + > dev_dbg(port->dev, "Keeping UART to RS485\n"); + UART_PUT_TTGR(port, > atmel_port->rs485.delay_rts_before_send); + mode |= > ATMEL_US_USMODE_RS485; + } else + dev_dbg(port->dev, "Keeping UART to > RS232\n"); UART_PUT_MR(port, mode); } @@ -268,12 +373,17 @@ static > u_int atmel_get_mctrl(struct uart_port *port) */ static void > atmel_stop_tx(struct uart_port *port) { + struct atmel_uart_port > *atmel_port = to_atmel_uart_port(port); + if (atmel_use_dma_tx(port)) > { /* disable PDC transmit */ UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS); - > UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); - } else - > UART_PUT_IDR(port, ATMEL_US_TXRDY); + } + /* Disable interrupts */ + > UART_PUT_IDR(port, atmel_port->tx_done_mask); + + if > (atmel_port->rs485.flags & SER_RS485_ENABLED) + atmel_start_rx(port); > } /* @@ -281,17 +391,22 @@ static void atmel_stop_tx(struct uart_port > *port) */ static void atmel_start_tx(struct uart_port *port) { + > struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + if > (atmel_use_dma_tx(port)) { if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN) > /* The transmitter is already running. Yes, we really need this.*/ > return; - UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); + if > (atmel_port->rs485.flags & SER_RS485_ENABLED) + atmel_stop_rx(port); + > /* re-enable PDC transmit */ UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); - } > else - UART_PUT_IER(port, ATMEL_US_TXRDY); + } + /* Enable interrupts > */ + UART_PUT_IER(port, atmel_port->tx_done_mask); } /* @@ -302,12 > +417,28 @@ static void atmel_stop_rx(struct uart_port *port) if > (atmel_use_dma_rx(port)) { /* disable PDC receive */ > UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS); - UART_PUT_IDR(port, > ATMEL_US_ENDRX | ATMEL_US_TIMEOUT); + UART_PUT_IDR(port, > ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | port->read_status_mask); This line, and a couple of others extend over 80 characters, can you please reformat, ie: UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | port->read_status_mask); > } else UART_PUT_IDR(port, ATMEL_US_RXRDY); Please use braces even on single line else statements in the case where the if statement has braces. > } /* + * start receiving - port is in process of being opened. + */ > +static void atmel_start_rx(struct uart_port *port) +{ + > UART_PUT_CR(port, ATMEL_US_RSTSTA); /* reset status and receiver */ + > + if (atmel_use_dma_rx(port)) { + /* enable PDC controller */ + > UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | > port->read_status_mask); + UART_PUT_PTCR(port, ATMEL_PDC_RXTEN); + } > else + UART_PUT_IER(port, ATMEL_US_RXRDY); +} + + +/* * Enable modem > status interrupts */ static void atmel_enable_ms(struct uart_port > *port) @@ -428,8 +559,9 @@ static void atmel_rx_chars(struct uart_port > *port) static void atmel_tx_chars(struct uart_port *port) { struct > circ_buf *xmit = &port->state->xmit; + struct atmel_uart_port > *atmel_port = to_atmel_uart_port(port); - if (port->x_char && > UART_GET_CSR(port) & ATMEL_US_TXRDY) { + if (port->x_char && > UART_GET_CSR(port) & atmel_port->tx_done_mask) { UART_PUT_CHAR(port, > port->x_char); port->icount.tx++; port->x_char = 0; @@ -437,7 +569,7 > @@ static void atmel_tx_chars(struct uart_port *port) if > (uart_circ_empty(xmit) || uart_tx_stopped(port)) return; - while > (UART_GET_CSR(port) & ATMEL_US_TXRDY) { + while (UART_GET_CSR(port) & > atmel_port->tx_done_mask) { UART_PUT_CHAR(port, > xmit->buf[xmit->tail]); xmit->tail = (xmit->tail + 1) & > (UART_XMIT_SIZE - 1); port->icount.tx++; @@ -449,7 +581,8 @@ static > void atmel_tx_chars(struct