Implement the settling cycles encoding as specified in the AD5933 datasheet, Table 13 ("Number of Settling Times Cycles Register"). The previous logic did not correctly translate the user-requested effective cycle count into the required 9-bit base + 2-bit multiplier format (D10..D0) for values exceeding 511.

Clamp the user input for out_altvoltage0_settling_cycles to the maximum effective value of 2044 cycles (511 * 4x multiplier).

Fixes: f94aa354d676 ("iio: impedance-analyzer: New driver for AD5933/4 Impedance Converter, Network Analyzer") Cc: stable@vger.kernel.org Signed-off-by: Gabriel Shahrouzi gshahrouzi@gmail.com --- Changes in v2: - Fix spacing in comment around '+'. - Define mask and values for settling cycle multipliers. --- .../staging/iio/impedance-analyzer/ad5933.c | 23 +++++++++++++------ 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c index d5544fc2fe989..3c301a8ebd2ab 100644 --- a/drivers/staging/iio/impedance-analyzer/ad5933.c +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c @@ -28,7 +28,7 @@ #define AD5933_REG_FREQ_START 0x82 /* R/W, 3 bytes */ #define AD5933_REG_FREQ_INC 0x85 /* R/W, 3 bytes */ #define AD5933_REG_INC_NUM 0x88 /* R/W, 2 bytes, 9 bit */ -#define AD5933_REG_SETTLING_CYCLES 0x8A /* R/W, 2 bytes */ +#define AD5933_REG_SETTLING_CYCLES 0x8A /* R/W, 2 bytes, 11 + 2 bit */ #define AD5933_REG_STATUS 0x8F /* R, 1 byte */ #define AD5933_REG_TEMP_DATA 0x92 /* R, 2 bytes*/ #define AD5933_REG_REAL_DATA 0x94 /* R, 2 bytes*/ @@ -71,6 +71,8 @@ #define AD5933_INT_OSC_FREQ_Hz 16776000 #define AD5933_MAX_OUTPUT_FREQ_Hz 100000 #define AD5933_MAX_RETRIES 100 +#define AD5933_MAX_FREQ_POINTS 511 +#define AD5933_MAX_SETTLING_CYCLES 2044 /* 511 * 4 */

#define AD5933_OUT_RANGE 1 #define AD5933_OUT_RANGE_AVAIL 2 @@ -82,6 +84,12 @@ #define AD5933_POLL_TIME_ms 10 #define AD5933_INIT_EXCITATION_TIME_ms 100

+/* Settling cycles multiplier bits D10, D9 */ +#define AD5933_SETTLE_MUL_MASK (BIT(10) | BIT(9)) +#define AD5933_SETTLE_MUL_1X 0 +#define AD5933_SETTLE_MUL_2X BIT(9) +#define AD5933_SETTLE_MUL_4X (BIT(10) | BIT(9)) + struct ad5933_state { struct i2c_client *client; struct clk *mclk; @@ -411,14 +419,15 @@ static ssize_t ad5933_store(struct device *dev, ret = ad5933_cmd(st, 0); break; case AD5933_OUT_SETTLING_CYCLES: - val = clamp(val, (u16)0, (u16)0x7FF); + val = clamp(val, (u16)0, (u16)AD5933_MAX_SETTLING_CYCLES); st->settling_cycles = val;

- /* 2x, 4x handling, see datasheet */ + /* Encode value for register: D10..D0 */ + /* Datasheet Table 13: If cycles > 1022 -> val/4, set bits D10=1, D9=1 */ if (val > 1022) - val = (val >> 2) | (3 << 9); - else if (val > 511) - val = (val >> 1) | BIT(9); + val = (val >> 2) | AD5933_SETTLE_MUL_4X; + else if (val > 511) /* Datasheet: If cycles > 511 -> val/2, set bit D9=1 */ + val = (val >> 1) | AD5933_SETTLE_MUL_2X;

dat = cpu_to_be16(val); ret = ad5933_i2c_write(st->client, @@ -426,7 +435,7 @@ static ssize_t ad5933_store(struct device *dev, 2, (u8 *)&dat); break; case AD5933_FREQ_POINTS: - val = clamp(val, (u16)0, (u16)511); + val = clamp(val, (u16)0, (u16)AD5933_MAX_FREQ_POINTS); st->freq_points = val;

dat = cpu_to_be16(val);