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path: root/drivers/gpio/mcp23018.c
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Diffstat (limited to 'drivers/gpio/mcp23018.c')
-rw-r--r--drivers/gpio/mcp23018.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/gpio/mcp23018.c b/drivers/gpio/mcp23018.c
index 41cbfe087e..b4fbf296f8 100644
--- a/drivers/gpio/mcp23018.c
+++ b/drivers/gpio/mcp23018.c
@@ -18,14 +18,20 @@ enum {
CMD_GPIOB = 0x13,
};
-void mcp23018_init(uint8_t addr) {
+bool mcp23018_init(uint8_t slave_addr) {
static uint8_t s_init = 0;
- if (!s_init) {
+ uint8_t addr = SLAVE_TO_ADDR(slave_addr);
+ if (0 == s_init) {
i2c_init();
- wait_ms(1000);
+ wait_ms(100);
- s_init = 1;
+ // probe that the expander is actually connected by reading from it
+ uint8_t data = 0;
+ if (I2C_STATUS_SUCCESS == i2c_readReg(addr, 0, &data, sizeof(data), 150)) {
+ s_init = 1;
+ }
}
+ return (s_init > 0);
}
bool mcp23018_set_config(uint8_t slave_addr, mcp23018_port_t port, uint8_t conf) {