| Message ID | 20210618145153.1906-1-LinoSanfilippo@gmx.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] serial: amba-pl011: add RS485 support | expand |
On Fri, Jun 18, 2021 at 04:51:53PM +0200, Lino Sanfilippo wrote: > Add basic support for RS485: Provide a callback to configure RS485 > settings. Handle the RS485 specific part in the functions > pl011_rs485_tx_start() and pl011_rs485_tx_stop() which extend the generic > start/stop callbacks. > Beside via IOCTL from userspace RS485 can be enabled by means of the > device tree property "rs485-enabled-at-boot-time". > > Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> > --- > This patch applies against Gregs tty-testing branch and was tested on a > Raspberry Pi CM3. > > Changes in V2: > - clamp RTS delays to 100ms as suggested by Jiri Slaby > - instead of counting bits "by hand" use the new function tty_get_frame_size() > (also suggested by Jiri) > - use the term RS485 consistently in the commit message > - remove one blank line > > > drivers/tty/serial/amba-pl011.c | 152 +++++++++++++++++++++++++++++++- > 1 file changed, 150 insertions(+), 2 deletions(-) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index e14f3378b8a0..92c6b08d56fb 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c > @@ -265,6 +265,8 @@ struct uart_amba_port { > unsigned int old_cr; /* state during shutdown */ > unsigned int fixed_baud; /* vendor-set fixed baud rate */ > char type[12]; > + bool rs485_tx_started; > + unsigned int rs485_tx_drain_interval; /* usecs */ > #ifdef CONFIG_DMA_ENGINE > /* DMA stuff */ > bool using_tx_dma; > @@ -275,6 +277,8 @@ struct uart_amba_port { > #endif > }; > > +static unsigned int pl011_tx_empty(struct uart_port *port); > + > static unsigned int pl011_reg_to_offset(const struct uart_amba_port *uap, > unsigned int reg) > { > @@ -1282,6 +1286,34 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) > #define pl011_dma_flush_buffer NULL > #endif > > +static int pl011_rs485_tx_stop(struct uart_amba_port *uap) > +{ > + struct uart_port *port = &uap->port; > + u32 cr; > + > + /* Wait until hardware tx queue is empty */ > + while (!pl011_tx_empty(port)) > + udelay(uap->rs485_tx_drain_interval); No way out if the hardware doesn't ever empty? Shouldn't you have an "upper bound" on this loop somehow? > + > + if (port->rs485.delay_rts_after_send) > + mdelay(port->rs485.delay_rts_after_send); > + > + cr = pl011_read(uap, REG_CR); > + > + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) > + cr &= ~UART011_CR_RTS; > + else > + cr |= UART011_CR_RTS; Blank line here please. > + /* Disable the transmitter and reenable the transceiver */ > + cr &= ~UART011_CR_TXE; > + cr |= UART011_CR_RXE; > + pl011_write(cr, uap, REG_CR); > + > + uap->rs485_tx_started = false; > + > + return 0; Why does this function return a value if it can not fail and you do not check the return value of it? > +} > + > static void pl011_stop_tx(struct uart_port *port) > { > struct uart_amba_port *uap = > @@ -1290,6 +1322,9 @@ static void pl011_stop_tx(struct uart_port *port) > uap->im &= ~UART011_TXIM; > pl011_write(uap->im, uap, REG_IMSC); > pl011_dma_tx_stop(uap); > + > + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) > + pl011_rs485_tx_stop(uap); So, no check :( > } > > static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq); > @@ -1380,6 +1415,31 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, > return true; > } > > +static void pl011_rs485_tx_start(struct uart_amba_port *uap) > +{ > + struct uart_port *port = &uap->port; > + u32 cr; > + > + /* Enable transmitter */ > + cr = pl011_read(uap, REG_CR); > + cr |= UART011_CR_TXE; Blank line please. > + /* Disable receiver if half-duplex */ > + if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) > + cr &= ~UART011_CR_RXE; > + > + if (port->rs485.flags & SER_RS485_RTS_ON_SEND) > + cr &= ~UART011_CR_RTS; > + else > + cr |= UART011_CR_RTS; > + > + pl011_write(cr, uap, REG_CR); > + > + if (port->rs485.delay_rts_before_send) > + mdelay(port->rs485.delay_rts_before_send); > + > + uap->rs485_tx_started = true; > +} > + > /* Returns true if tx interrupts have to be (kept) enabled */ > static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) > { > @@ -1397,6 +1457,10 @@ static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) > return false; > } > > + if ((uap->port.rs485.flags & SER_RS485_ENABLED) && > + !uap->rs485_tx_started) > + pl011_rs485_tx_start(uap); > + > /* If we are using DMA mode, try to send some characters. */ > if (pl011_dma_tx_irq(uap)) > return true; > @@ -1542,6 +1606,9 @@ static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) > container_of(port, struct uart_amba_port, port); > unsigned int cr; > > + if (port->rs485.flags & SER_RS485_ENABLED) > + mctrl &= ~TIOCM_RTS; > + > cr = pl011_read(uap, REG_CR); > > #define TIOCMBIT(tiocmbit, uartbit) \ > @@ -1763,7 +1830,17 @@ static int pl011_startup(struct uart_port *port) > > /* restore RTS and DTR */ > cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR); > - cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE; > + cr |= UART01x_CR_UARTEN | UART011_CR_RXE; > + > + if (port->rs485.flags & SER_RS485_ENABLED) { > + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) > + cr &= ~UART011_CR_RTS; > + else > + cr |= UART011_CR_RTS; > + } else { > + cr |= UART011_CR_TXE; > + } > + > pl011_write(cr, uap, REG_CR); > > spin_unlock_irq(&uap->port.lock); > @@ -1864,6 +1941,9 @@ static void pl011_shutdown(struct uart_port *port) > > pl011_dma_shutdown(uap); > > + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) > + pl011_rs485_tx_stop(uap); > + > free_irq(uap->port.irq, uap); > > pl011_disable_uart(uap); > @@ -1941,6 +2021,7 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, > unsigned int lcr_h, old_cr; > unsigned long flags; > unsigned int baud, quot, clkdiv; > + unsigned int bits; > > if (uap->vendor->oversampling) > clkdiv = 8; > @@ -1991,18 +2072,29 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, > if (uap->fifosize > 1) > lcr_h |= UART01x_LCRH_FEN; > > + bits = tty_get_frame_size(termios->c_cflag); > + > spin_lock_irqsave(&port->lock, flags); > > /* > * Update the per-port timeout. > */ > uart_update_timeout(port, termios->c_cflag, baud); Blank line > + /* > + * Calculate the approximated time it takes to transmit one character > + * with the given baud rate. We use this as the poll interval when we > + * wait for the tx queue to empty. > + */ > + uap->rs485_tx_drain_interval = (bits * 1000 * 1000) / baud; > > pl011_setup_status_masks(port, termios); > > if (UART_ENABLE_MS(port, termios->c_cflag)) > pl011_enable_ms(port); > > + if (port->rs485.flags & SER_RS485_ENABLED) > + termios->c_cflag &= ~CRTSCTS; > + > /* first, disable everything */ > old_cr = pl011_read(uap, REG_CR); > pl011_write(0, uap, REG_CR); > @@ -2124,6 +2216,40 @@ static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser) > return ret; > } > > +static int pl011_rs485_config(struct uart_port *port, > + struct serial_rs485 *rs485) > +{ > + struct uart_amba_port *uap = > + container_of(port, struct uart_amba_port, port); > + > + /* pick sane settings if the user hasn't */ > + if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) == Why the !! in an if statement? > + !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { Same here, why? > + rs485->flags |= SER_RS485_RTS_ON_SEND; > + rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; > + } > + /* clamp the delays to [0, 100ms] */ > + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); > + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); > + memset(rs485->padding, 0, sizeof(rs485->padding)); > + > + if (port->rs485.flags & SER_RS485_ENABLED) > + pl011_rs485_tx_stop(uap); > + > + /* Set new configuration */ > + port->rs485 = *rs485; Blank line please. > + /* Make sure auto RTS is disabled */ > + if (port->rs485.flags & SER_RS485_ENABLED) { > + u32 cr = pl011_read(uap, REG_CR); > + > + cr &= ~UART011_CR_RTSEN; > + pl011_write(cr, uap, REG_CR); > + port->status &= ~UPSTAT_AUTORTS; > + } > + > + return 0; > +} > + thanks, greg k-h
