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@xxxxxxxxxxxxxx>
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
