Re: [PATCH] misc/pca9552: Fix inverted input status

[Cédric Le Goater]

On 9/27/23 22:32, Glenn Miles wrote:
> The pca9552 INPUT0 and INPUT1 registers are supposed to
> hold the logical values of the LED pins.  A logical 0
> should be seen in the INPUT0/1 registers for a pin when
> its corresponding LSn bits are set to 0, which is also
> the state needed for turning on an LED in a typical
> usage scenario.  Existing code was doing the opposite
> and setting INPUT0/1 bit to a 1 when the LSn bit was
> set to 0, so this commit fixes that.
>
> Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>

Looks OK to me.

May be you could mention that the ON/OFF values are reversed on
the pca953x family. This is good to know if one wants to model
these devices one day.

Reviewed-by: Cédric Le Goater <clg@kaod.org>

Thanks,

C.


> ---
>   hw/misc/pca9552.c          | 13 +++++++++----
>   tests/qtest/pca9552-test.c |  6 +++---
>   2 files changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/hw/misc/pca9552.c b/hw/misc/pca9552.c
> index fff19e369a..ad811fb249 100644
> --- a/hw/misc/pca9552.c
> +++ b/hw/misc/pca9552.c
> @@ -112,13 +112,18 @@ static void pca955x_update_pin_input(PCA955xState *s)
>   
>           switch (config) {
>           case PCA9552_LED_ON:
> -            qemu_set_irq(s->gpio[i], 1);
> -            s->regs[input_reg] |= 1 << input_shift;
> -            break;
> -        case PCA9552_LED_OFF:
> +            /* Pin is set to 0V to turn on LED */
>               qemu_set_irq(s->gpio[i], 0);
>               s->regs[input_reg] &= ~(1 << input_shift);
>               break;
> +        case PCA9552_LED_OFF:
> +            /*
> +             * Pin is set to Hi-Z to turn off LED and
> +             * pullup sets it to a logical 1.
> +             */
> +            qemu_set_irq(s->gpio[i], 1);
> +            s->regs[input_reg] |= 1 << input_shift;
> +            break;
>           case PCA9552_LED_PWM0:
>           case PCA9552_LED_PWM1:
>               /* TODO */
> diff --git a/tests/qtest/pca9552-test.c b/tests/qtest/pca9552-test.c
> index d80ed93cd3..ccca2b3d91 100644
> --- a/tests/qtest/pca9552-test.c
> +++ b/tests/qtest/pca9552-test.c
> @@ -60,7 +60,7 @@ static void send_and_receive(void *obj, void *data, 
> QGuestAllocator *alloc)
>       g_assert_cmphex(value, ==, 0x55);
>   
>       value = i2c_get8(i2cdev, PCA9552_INPUT0);
> -    g_assert_cmphex(value, ==, 0x0);
> +    g_assert_cmphex(value, ==, 0xFF);
>   
>       pca9552_init(i2cdev);
>   
> @@ -68,13 +68,13 @@ static void send_and_receive(void *obj, void *data, QGuestAllocator *alloc)
>       g_assert_cmphex(value, ==, 0x54);
>   
>       value = i2c_get8(i2cdev, PCA9552_INPUT0);
> -    g_assert_cmphex(value, ==, 0x01);
> +    g_assert_cmphex(value, ==, 0xFE);
>   
>       value = i2c_get8(i2cdev, PCA9552_LS3);
>       g_assert_cmphex(value, ==, 0x54);
>   
>       value = i2c_get8(i2cdev, PCA9552_INPUT1);
> -    g_assert_cmphex(value, ==, 0x10);
> +    g_assert_cmphex(value, ==, 0xEF);
>   }
>   
>   static void pca9552_register_nodes(void)