From bce54366946a7a190a1df74f6f605412f731709c Mon Sep 17 00:00:00 2001 From: David Jander Date: Fri, 28 Aug 2020 14:14:15 +0200 Subject: pwm: pca9685: Disable unused alternative addresses The PCA9685 supports listening to 1 or more alternative I2C chip addresses for some special features that this driver does not support. By default the LED ALLCALL address is active (default 0x70), which causes this chip to respond to address 0x70 in addition to its main address (0x41). This is not desireable if there is another device on the same bus that uses this address (like a TMP103 for example). Since this feature is not supported by this driver, it is best to disable these addresses in the chip to avoid unsuspected bus collisions. Signed-off-by: David Jander Signed-off-by: Thierry Reding --- drivers/pwm/pwm-pca9685.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) (limited to 'drivers/pwm/pwm-pca9685.c') diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c index 9d1d9dece0c0..4a55dc18656c 100644 --- a/drivers/pwm/pwm-pca9685.c +++ b/drivers/pwm/pwm-pca9685.c @@ -58,6 +58,10 @@ #define PCA9685_MAXCHAN 0x10 #define LED_FULL BIT(4) +#define MODE1_ALLCALL BIT(0) +#define MODE1_SUB3 BIT(1) +#define MODE1_SUB2 BIT(2) +#define MODE1_SUB1 BIT(3) #define MODE1_SLEEP BIT(4) #define MODE2_INVRT BIT(4) #define MODE2_OUTDRV BIT(2) @@ -443,8 +447,8 @@ static int pca9685_pwm_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct pca9685 *pca; + unsigned int reg; int ret; - int mode2; pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL); if (!pca) @@ -461,19 +465,24 @@ static int pca9685_pwm_probe(struct i2c_client *client, i2c_set_clientdata(client, pca); - regmap_read(pca->regmap, PCA9685_MODE2, &mode2); + regmap_read(pca->regmap, PCA9685_MODE2, ®); if (device_property_read_bool(&client->dev, "invert")) - mode2 |= MODE2_INVRT; + reg |= MODE2_INVRT; else - mode2 &= ~MODE2_INVRT; + reg &= ~MODE2_INVRT; if (device_property_read_bool(&client->dev, "open-drain")) - mode2 &= ~MODE2_OUTDRV; + reg &= ~MODE2_OUTDRV; else - mode2 |= MODE2_OUTDRV; + reg |= MODE2_OUTDRV; + + regmap_write(pca->regmap, PCA9685_MODE2, reg); - regmap_write(pca->regmap, PCA9685_MODE2, mode2); + /* Disable all LED ALLCALL and SUBx addresses to avoid bus collisions */ + regmap_read(pca->regmap, PCA9685_MODE1, ®); + reg &= ~(MODE1_ALLCALL | MODE1_SUB1 | MODE1_SUB2 | MODE1_SUB3); + regmap_write(pca->regmap, PCA9685_MODE1, reg); /* Clear all "full off" bits */ regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0); -- cgit v1.2.3