uart_port *port) uart_write_wakeup(port); > if (!uart_circ_empty(xmit)) - UART_PUT_IER(port, ATMEL_US_TXRDY); + /* > Enable interrupts */ + UART_PUT_IER(port, atmel_port->tx_done_mask); } > /* @@ -501,18 +634,10 @@ atmel_handle_transmit(struct uart_port *port, > unsigned int pending) { struct atmel_uart_port *atmel_port = > to_atmel_uart_port(port); - if (atmel_use_dma_tx(port)) { - /* PDC > transmit */ - if (pending & (ATMEL_US_ENDTX | ATMEL_US_TXBUFE)) { - > UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); - > tasklet_schedule(&atmel_port->tasklet); - } - } else { - /* Interrupt > transmit */ - if (pending & ATMEL_US_TXRDY) { - UART_PUT_IDR(port, > ATMEL_US_TXRDY); - tasklet_schedule(&atmel_port->tasklet); - } + if > (pending & atmel_port->tx_done_mask) { + /* Either PDC or interrupt > transmission */ + UART_PUT_IDR(port, atmel_port->tx_done_mask); + > tasklet_schedule(&atmel_port->tasklet); } } @@ -590,9 +715,15 @@ > static void atmel_tx_dma(struct uart_port *port) UART_PUT_TPR(port, > pdc->dma_addr + xmit->tail); UART_PUT_TCR(port, count); - /* re-enable > PDC transmit and interrupts */ + /* re-enable PDC transmit */ > UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); - UART_PUT_IER(port, > ATMEL_US_ENDTX | ATMEL_US_TXBUFE); + /* Enable interrupts */ + > UART_PUT_IER(port, atmel_port->tx_done_mask); + } else { + if > (atmel_port->rs485.flags & SER_RS485_ENABLED) { + /* DMA done, stop > TX, start RX for RS485 */ + atmel_start_rx(port); + } } if > (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) @@ -1017,6 +1148,7 @@ > static void atmel_set_termios(struct uart_port *port, struct ktermios > *termios, { unsigned long flags; unsigned int mode, imr, quot, baud; + > struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); /* Get > current mode register */ mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS > | ATMEL_US_CHRL @@ -1115,6 +1247,16 @@ static void > atmel_set_termios(struct uart_port *port, struct ktermios *termios, /* > disable receiver and transmitter */ UART_PUT_CR(port, ATMEL_US_TXDIS | > ATMEL_US_RXDIS); + /* Resetting serial mode to RS232 (0x0) */ + mode > &= ~ATMEL_US_USMODE; + + if (atmel_port->rs485.flags & > SER_RS485_ENABLED) { + dev_dbg(port->dev, "Keeping UART to RS485\n"); > + UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send); + mode > |= ATMEL_US_USMODE_RS485; + } else + dev_dbg(port->dev, "Keeping UART > to RS232\n"); + /* set the parity, stop bits and data size */ > UART_PUT_MR(port, mode); @@ -1231,6 +1373,31 @@ static void > atmel_poll_put_char(struct uart_port *port, unsigned char ch) } #endif > +static int atmel_ioctl(struct uart_port *port, unsigned int cmd, > unsigned long arg) +{ + + switch (cmd) { + case TIOCSRS485: + { + > struct serial_rs485 rs485conf; Moving this declaration to the top of the function will remove two indentation levels. Is it necessary to have both an ioctl and a sysfs control for putting the uart into rs485 mode? The ioctl is more standardised, so perhaps drop the sysfs control? > + if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg, + > sizeof(rs485conf))) + return -EFAULT; + + dev_dbg(port->dev, "enable > e/o disable rs485\n"); + + atmel_enable_disable_rs485(port, > &rs485conf); + } + break; + + default: + return -ENOIOCTLCMD; + } + > return 0; +} + + + static struct uart_ops atmel_pops = { .tx_empty = > atmel_tx_empty, .set_mctrl = atmel_set_mctrl, @@ -1250,6 +1417,7 @@ > static struct uart_ops atmel_pops = { .config_port = > atmel_config_port, .verify_port = atmel_verify_port, .pm = > atmel_serial_pm, + .ioctl = atmel_ioctl, #ifdef CONFIG_CONSOLE_POLL > .poll_get_char = atmel_poll_get_char, .poll_put_char = > atmel_poll_put_char, @@ -1265,13 +1433,12 @@ static void __devinit > atmel_init_port(struct atmel_uart_port *atmel_port, struct uart_port > *port = &atmel_port->uart; struct atmel_uart_data *data = > pdev->dev.platform_data; - port->iotype = UPIO_MEM; - port->flags = > UPF_BOOT_AUTOCONF; - port->ops = &atmel_pops; - port->fifosize = 1; - > port->line = pdev->id; - port->dev = &pdev->dev; - + port->iotype = > UPIO_MEM; + port->flags = UPF_BOOT_AUTOCONF; + port->ops = > &atmel_pops; + port->fifosize = 1; + port->line = pdev->id; + > port->dev = &pdev->dev; port->mapbase = pdev->resource[0].start; > port->irq = pdev->resource[1].start; @@ -1299,8 +1466,15 @@ static > void __devinit atmel_init_port(struct atmel_uart_port *atmel_port, > atmel_port->use_dma_rx = data->use_dma_rx; atmel_port->use_dma_tx = > data->use_dma_tx; - if (atmel_use_dma_tx(port)) + atmel_port->rs485 = > data->rs485; + /* Use TXEMPTY for interrupt when rs485 else TXRDY or > ENDTX|TXBUFE */ + if (atmel_port->rs485.flags & SER_RS485_ENABLED) + > atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; + else if > (atmel_use_dma_tx(port)) { port->fifosize = PDC_BUFFER_SIZE; + > atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE; + } else > + atmel_port->tx_done_mask = ATMEL_US_TXRDY; } /* @@ -1334,6 +1508,7 > @@ static void atmel_console_putchar(struct uart_port *port, int ch) > static void atmel_console_write(struct console *co, const char *s, > u_int count) { struct uart_port *port = &atmel_ports[co->index].uart; > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > unsigned int status, imr; unsigned int pdc_tx; @@ -1341,7 +1516,7 @@ > static void atmel_console_write(struct console *co, const char *s, > u_int count) * First, save IMR and then disable interrupts */ imr = > UART_GET_IMR(port); - UART_PUT_IDR(port, ATMEL_US_RXRDY | > ATMEL_US_TXRDY); + UART_PUT_IDR(port, ATMEL_US_RXRDY | > atmel_port->tx_done_mask); /* Store PDC transmit status and disable it > */ pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN; @@ -1355,7 +1530,7 > @@ static void atmel_console_write(struct console *co, const char *s, > u_int count) */ do { status = UART_GET_CSR(port); - } while (!(status > & ATMEL_US_TXRDY)); + } while (!(status & atmel_port->tx_done_mask)); > /* Restore PDC transmit status */ if (pdc_tx) @@ -1587,7 +1762,7 @@ > static int __devinit atmel_serial_probe(struct platform_device *pdev) > device_init_wakeup(&pdev->dev, 1); platform_set_drvdata(pdev, port); - > return 0; + return device_create_file(&(pdev->dev), &dev_attr_rs485); > err_add_port: kfree(port->rx_ring.buf); @@ -1619,6 +1794,8 @@ static > int __devexit atmel_serial_remove(struct platform_device *pdev) > clk_put(atmel_port->clk); + device_remove_file(&(pdev->dev), > &dev_attr_rs485); + return ret; } -- 1.6.0.4 ~Ryan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ryan Mallon on 21 Mar 2010 18:00 Claudio Scordino wrote: > Hi all, > > this is a patch to add RS485 support to the atmel_serial driver. > > The patch has been successfully tested by Sebastian Heutling (CC:-ed). > > Feedback (comments, suggestions, further testing) is welcome. > > Many thanks, > Ugh, not sure what happened to my previous email. It looked fine in Thunderbird before I sent it. Hopefully this works a bit better: > atmel_serial: RS485 support > > Signed-off-by: Claudio Scordino <claudio(a)evidence.eu.com> > Signed-off-by: Michael Trimarchi <michael(a)evidence.eu.com> > Signed-off-by: Rick Bronson <rick(a)efn.org> > Signed-off-by: Sebastian Heutling <Sebastian.Heutling(a)who-ing.de> > --- > arch/arm/include/asm/ioctls.h | 2 + > arch/arm/mach-at91/include/mach/board.h | 4 + > drivers/serial/atmel_serial.c | 247 > ++++++++++++++++++++++++++----- > 3 files changed, 218 insertions(+), 35 deletions(-) > > diff --git a/arch/arm/include/asm/ioctls.h b/arch/arm/include/asm/ioctls.h > index a91d8a1..82f2177 100644 > --- a/arch/arm/include/asm/ioctls.h > +++ b/arch/arm/include/asm/ioctls.h > @@ -70,6 +70,8 @@ > #define TIOCGICOUNT 0x545D /* read serial port inline interrupt > counts */ > #define FIOQSIZE 0x545E > > +#define TIOCSRS485 0x5461 > + > /* Used for packet mode */ > #define TIOCPKT_DATA 0 > #define TIOCPKT_FLUSHREAD 1 > diff --git a/arch/arm/mach-at91/include/mach/board.h > b/arch/arm/mach-at91/include/mach/board.h > index ceaec6c..21f1308 100644 > --- a/arch/arm/mach-at91/include/mach/board.h > +++ b/arch/arm/mach-at91/include/mach/board.h > @@ -39,6 +39,7 @@ > #include <linux/usb/atmel_usba_udc.h> > #include <linux/atmel-mci.h> > #include <sound/atmel-ac97c.h> > +#include <linux/serial.h> > > /* USB Device */ > struct at91_udc_data { > @@ -146,6 +147,9 @@ struct atmel_uart_data { > short use_dma_tx; /* use transmit DMA? */ > short use_dma_rx; /* use receive DMA? */ > void __iomem *regs; /* virtual base address, if any */ > + struct serial_rs485 rs485; /* this flag specifies > + if the uart must be used > + as RS485 */ > }; This comment is misleading, it is a struct not a flag. The comment should say that it is the rs485 settings for the uart. > extern void __init at91_add_device_serial(void); > > diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c > index 2c9bf9b..21bf3a8 100644 > --- a/drivers/serial/atmel_serial.c > +++ b/drivers/serial/atmel_serial.c > @@ -38,6 +38,7 @@ > #include <linux/dma-mapping.h> > #include <linux/atmel_pdc.h> > #include <linux/atmel_serial.h> > +#include <linux/uaccess.h> > > #include <asm/io.h> > > @@ -59,6 +60,9 @@ > > #include <linux/serial_core.h> > > +static void atmel_start_rx(struct uart_port *port); > +static void atmel_stop_rx(struct uart_port *port); Can you move these functions, so that these declarations are not needed? > #ifdef CONFIG_SERIAL_ATMEL_TTYAT > > /* Use device name ttyAT, major 204 and minor 154-169. This is > necessary if we > @@ -93,6 +97,7 @@ > #define UART_GET_BRGR(port) __raw_readl((port)->membase + > ATMEL_US_BRGR) > #define UART_PUT_BRGR(port,v) __raw_writel(v, (port)->membase + > ATMEL_US_BRGR) > #define UART_PUT_RTOR(port,v) __raw_writel(v, (port)->membase + > ATMEL_US_RTOR) > +#define UART_PUT_TTGR(port, v) __raw_writel(v, (port)->membase + > ATMEL_US_TTGR) > > /* PDC registers */ > #define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + > ATMEL_PDC_PTCR) > @@ -147,6 +152,16 @@ struct atmel_uart_port { > unsigned int irq_status_prev; > > struct circ_buf rx_ring; > + > + struct serial_rs485 rs485; /* this flag specifies > + if the uart must be used > + as RS485 */ > + /* Fields related to interrupts: > + if (rs485) = ATMEL_US_TXEMPTY > + else if (use_dma_tx) = ATMEL_US_ENDTX | ATMEL_US_TXBUFE > + else = ATMEL_US_TXRDY; > + */ This comment doesn't really belong here. Also, please use *s at the beginning of each line in a multiline comment. > + unsigned int tx_done_mask; > }; > > static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART]; > @@ -187,6 +202,85 @@ static bool atmel_use_dma_tx(struct uart_port *port) > } > #endif > > +/* Enable or disable the rs485 support */ > +void atmel_enable_disable_rs485(struct uart_port *port, struct > serial_rs485 *rs485conf) > +{ Please change the name of this function. Something like atmel_config_rs485 would be better. > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > + unsigned long flags; > + unsigned int mode; > + > + spin_lock_irqsave(&port->lock, flags); > + > + mode = UART_GET_MR(port); > + > + /* Resetting serial mode to RS232 (0x0) */ > + mode &= ~ATMEL_US_USMODE; > + > + atmel_port->rs485 = *rs485conf; > + > + if (!