Commit bce54366 authored by David Jander's avatar David Jander Committed by Thierry Reding
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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: default avatarDavid Jander <david@protonic.nl>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent e1057a8d

drivers/pwm/pwm-pca9685.c

+16 −7
Original line number Diff line number Diff line
@@ -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, &reg);



	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);

	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);

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