Hi, On 24.06.21 at 14:55, Greg KH wrote: >> >> +static int pl011_rs485_tx_stop(struct uart_amba_port *uap) >> +{ >> + struct uart_port *port = &uap->port; >> + u32 cr; >> + >> + /* Wait until hardware tx queue is empty */ >> + while (!pl011_tx_empty(port)) >> + udelay(uap->rs485_tx_drain_interval); > > No way out if the hardware doesn't ever empty? Shouldn't you have an > "upper bound" on this loop somehow? Yes, indeed. I will fix this. > >> + >> + if (port->rs485.delay_rts_after_send) >> + mdelay(port->rs485.delay_rts_after_send); >> + >> + cr = pl011_read(uap, REG_CR); >> + >> + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) >> + cr &= ~UART011_CR_RTS; >> + else >> + cr |= UART011_CR_RTS; > > Blank line here please. Ok. > >> + /* Disable the transmitter and reenable the transceiver */ >> + cr &= ~UART011_CR_TXE; >> + cr |= UART011_CR_RXE; >> + pl011_write(cr, uap, REG_CR); >> + >> + uap->rs485_tx_started = false; >> + >> + return 0; > > Why does this function return a value if it can not fail and you do not > check the return value of it? >> +} >> + >> static void pl011_stop_tx(struct uart_port *port) >> { >> struct uart_amba_port *uap = >> @@ -1290,6 +1322,9 @@ static void pl011_stop_tx(struct uart_port *port) >> uap->im &= ~UART011_TXIM; >> pl011_write(uap->im, uap, REG_IMSC); >> pl011_dma_tx_stop(uap); >> + >> + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) >> + pl011_rs485_tx_stop(uap); > > So, no check :( > Ah, right. The return value is a leftover from an earlier version of the function. I will correct this in the next patch version. > >> } >> >> static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq); >> @@ -1380,6 +1415,31 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, >> return true; >> } >> >> +static void pl011_rs485_tx_start(struct uart_amba_port *uap) >> +{ >> + struct uart_port *port = &uap->port; >> + u32 cr; >> + >> + /* Enable transmitter */ >> + cr = pl011_read(uap, REG_CR); >> + cr |= UART011_CR_TXE; > > Blank line please. > Ok. >> + >> spin_lock_irqsave(&port->lock, flags); >> >> /* >> * Update the per-port timeout. >> */ >> uart_update_timeout(port, termios->c_cflag, baud); > > Blank line > Ok. >> >> +static int pl011_rs485_config(struct uart_port *port, >> + struct serial_rs485 *rs485) >> +{ >> + struct uart_amba_port *uap = >> + container_of(port, struct uart_amba_port, port); >> + >> + /* pick sane settings if the user hasn't */ >> + if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) == > > Why the !! in an if statement? > >> + !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { > > Same here, why? > This was copied from serial8250_em485_config(). But I think we can simply use if (rs485->flags & SER_RS485_RTS_AFTER_SEND) rs485->flags &= ~SER_RS485_RTS_ON_SEND; else rs485->flags |= SER_RS485_RTS_ON_SEND; instead. I will adjust the code accordingly. >> + >> + if (port->rs485.flags & SER_RS485_ENABLED) >> + pl011_rs485_tx_stop(uap); >> + >> + /* Set new configuration */ >> + port->rs485 = *rs485; > > Blank line please. > Ok. > > thanks, > > greg k-h > Thank you for the review! Regards, Lino
On 25. 06. 21, 2:15, Lino Sanfilippo wrote: >>> +static int pl011_rs485_config(struct uart_port *port, >>> + struct serial_rs485 *rs485) >>> +{ >>> + struct uart_amba_port *uap = >>> + container_of(port, struct uart_amba_port, port); >>> + >>> + /* pick sane settings if the user hasn't */ >>> + if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) == >> >> Why the !! in an if statement? >> >>> + !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { >> >> Same here, why? >> > > This was copied from serial8250_em485_config(). But I think we can simply use > > if (rs485->flags & SER_RS485_RTS_AFTER_SEND) > rs485->flags &= ~SER_RS485_RTS_ON_SEND; > else > rs485->flags |= SER_RS485_RTS_ON_SEND; > > instead. I will adjust the code accordingly. This is different. You want to set ON_SEND when none is set. And unset AFTER_SEND when both are set. In your code, when both are set, you leave AFTER_SEND. regards, -- js suse labs
Hi, > On 25. 06. 21, 2:15, Lino Sanfilippo wrote: > >>> +static int pl011_rs485_config(struct uart_port *port, > >>> + struct serial_rs485 *rs485) > >>> +{ > >>> + struct uart_amba_port *uap = > >>> + container_of(port, struct uart_amba_port, port); > >>> + > >>> + /* pick sane settings if the user hasn't */ > >>> + if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) == > >> > >> Why the !! in an if statement? > >> > >>> + !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { > >> > >> Same here, why? > >> > > > > This was copied from serial8250_em485_config(). But I think we can simply use > > > > if (rs485->flags & SER_RS485_RTS_AFTER_SEND) > > rs485->flags &= ~SER_RS485_RTS_ON_SEND; > > else > > rs485->flags |= SER_RS485_RTS_ON_SEND; > > > > instead. I will adjust the code accordingly. > > This is different. You want to set ON_SEND when none is set. And unset > AFTER_SEND when both are set. In your code, when both are set, you leave > AFTER_SEND. > > regards, > -- > js > suse labs > Thats right, the logic has slightly changed. I thought this does not matter as long as we make sure that exactly one of both ON_SEND or AFTER_SEND is set. We can stick with the logic in serial8250_em485_config() (i.e. always set ON_SEND and delete AFTER_SEND in case of an invalid setting), but I think this will require more than the four lines that we have now (especially if we want to avoid the !!). Thanks, Lino
Hi, On 25. 06. 21, 13:21, Lino Sanfilippo wrote: > Thats right, the logic has slightly changed. I thought this does not matter as long as > we make sure that exactly one of both ON_SEND or AFTER_SEND is set. I actually don't know. But I would remain consistent with other drivers. > We can stick with the logic > in serial8250_em485_config() (i.e. always set ON_SEND and delete AFTER_SEND in case > of an invalid setting), but I think this will require more than the four lines that we > have now (especially if we want to avoid the !!). What if you used only a single !? thanks, -- js suse labs
Hi, On 26.06.21 at 05:41, Jiri Slaby wrote: > On 25. 06. 21, 13:21, Lino Sanfilippo wrote: >> Thats right, the logic has slightly changed. I thought this does not matter as long as >> we make sure that exactly one of both ON_SEND or AFTER_SEND is set. > > I actually don't know. But I would remain consistent with other drivers. > >> We can stick with the logic >> in serial8250_em485_config() (i.e. always set ON_SEND and delete AFTER_SEND in case >> of an invalid setting), but I think this will require more than the four lines that we >> have now (especially if we want to avoid the !!). > > What if you used only a single !? > You are right, this is the easiest way to keep the current logic. I will do that. Thanks, Lino
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index e14f3378b8a0..92c6b08d56fb 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -265,6 +265,8 @@ struct uart_amba_port { unsigned int old_cr; /* state during shutdown */ unsigned int fixed_baud; /* vendor-set fixed baud rate */ char type[12]; + bool rs485_tx_started; + unsigned int rs485_tx_drain_interval; /* usecs */ #ifdef CONFIG_DMA_ENGINE /* DMA stuff */ bool using_tx_dma; @@ -275,6 +277,8 @@ struct uart_amba_port { #endif }; +static unsigned int pl011_tx_empty(struct uart_port *port); + static unsigned int pl011_reg_to_offset(const struct uart_amba_port *uap, unsigned int reg) { @@ -1282,6 +1286,34 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) #define pl011_dma_flush_buffer NULL #endif +static int pl011_rs485_tx_stop(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + u32 cr; + + /* Wait until hardware tx queue is empty */ + while (!pl011_tx_empty(port)) + udelay(uap->rs485_tx_drain_interval); + + if (port->rs485.delay_rts_after_send) + mdelay(port->rs485.delay_rts_after_send); + + cr = pl011_read(uap, REG_CR); + + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + cr &= ~UART011_CR_RTS; + else + cr |= UART011_CR_RTS; + /* Disable the transmitter and reenable the transceiver */ + cr &= ~UART011_CR_TXE; + cr |= UART011_CR_RXE; + pl011_write(cr, uap, REG_CR); + + uap->rs485_tx_started = false; + + return 0; +} + static void pl011_stop_tx(struct uart_port *port) { struct uart_amba_port *uap = @@ -1290,6 +1322,9 @@ static void pl011_stop_tx(struct uart_port *port) uap->im &= ~UART011_TXIM; pl011_write(uap->im, uap, REG_IMSC); pl011_dma_tx_stop(uap); + + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) + pl011_rs485_tx_stop(uap); } static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq); @@ -1380,6 +1415,31 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, return true; } +static void pl011_rs485_tx_start(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + u32 cr; + + /* Enable transmitter */ + cr = pl011_read(uap, REG_CR); + cr |= UART011_CR_TXE; + /* Disable receiver if half-duplex */ + if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) + cr &= ~UART011_CR_RXE; + + if (port->rs485.flags & SER_RS485_RTS_ON_SEND) + cr &= ~UART011_CR_RTS; + else + cr |= UART011_CR_RTS; + + pl011_write(cr, uap, REG_CR); + + if (port->rs485.delay_rts_before_send) + mdelay(port->rs485.delay_rts_before_send); + + uap->rs485_tx_started = true; +} + /* Returns true if tx interrupts have to be (kept) enabled */ static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) { @@ -1397,6 +1457,10 @@ static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) return false; } + if ((uap->port.rs485.flags & SER_RS485_ENABLED) && + !uap->rs485_tx_started) + pl011_rs485_tx_start(uap); + /* If we are using DMA mode, try to send some characters. */ if (pl011_dma_tx_irq(uap)) return true; @@ -1542,6 +1606,9 @@ static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) container_of(port, struct uart_amba_port, port); unsigned int cr; + if (port->rs485.flags & SER_RS485_ENABLED) + mctrl &= ~TIOCM_RTS; + cr = pl011_read(uap, REG_CR); #define TIOCMBIT(tiocmbit, uartbit) \ @@ -1763,7 +1830,17 @@ static int pl011_startup(struct uart_port *port) /* restore RTS and DTR */ cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR); - cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE; + cr |= UART01x_CR_UARTEN | UART011_CR_RXE; + + if (port->rs485.flags & SER_RS485_ENABLED) { + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + cr &= ~UART011_CR_RTS; + else + cr |= UART011_CR_RTS; + } else { + cr |= UART011_CR_TXE; + } + pl011_write(cr, uap, REG_CR); spin_unlock_irq(&uap->port.lock); @@ -1864,6 +1941,9 @@ static void pl011_shutdown(struct uart_port *port) pl011_dma_shutdown(uap); + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) + pl011_rs485_tx_stop(uap); + free_irq(uap->port.irq, uap); pl011_disable_uart(uap); @@ -1941,6 +2021,7 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, unsigned int lcr_h, old_cr; unsigned long flags; unsigned int baud, quot, clkdiv; + unsigned int bits; if (uap->vendor->oversampling) clkdiv = 8; @@ -1991,18 +2072,29 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, if (uap->fifosize > 1) lcr_h |= UART01x_LCRH_FEN; + bits = tty_get_frame_size(termios->c_cflag); + spin_lock_irqsave(&port->lock, flags); /* * Update the per-port timeout. */ uart_update_timeout(port, termios->c_cflag, baud); + /* + * Calculate the approximated time it takes to transmit one character + * with the given baud rate. We use this as the poll interval when we + * wait for the tx queue to empty. + */ + uap->rs485_tx_drain_interval = (bits * 1000 * 1000) / baud; pl011_setup_status_masks(port, termios); if (UART_ENABLE_MS(port, termios->c_cflag)) pl011_enable_ms(port); + if (port->rs485.flags & SER_RS485_ENABLED) + termios->c_cflag &= ~CRTSCTS; + /* first, disable everything */ old_cr = pl011_read(uap, REG_CR); pl011_write(0, uap, REG_CR); @@ -2124,6 +2216,40 @@ static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser) return ret; } +static int pl011_rs485_config(struct uart_port *port, + struct serial_rs485 *rs485) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + /* pick sane settings if the user hasn't */ + if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) == + !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { + rs485->flags |= SER_RS485_RTS_ON_SEND; + rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; + } + /* clamp the delays to [0, 100ms] */ + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); + memset(rs485->padding, 0, sizeof(rs485->padding)); + + if (port->rs485.flags & SER_RS485_ENABLED) + pl011_rs485_tx_stop(uap); + + /* Set new configuration */ + port->rs485 = *rs485; + /* Make sure auto RTS is disabled */ + if (port->rs485.flags & SER_RS485_ENABLED) { + u32 cr = pl011_read(uap, REG_CR); + + cr &= ~UART011_CR_RTSEN; + pl011_write(cr, uap, REG_CR); + port->status &= ~UPSTAT_AUTORTS; + } + + return 0; +} + static const struct uart_ops amba_pl011_pops = { .tx_empty = pl011_tx_empty, .set_mctrl = pl011_set_mctrl, @@ -2588,10 +2714,28 @@ static int pl011_find_free_port(void) return -EBUSY; } +static int pl011_get_rs485_mode(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + struct serial_rs485 *rs485 = &port->rs485; + int ret; + + ret = uart_get_rs485_mode(port); + if (ret) + return ret; + + /* clamp the delays to [0, 100ms] */ + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); + + return 0; +} + static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap, struct resource *mmiobase, int index) { void __iomem *base; + int ret; base = devm_ioremap_resource(dev, mmiobase); if (IS_ERR(base)) @@ -2608,6 +2752,10 @@ static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap, uap->port.flags = UPF_BOOT_AUTOCONF; uap->port.line = index; + ret = pl011_get_rs485_mode(uap); + if (ret) + return ret; + amba_ports[index] = uap; return 0; @@ -2665,7 +2813,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id) uap->port.iotype = vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; uap->port.irq = dev->irq[0]; uap->port.ops = &amba_pl011_pops; - + uap->port.rs485_config = pl011_rs485_config; snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev)); ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr);
Add basic support for RS485: Provide a callback to configure RS485 settings. Handle the RS485 specific part in the functions pl011_rs485_tx_start() and pl011_rs485_tx_stop() which extend the generic start/stop callbacks. Beside via IOCTL from userspace RS485 can be enabled by means of the device tree property "rs485-enabled-at-boot-time". Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> --- This patch applies against Gregs tty-testing branch and was tested on a Raspberry Pi CM3. Changes in V2: - clamp RTS delays to 100ms as suggested by Jiri Slaby - instead of counting bits "by hand" use the new function tty_get_frame_size() (also suggested by Jiri) - use the term RS485 consistently in the commit message - remove one blank line drivers/tty/serial/amba-pl011.c | 152 +++++++++++++++++++++++++++++++- 1 file changed, 150 insertions(+), 2 deletions(-) base-commit: b61c8bf4694b5115766849378dcb8787ff54e65e