diff options
Diffstat (limited to 'drivers/mfd/axp20x.c')
| -rw-r--r-- | drivers/mfd/axp20x.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c index 20b95af9a217..25115fe2acdf 100644 --- a/drivers/mfd/axp20x.c +++ b/drivers/mfd/axp20x.c @@ -31,6 +31,8 @@ #define AXP20X_OFF 0x80 +#define AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE BIT(4) + static const char * const axp20x_model_names[] = { "AXP152", "AXP202", @@ -861,6 +863,30 @@ int axp20x_device_probe(struct axp20x_dev *axp20x) { int ret; + /* + * The AXP806 supports either master/standalone or slave mode. + * Slave mode allows sharing the serial bus, even with multiple + * AXP806 which all have the same hardware address. + * + * This is done with extra "serial interface address extension", + * or AXP806_BUS_ADDR_EXT, and "register address extension", or + * AXP806_REG_ADDR_EXT, registers. The former is read-only, with + * 1 bit customizable at the factory, and 1 bit depending on the + * state of an external pin. The latter is writable. The device + * will only respond to operations to its other registers when + * the these device addressing bits (in the upper 4 bits of the + * registers) match. + * + * Since we only support an AXP806 chained to an AXP809 in slave + * mode, and there isn't any existing hardware which uses AXP806 + * in master mode, or has 2 AXP806s in the same system, we can + * just program the register address extension to the slave mode + * address. + */ + if (axp20x->variant == AXP806_ID) + regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT, + AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE); + ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq, IRQF_ONESHOT | IRQF_SHARED | axp20x->irq_flags, -1, axp20x->regmap_irq_chip, &axp20x->regmap_irqc); |