Other NXP ProductsのトピックPCA9533 linux driver

PCA9533 linux driver

lidiah — Wed, 01 Sep 2021 08:56:03 GMT

Hi.

i'm working with pca9533 i2c led dimmer. Looking at the linux driver drivers/leds/leds-pca9532.c, i have some doubts about the define of the control register:

/* m = num_leds*/ #define PCA9532_REG_INPUT(i) ((i) >> 3) #define PCA9532_REG_OFFSET(m) ((m) >> 4) #define PCA9532_REG_PSC(m, i) (PCA9532_REG_OFFSET(m) + 0x1 + (i) * 2) #define PCA9532_REG_PWM(m, i) (PCA9532_REG_OFFSET(m) + 0x2 + (i) * 2) #define LED_REG(m, led) (PCA9532_REG_OFFSET(m) + 0x5 + (led >> 2)) #define LED_NUM(led) (led & 0x3) #define LED_SHIFT(led) (LED_NUM(led) * 2) #define LED_MASK(led) (0x3 << LED_SHIFT(led))

In particular, why is LED_REG defined with the shifts? Shouldn't it be just 0x5 as the datasheet says?

Thank you

Re: PCA9533 linux driver

TomasVaverka — Wed, 01 Sep 2021 11:39:08 GMT

Hi Lidia,

I am not familiar with this driver, but for the PCA9533 (4-bit I2C-bus LED dimmer), the address of the LS0 - LED selector register is indeed 0x05, so the second byte when writing to or reading from this register has to be 0x05.

Best regards,

Tomas

Re: PCA9533 linux driver

lidiah — Wed, 01 Sep 2021 11:57:42 GMT

Thank you,

that's why i was asking about the shifts #define LED_REG(m, led) (PCA9532_REG_OFFSET(m) + 0x5 + (led >> 2)).

maybe they have no effects on the writing/reading.

Lidia