Messages in this thread | | | Subject | Re: [PATCH 2/2 v4] tty/serial/8250: use mctrl_gpio helpers | From | Stefan Roese <> | Date | Wed, 5 Jun 2019 11:35:01 +0200 |
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On 04.06.19 18:52, Andy Shevchenko wrote: > On Mon, Jun 03, 2019 at 10:33:32AM +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. > >> + if (up->gpios) { > >> + mctrl_gpio_set(up->gpios, mctrl_gpio); >> + } > > ... > >> + if (up->gpios) { > >> + mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); > >> + } > > ... > >> + gpios = mctrl_gpio_init(&uart->port, 0); >> + if (IS_ERR(gpios)) { >> + if (PTR_ERR(gpios) != -ENOSYS) >> + return PTR_ERR(gpios); >> + } > > ... > >> + if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, >> + UART_GPIO_RTS))) { > >> + } > > ... > >> - if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) { >> + if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW >> + && IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(up->gpios, >> + UART_GPIO_RTS))) { > >> } > > ... > >> + if (up->gpios) >> + mctrl_gpio_disable_ms(up->gpios); > > ... > >> + if (up->gpios) >> + mctrl_gpio_enable_ms(up->gpios); > > ... > >> + if (up->gpios) >> + return mctrl_gpio_get(up->gpios, &ret); > > > Can we rather make this mimic the gpiod_get_optional() API? > > So, if we get an error, it's an error, otherwise with NULL pointer the > operations goes to be no-op. > > [IS_ERR_OR_NULL() -> IS_ERR(), if (up->gpios) -> /dev/null, etc]
So you want me to drop all "if (up->gpios)" checks? I can do this in some cases (e.g. serial8250_disable_ms()). But I would like to keep it in other cases, like serial8250_out_MCR(), where this check prevents some unnecessary code execution in the "non-gpios mode" (and vice-versa).
Would this be acceptable?
BTW: Regarding the OMAP specific code: I'm not the author of this code and I don't have access to such hardware to do some tests here. But changing IS_ERR_OR_NULL() -> IS_ERR() in this OMAP code does not seem correct. IIUTC, these "if" clauses are extended here by IS_ERR_OR_NULL(mctrl_gpio_to_gpiod()) to check if the GPIO's are not enabled / used. Currently this will probably break, since when called with "gpios == NULL", mctrl_gpio_to_gpiod() will crash [1].
If you don't object (or have other suggestions), I'll change this to use "up->gpios == 0" instead. This seems to be what the original author wanted to achieve.
Okay?
Thanks, Stefan
[1]
struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, enum mctrl_gpio_idx gidx) { return gpios->gpio[gidx]; }
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