diff options
Diffstat (limited to 'drivers/staging/iio/light/isl29018.c')
| -rw-r--r-- | drivers/staging/iio/light/isl29018.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c index 426b6af70807..da5bb33a66c1 100644 --- a/drivers/staging/iio/light/isl29018.c +++ b/drivers/staging/iio/light/isl29018.c @@ -53,6 +53,10 @@ #define ISL29018_REG_ADD_DATA_MSB 0x03 #define ISL29018_MAX_REGS ISL29018_REG_ADD_DATA_MSB +#define ISL29018_REG_TEST 0x08 +#define ISL29018_TEST_SHIFT 0 +#define ISL29018_TEST_MASK (0xFF << ISL29018_TEST_SHIFT) + struct isl29018_chip { struct i2c_client *client; struct mutex lock; @@ -457,6 +461,48 @@ static int isl29018_chip_init(struct i2c_client *client) memset(chip->reg_cache, 0, sizeof(chip->reg_cache)); + /* Code added per Intersil Application Note 1534: + * When VDD sinks to approximately 1.8V or below, some of + * the part's registers may change their state. When VDD + * recovers to 2.25V (or greater), the part may thus be in an + * unknown mode of operation. The user can return the part to + * a known mode of operation either by (a) setting VDD = 0V for + * 1 second or more and then powering back up with a slew rate + * of 0.5V/ms or greater, or (b) via I2C disable all ALS/PROX + * conversions, clear the test registers, and then rewrite all + * registers to the desired values. + * ... + * FOR ISL29011, ISL29018, ISL29021, ISL29023 + * 1. Write 0x00 to register 0x08 (TEST) + * 2. Write 0x00 to register 0x00 (CMD1) + * 3. Rewrite all registers to the desired values + * + * ISL29018 Data Sheet (FN6619.1, Feb 11, 2010) essentially says + * the same thing EXCEPT the data sheet asks for a 1ms delay after + * writing the CMD1 register. + */ + status = isl29018_write_data(client, ISL29018_REG_TEST, 0, + ISL29018_TEST_MASK, ISL29018_TEST_SHIFT); + if (status < 0) { + dev_err(&client->dev, "Failed to clear isl29018 TEST reg." + "(%d)\n", status); + return status; + } + + /* See Intersil AN1534 comments above. + * "Operating Mode" (COMMAND1) register is reprogrammed when + * data is read from the device. + */ + status = isl29018_write_data(client, ISL29018_REG_ADD_COMMAND1, 0, + 0xff, 0); + if (status < 0) { + dev_err(&client->dev, "Failed to clear isl29018 CMD1 reg." + "(%d)\n", status); + return status; + } + + msleep(1); /* per data sheet, page 10 */ + /* set defaults */ status = isl29018_set_range(client, chip->range, &new_range); if (status < 0) { |