diff options
Diffstat (limited to 'drivers/iio/accel/adxl355_core.c')
| -rw-r--r-- | drivers/iio/accel/adxl355_core.c | 44 |
1 files changed, 39 insertions, 5 deletions
diff --git a/drivers/iio/accel/adxl355_core.c b/drivers/iio/accel/adxl355_core.c index 2e00fd51b4d5..5fc7f814b907 100644 --- a/drivers/iio/accel/adxl355_core.c +++ b/drivers/iio/accel/adxl355_core.c @@ -56,6 +56,8 @@ #define ADXL355_POWER_CTL_DRDY_MSK BIT(2) #define ADXL355_SELF_TEST_REG 0x2E #define ADXL355_RESET_REG 0x2F +#define ADXL355_BASE_ADDR_SHADOW_REG 0x50 +#define ADXL355_SHADOW_REG_COUNT 5 #define ADXL355_DEVID_AD_VAL 0xAD #define ADXL355_DEVID_MST_VAL 0x1D @@ -294,7 +296,12 @@ static void adxl355_fill_3db_frequency_table(struct adxl355_data *data) static int adxl355_setup(struct adxl355_data *data) { unsigned int regval; + int retries = 5; /* the number is chosen based on empirical reasons */ int ret; + u8 *shadow_regs __free(kfree) = kzalloc(ADXL355_SHADOW_REG_COUNT, GFP_KERNEL); + + if (!shadow_regs) + return -ENOMEM; ret = regmap_read(data->regmap, ADXL355_DEVID_AD_REG, ®val); if (ret) @@ -321,14 +328,41 @@ static int adxl355_setup(struct adxl355_data *data) if (regval != ADXL355_PARTID_VAL) dev_warn(data->dev, "Invalid DEV ID 0x%02x\n", regval); - /* - * Perform a software reset to make sure the device is in a consistent - * state after start-up. - */ - ret = regmap_write(data->regmap, ADXL355_RESET_REG, ADXL355_RESET_CODE); + /* Read shadow registers to be compared after reset */ + ret = regmap_bulk_read(data->regmap, + ADXL355_BASE_ADDR_SHADOW_REG, + shadow_regs, ADXL355_SHADOW_REG_COUNT); if (ret) return ret; + do { + if (--retries == 0) { + dev_err(data->dev, "Shadow registers mismatch\n"); + return -EIO; + } + + /* + * Perform a software reset to make sure the device is in a consistent + * state after start-up. + */ + ret = regmap_write(data->regmap, ADXL355_RESET_REG, + ADXL355_RESET_CODE); + if (ret) + return ret; + + /* Wait at least 5ms after software reset */ + usleep_range(5000, 10000); + + /* Read shadow registers for comparison */ + ret = regmap_bulk_read(data->regmap, + ADXL355_BASE_ADDR_SHADOW_REG, + data->buffer.buf, + ADXL355_SHADOW_REG_COUNT); + if (ret) + return ret; + } while (memcmp(shadow_regs, data->buffer.buf, + ADXL355_SHADOW_REG_COUNT)); + ret = regmap_update_bits(data->regmap, ADXL355_POWER_CTL_REG, ADXL355_POWER_CTL_DRDY_MSK, FIELD_PREP(ADXL355_POWER_CTL_DRDY_MSK, 1)); |