(rs485conf->flags & SER_RS485_ENABLED)) { Reversing the logic of this if statement will make it slightly easier to read. > + dev_dbg(port->dev, "Setting UART to RS232\n"); > + if (atmel_use_dma_tx(port)) > + atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE; > + else > + atmel_port->tx_done_mask = ATMEL_US_TXRDY; > + } else { > + dev_dbg(port->dev, "Setting UART to RS485\n"); > + atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; > + UART_PUT_TTGR(port, rs485conf->delay_rts_before_send); > + mode |= ATMEL_US_USMODE_RS485; > + } > + UART_PUT_MR(port, mode); > + > + spin_unlock_irqrestore(&port->lock, flags); > +} > + > + > +static ssize_t show_rs485(struct device *dev, struct device_attribute > *attr, \ > + char *buf) > +{ > + struct platform_device *pdev = to_platform_device(dev); > + struct uart_port *port = platform_get_drvdata(pdev); > + unsigned int current_mode; > + > + current_mode = UART_GET_MR(port); > + current_mode &= ATMEL_US_USMODE; current_mode = UART_GET_MR(port) & ATMEL_US_USMODE; > + return snprintf(buf, PAGE_SIZE, "%u\n", current_mode); > +} > + > +static ssize_t set_rs485(struct device *dev, struct device_attribute > *attr, \ > + const char *buf, size_t len) > +{ > + struct platform_device *pdev = to_platform_device(dev); > + struct uart_port *port = platform_get_drvdata(pdev); > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > + struct serial_rs485 rs485conf = atmel_port->rs485; > + unsigned int value; > + > + if (buf == NULL) > + goto err; if (!buf) return -EINVAL; > + > + value = simple_strtoul(buf, NULL, 10); > + > + if ((value != 0) && (value != 1)) > + goto err; Is there any reason to be so strict on the values, you could just do this: value = !!(simple_strtoul(buf, NULL, 0)); which will allow the user to use values in any base, and will convert any non-zero values to 1. > + > + if (!value) { Again, I would revert the logic of this if statement. > + rs485conf.flags &= ~(SER_RS485_ENABLED); > + } else { > + rs485conf.flags |= SER_RS485_ENABLED; > + /* 0x4 is the normal reset value. */ > + rs485conf.delay_rts_before_send = 0x00000004; > + } > + > + atmel_enable_disable_rs485(port, &rs485conf); > + > +err: > + return strnlen(buf, PAGE_SIZE); > +} > + > +static DEVICE_ATTR(rs485, 0644, show_rs485, set_rs485); > + > /* > * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty. > */ > @@ -202,6 +296,7 @@ static void atmel_set_mctrl(struct uart_port > *port, u_int mctrl) > { > unsigned int control = 0; > unsigned int mode; > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > > #ifdef CONFIG_ARCH_AT91RM9200 > if (cpu_is_at91rm9200()) { > @@ -236,6 +331,16 @@ static void atmel_set_mctrl(struct uart_port > *port, u_int mctrl) > mode |= ATMEL_US_CHMODE_LOC_LOOP; > else > mode |= ATMEL_US_CHMODE_NORMAL; > + > + /* Resetting serial mode to RS232 (0x0) */ > + mode &= ~ATMEL_US_USMODE; > + > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) { > + dev_dbg(port->dev, "Keeping UART to RS485\n"); > + UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send); > + mode |= ATMEL_US_USMODE_RS485; > + } else > + dev_dbg(port->dev, "Keeping UART to RS232\n"); > UART_PUT_MR(port, mode); > } > > @@ -268,12 +373,17 @@ static u_int atmel_get_mctrl(struct uart_port *port) > */ > static void atmel_stop_tx(struct uart_port *port) > { > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > + > if (atmel_use_dma_tx(port)) { > /* disable PDC transmit */ > UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS); > - UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); > - } else > - UART_PUT_IDR(port, ATMEL_US_TXRDY); > + } > + /* Disable interrupts */ > + UART_PUT_IDR(port, atmel_port->tx_done_mask); > + > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) > + atmel_start_rx(port); > } > > /* > @@ -281,17 +391,22 @@ static void atmel_stop_tx(struct uart_port *port) > */ > static void atmel_start_tx(struct uart_port *port) > { > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > + > if (atmel_use_dma_tx(port)) { > if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN) > /* The transmitter is already running. Yes, we > really need this.*/ > return; > > - UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) > + atmel_stop_rx(port); > + > /* re-enable PDC transmit */ > UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); > - } else > - UART_PUT_IER(port, ATMEL_US_TXRDY); > + } > + /* Enable interrupts */ > + UART_PUT_IER(port, atmel_port->tx_done_mask); > } > > /* > @@ -302,12 +417,28 @@ static void atmel_stop_rx(struct uart_port *port) > if (atmel_use_dma_rx(port)) { > /* disable PDC receive */ > UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS); > - UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT); > + UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | > port->read_status_mask); This line, and a couple of others, extend over 80 characters. Could you please split them up. > } else > UART_PUT_IDR(port, ATMEL_US_RXRDY); Please use braces for single line else statements when the if clause has braces. > } > > /* > + * start receiving - port is in process of being opened. > + */ > +static void atmel_start_rx(struct uart_port *port) > +{ > + UART_PUT_CR(port, ATMEL_US_RSTSTA); /* reset status and receiver */ > + > + if (atmel_use_dma_rx(port)) { > + /* enable PDC controller */ > + UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | > port->read_status_mask); > + UART_PUT_PTCR(port, ATMEL_PDC_RXTEN); > + } else > + UART_PUT_IER(port, ATMEL_US_RXRDY); > +} > + > + > +/* > * Enable modem status interrupts > */ > static void atmel_enable_ms(struct uart_port *port) > @@ -428,8 +559,9 @@ static void atmel_rx_chars(struct uart_port *port) > static void atmel_tx_chars(struct uart_port *port) > { > struct circ_buf *xmit = &port->state->xmit; > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > > - if (port->x_char && UART_GET_CSR(port) & ATMEL_US_TXRDY) { > + if (port->x_char && UART_GET_CSR(port) & atmel_port->tx_done_mask) { > UART_PUT_CHAR(port, port->x_char); > port->icount.tx++; > port->x_char = 0; > @@ -437,7 +569,7 @@ static void atmel_tx_chars(struct uart_port *port) > if (uart_circ_empty(xmit) || uart_tx_stopped(port)) > return; > > - while (UART_GET_CSR(port) & ATMEL_US_TXRDY) { > + while (UART_GET_CSR(port) & atmel_port->tx_done_mask) { > UART_PUT_CHAR(port, xmit->buf[xmit->tail]); > xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); > port->icount.tx++; > @@ -449,7 +581,8 @@ static void atmel_tx_chars(struct uart_port *port) > uart_write_wakeup(port); > > if (!uart_circ_empty(xmit)) > - UART_PUT_IER(port, ATMEL_US_TXRDY); > + /* Enable interrupts */ > + UART_PUT_IER(port, atmel_port->tx_done_mask); > } > > /* > @@ -501,18 +634,10 @@ atmel_handle_transmit(struct uart_port *port, > unsigned int pending) > { > struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > > - if (atmel_use_dma_tx(port)) { > - /* PDC transmit */ > - if (pending & (ATMEL_US_ENDTX | ATMEL_US_TXBUFE)) { > - UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); > - tasklet_schedule(&atmel_port->tasklet); > - } > - } else { > - /* Interrupt transmit */ > - if (pending & ATMEL_US_TXRDY) { > - UART_PUT_IDR(port, ATMEL_US_TXRDY); > - tasklet_schedule(&atmel_port->tasklet); > - } > + if (pending & atmel_port->tx_done_mask) { > + /* Either PDC or interrupt transmission */ > + UART_PUT_IDR(port, atmel_port->tx_done_mask); > + tasklet_schedule(&atmel_port->tasklet); > } > } > > @@ -590,9 +715,15 @@ static void atmel_tx_dma(struct uart_port *port) > > UART_PUT_TPR(port, pdc->dma_addr + xmit->tail); > UART_PUT_TCR(port, count); > - /* re-enable PDC transmit and interrupts */ > + /* re-enable PDC transmit */ > UART_PUT_PTCR(port, ATMEL_PDC_TXTEN); > - UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE); > + /* Enable interrupts */ > + UART_PUT_IER(port, atmel_port->tx_done_mask); > + } else { > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) { > + /* DMA done, stop TX, start RX for RS485 */ > + atmel_start_rx(port); > + } > } > > if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) > @@ -1017,6 +1148,7 @@ static void atmel_set_termios(struct uart_port > *port, struct ktermios *termios, > { > unsigned long flags; > unsigned int mode, imr, quot, baud; > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > > /* Get current mode register */ > mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL > @@ -1115,6 +1247,16 @@ static void atmel_set_termios(struct uart_port > *port, struct ktermios *termios, > /* disable receiver and transmitter */ > UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS); > > + /* Resetting serial mode to RS232 (0x0) */ > + mode &= ~ATMEL_US_USMODE; > + > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) { > + dev_dbg(port->dev, "Keeping UART to RS485\n"); > + UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send); > + mode |= ATMEL_US_USMODE_RS485; > + } else > + dev_dbg(port->dev, "Keeping UART to RS232\n"); > + > /* set the parity, stop bits and data size */ > UART_PUT_MR(port, mode); > > @@ -1231,6 +1373,31 @@ static void atmel_poll_put_char(struct > uart_port *port, unsigned char ch) > } > #endif > > +static int atmel_ioctl(struct uart_port *port, unsigned int cmd, > unsigned long arg) > +{ > + > + switch (cmd) { > + case TIOCSRS485: > + { > + struct serial_rs485 rs485conf; If you move this declaration to the top of the function you will save two levels of indentation. Is it necessary to have both an ioctl and a sysfs control for putting the uart into rs485 mode? The ioctl is more standardised, so perhaps drop the sysfs control? > + if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg, > + sizeof(rs485conf))) > + return -EFAULT; > + > + dev_dbg(port->dev, "enable e/o disable rs485\n"); > + > + atmel_enable_disable_rs485(port, &rs485conf); > + } > + break; > + > + default: > + return -ENOIOCTLCMD; > + } > + return 0; > +} > + > + > + > static struct uart_ops atmel_pops = { > .tx_empty = atmel_tx_empty, > .set_mctrl = atmel_set_mctrl, > @@ -1250,6 +1417,7 @@ static struct uart_ops atmel_pops = { > .config_port = atmel_config_port, > .verify_port = atmel_verify_port, > .pm = atmel_serial_pm, > + .ioctl = atmel_ioctl, > #ifdef CONFIG_CONSOLE_POLL > .poll_get_char = atmel_poll_get_char, > .poll_put_char = atmel_poll_put_char, > @@ -1265,13 +1433,12 @@ static void __devinit atmel_init_port(struct > atmel_uart_port *atmel_port, > struct uart_port *port = &atmel_port->uart; > struct atmel_uart_data *data = pdev->dev.platform_data; > > - port->iotype = UPIO_MEM; > - port->flags = UPF_BOOT_AUTOCONF; > - port->ops = &atmel_pops; > - port->fifosize = 1; > - port->line = pdev->id; > - port->dev = &pdev->dev; > - > + port->iotype = UPIO_MEM; > + port->flags = UPF_BOOT_AUTOCONF; > + port->ops = &atmel_pops; > + port->fifosize = 1; > + port->line = pdev->id; > + port->dev = &pdev->dev; > port->mapbase = pdev->resource[0].start; > port->irq = pdev->resource[1].start; > > @@ -1299,8 +1466,15 @@ static void __devinit atmel_init_port(struct > atmel_uart_port *atmel_port, > > atmel_port->use_dma_rx = data->use_dma_rx; > atmel_port->use_dma_tx = data->use_dma_tx; > - if (atmel_use_dma_tx(port)) > + atmel_port->rs485 = data->rs485; > + /* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */ > + if (atmel_port->rs485.flags & SER_RS485_ENABLED) > + atmel_port->tx_done_mask = ATMEL_US_TXEMPTY; > + else if (atmel_use_dma_tx(port)) { > port->fifosize = PDC_BUFFER_SIZE; > + atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE; > + } else > + atmel_port->tx_done_mask = ATMEL_US_TXRDY; > } > > /* > @@ -1334,6 +1508,7 @@ static void atmel_console_putchar(struct > uart_port *port, int ch) > static void atmel_console_write(struct console *co, const char *s, > u_int count) > { > struct uart_port *port = &atmel_ports[co->index].uart; > + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > unsigned int status, imr; > unsigned int pdc_tx; > > @@ -1341,7 +1516,7 @@ static void atmel_console_write(struct console > *co, const char *s, u_int count) > * First, save IMR and then disable interrupts > */ > imr = UART_GET_IMR(port); > - UART_PUT_IDR(port, ATMEL_US_RXRDY | ATMEL_US_TXRDY); > + UART_PUT_IDR(port, ATMEL_US_RXRDY | atmel_port->tx_done_mask); > > /* Store PDC transmit status and disable it */ > pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN; > @@ -1355,7 +1530,7 @@ static void atmel_console_write(struct console > *co, const char *s, u_int count) > */ > do { > status = UART_GET_CSR(port); > - } while (!(status & ATMEL_US_TXRDY)); > + } while (!(status & atmel_port->tx_done_mask)); > > /* Restore PDC transmit status */ > if (pdc_tx) > @@ -1587,7 +1762,7 @@ static int __devinit atmel_serial_probe(struct > platform_device *pdev) > device_init_wakeup(&pdev->dev, 1); > platform_set_drvdata(pdev, port); > > - return 0; > + return device_create_file(&(pdev->dev), &dev_attr_rs485); > > err_add_port: > kfree(port->rx_ring.buf); > @@ -1619,6 +1794,8 @@ static int __devexit atmel_serial_remove(struct > platform_device *pdev) > > clk_put(atmel_port->clk); > > + device_remove_file(&(pdev->dev), &dev_attr_rs485); > + > return ret; > } > > -- > 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Claudio Scordino on 22 Mar 2010 07:20
Hi Ryan, first of all, thank you for your feedback. To me, all comments seem to be reasonable, except maybe the following one: >> >> +static void atmel_start_rx(struct uart_port *port); >> +static void atmel_stop_rx(struct uart_port *port); > > Can you move these functions, so that these declarations are not needed? Actually, atmel_stop_rx is already defined, and I prefer to not move it (since I change it, people may get confused by the diff...). I also think that atmel_start_rx (which is added by the patch) should be near to atmel_stop_rx... >> + UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT | >> port->read_status_mask); > > This line, and a couple of others, extend over 80 characters. Could you > please split them up. Of course. I'm going to split them up and use a backslash at the end of the original lines. I will create a new patch according to your comments, test it and submit again to the mailing list. Many thanks again, Claudio -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |