Messages in this thread | | | Subject | Re: [PATCH 2/2 v5] tty/serial/8250: use mctrl_gpio helpers | From | Stefan Roese <> | Date | Tue, 11 Jun 2019 16:02:54 +0200 |
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On 11.06.19 14:44, Andy Shevchenko wrote: > On Tue, Jun 11, 2019 at 12:56:03PM +0200, Stefan Roese wrote: >> From: Yegor Yefremov <yegorslists@googlemail.com> >> >> This patch permits the usage for GPIOs to control >> the CTS/RTS/DTR/DSR/DCD/RI signals. > >> static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) >> { >> serial_out(up, UART_MCR, value); >> + >> + if (up->gpios) { >> + int mctrl_gpio = 0; >> + >> + if (value & UART_MCR_RTS) >> + mctrl_gpio |= TIOCM_RTS; >> + if (value & UART_MCR_DTR) >> + mctrl_gpio |= TIOCM_DTR; >> + >> + mctrl_gpio_set(up->gpios, mctrl_gpio); >> + } >> } >> >> static inline int serial8250_in_MCR(struct uart_8250_port *up) >> { >> - return serial_in(up, UART_MCR); >> + int mctrl; >> + >> + mctrl = serial_in(up, UART_MCR); >> + >> + if (up->gpios) { >> + int mctrl_gpio = 0; >> + >> + /* save current MCR values */ >> + if (mctrl & UART_MCR_RTS) >> + mctrl_gpio |= TIOCM_RTS; >> + if (mctrl & UART_MCR_DTR) >> + mctrl_gpio |= TIOCM_DTR; >> + >> + mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); >> + if (mctrl_gpio & TIOCM_RTS) >> + mctrl |= UART_MCR_RTS; >> + else >> + mctrl &= ~UART_MCR_RTS; >> + >> + if (mctrl_gpio & TIOCM_DTR) >> + mctrl |= UART_MCR_DTR; >> + else >> + mctrl &= ~UART_MCR_DTR; >> + } >> + >> + return mctrl; >> } > > These are using OR logic with potentially volatile data. Shouldn't we mask > unused bits in UART_MCR in case of up->gpios != NULL?
Sorry, I don't see, which bits you are referring to? Could you please be a bit more specific with the variable / macro meant (example)?
>> + if (up->gpios == 0) > > This is type inconsistency with this check as far as I understand. > I guess you have to do either (up->gpios == NULL), or (!up->gpios).
Ah, right. Thanks for spotting.
Thanks, Stefan
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