On 10.03.2014 17:45, Richard Genoud wrote:
> This patch add some helpers to control modem lines (CTS/RTS/DSR...) via
> GPIO.
> This will be useful for many boards which have a serial controller that
> only handle CTS/RTS pins (or even just RX/TX).
>
> Signed-off-by: Richard Genoud <richard.genoud@xxxxxxxxx>
....
> +
> +struct mctrl_gpios {
> + struct gpio_desc *gpio[UART_GPIO_MAX];
> +};
> +
> +static const struct {
> + const char *name;
> + unsigned int mctrl;
> + bool dir_out;
> +} mctrl_gpios_desc[UART_GPIO_MAX] = {
> + { "cts", TIOCM_CTS, false, },
> + { "dsr", TIOCM_DSR, false, },
> + { "dcd", TIOCM_CD, false, },
> + { "rng", TIOCM_RNG, false, },
> + { "rts", TIOCM_RTS, true, },
> + { "dtr", TIOCM_DTR, true, },
> + { "out1", TIOCM_OUT1, true, },
> + { "out2", TIOCM_OUT2, true, },
> +};
> +
> +void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
> +{
> + enum mctrl_gpio_idx i;
> +
> + if (IS_ERR_OR_NULL(gpios))
> + return;
> +
> + for (i = 0; i < UART_GPIO_MAX; i++)
> + if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
> + mctrl_gpios_desc[i].dir_out)
> + gpiod_set_value(gpios->gpio[i],
> + !!(mctrl & mctrl_gpios_desc[i].mctrl));
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_set);
> +
> +struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> + enum mctrl_gpio_idx gidx)
> +{
> + if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx]))
> + return gpios->gpio[gidx];
> + else
> + return NULL;
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
> +
> +unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
> +{
> + enum mctrl_gpio_idx i;
> +
> + /*
> + * return it unchanged if the structure is not allocated
> + */
> + if (IS_ERR_OR_NULL(gpios))
> + return *mctrl;
> +
> + for (i = 0; i < UART_GPIO_MAX; i++) {
> + if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
> + !mctrl_gpios_desc[i].dir_out) {
> + if (gpiod_get_value(gpios->gpio[i]))
> + *mctrl |= mctrl_gpios_desc[i].mctrl;
> + else
> + *mctrl &= ~mctrl_gpios_desc[i].mctrl;
> + }
> + }
> +
> + return *mctrl;
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_get);
Should this routine be renamed to msr_gpio_get() or perhaps better to give all values (inputs and outputs)?
I'm trying to port this approach to omap-serial to implement RS485 switching. I need to know if RTS is already on or not and set it accordingly.
What would be the best solution for this task using this new API?
Yegor
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