On 26/06/2026 04:15, Sunyun Yang wrote: > Krzysztof Kozlowski <[email protected]> 于2026年6月25日周四 21:51写道： >> >> On 25/06/2026 15:40, Sunyun Yang wrote: >>> Sunyun Yang <[email protected]> 于2026年6月25日周四 21:26写道： >>>> >>>> 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>; >>>> >>>> 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. >>>> >>>> >>> >>> Our purpose is: pull the level low to clear the register configuration >>> in the chip, and then pull it high to allow the MCU inside the chip to >>> re‑initialize the registers. >> >> >> And you do completely opposite... so that confirms your code is just wrong. >> > > The lontium-lt9611.yaml uses GPIO_ACTIVE_HIGH. I am just following the > rule of this device tree. If I modify the device tree to use > GPIO_ACTIVE_LOW, > and use the following code in my driver, then my driver would be correct. > However, would the existing kernel drivers lontium-lt9611uxc.c and > lontium-lt9611.c be affected?
DT has nothing to do here. 1 is assert, 0 is de-assert. Your code does things opposite to any logic, because you finish function with reset asserted. Best regards, Krzysztof
