On Fri, Apr 25, 2014 at 4:56 PM, Richard Genoud
<richard.genoud@xxxxxxxxx> wrote:
> 2014-04-22 15:08 GMT+02:00 Yegor Yefremov <yegor_sub1@xxxxxxxxxxxxxxxx>:
>> 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?
> Sorry, but I don't really get what you're trying to do.
> Could you explain a little bit more ?
Never mind, I've solved this in this patch:
http://www.spinics.net/lists/arm-kernel/msg325197.html via using
gpiod_set_value() and gpiod_get_value() directly.
Yegor
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