On Thu, Jun 25, 2026 at 09:26:47PM +0800, Sunyun Yang wrote: > Krzysztof Kozlowski <[email protected]> 于2026年6月25日周四 21:17写道： > > > > On 25/06/2026 15:14, Sunyun Yang wrote: > > > Krzysztof Kozlowski <[email protected]> 于2026年6月25日周四 20:54写道： > > >> > > >> On 08/05/2026 15:40, [email protected] wrote: > > >>> + > > >>> +static void lt9611c_reset(struct lt9611c *lt9611c) > > >>> +{ > > >>> + gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); > > >>> + msleep(20); > > >>> + > > >>> + gpiod_set_value_cansleep(lt9611c->reset_gpio, 0); > > >>> + msleep(20); > > >>> + > > >>> + gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); > > >> > > >> This is just plain wrong. Why do you assert, then de-assert and then > > >> finally assert AGAIN the reset leaving the device in powerdown stage? > > >> > > > I am using software to emulate the hardware RESET button on our EVB. > > > When the hardware RESET button is pressed while our chip is running, > > > the signal level changes from HIGH to LOW and then back to HIGH. > > > > > > Of course, we can also use the following: > > > static void lt9611c_reset(struct lt9611c *lt9611c) > > > { > > > gpiod_set_value_cansleep(lt9611c->reset_gpio, 0); > > > msleep(50); > > > gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); > > > msleep(20); > > > } > > > > Makes no sense either and you just did not get the point and did not > > answer my question. I asked WHY you leave asserted. Answer "we emulate" > > is just plain wrong. > > > > So again please answer: > > > > Why do you leave device with reset asserted? > > > > devicetree: reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;
It should be GPIO_ACTIVE_LOW, if the pin as active-low. > > GPIO_ACTIVE_HIGH: > > gpiod_set_value_cansleep(lt9611c->reset_gpio, 0); ------ reset pin > is Low level : Clear the register configuration in the chip to stop > the chip from working. > > gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); ------ reset pin > is high level: The chip resumes operation. > > > > > Best regards, > > Krzysztof -- With best wishes Dmitry
