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iio: dac: mcp47feb02: Fix Vref validation [1-999] case

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Store reference voltages in uV instead of mV to avoid invalid error code
in dev_err_probe() call. Vref variables store the actual value returned by
devm_regulator_get_enable_read_voltage() function instead of the results of
dividing it by MILLI. The corner case [1-999] divided by MILLI of the
voltage reference variable value would become 0 is covered too.

Fixes: bf394cc803 ("iio: dac: adding support for Microchip MCP47FEB02")
Link: https://lore.kernel.org/all/aYXvP5FLA5BvkoVX@stanley.mountain/
Signed-off-by: Ariana Lazar <ariana.lazar@microchip.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Ariana Lazar 2026-03-10 13:56:44 +02:00 committed by Jonathan Cameron
parent c05a87d9ec
commit dd154646d2
1 changed files with 22 additions and 27 deletions
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49
drivers/iio/dac/mcp47feb02.c
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@ -65,7 +65,7 @@
#define MCP47FEB02_MAX_SCALES_CH 3 #define MCP47FEB02_MAX_SCALES_CH 3
#define MCP47FEB02_DAC_WIPER_UNLOCKED 0 #define MCP47FEB02_DAC_WIPER_UNLOCKED 0
#define MCP47FEB02_NORMAL_OPERATION 0 #define MCP47FEB02_NORMAL_OPERATION 0
#define MCP47FEB02_INTERNAL_BAND_GAP_mV 2440 #define MCP47FEB02_INTERNAL_BAND_GAP_uV 2440000
#define NV_DAC_ADDR_OFFSET 0x10 #define NV_DAC_ADDR_OFFSET 0x10
enum mcp47feb02_vref_mode { enum mcp47feb02_vref_mode {
@ -697,44 +697,40 @@ static const struct iio_chan_spec mcp47febxx_ch_template = {
}; };
static void mcp47feb02_init_scale(struct mcp47feb02_data *data, enum mcp47feb02_scale scale, static void mcp47feb02_init_scale(struct mcp47feb02_data *data, enum mcp47feb02_scale scale,
int vref_mV, int scale_avail[]) int vref_uV, int scale_avail[])
{ {
u32 value_micro, value_int; u32 value_micro, value_int;
u64 tmp; u64 tmp;
/* vref_mV should not be negative */ /* vref_uV should not be negative */
tmp = (u64)vref_mV * MICRO >> data->chip_features->resolution; tmp = (u64)vref_uV * MILLI >> data->chip_features->resolution;
value_int = div_u64_rem(tmp, MICRO, &value_micro); value_int = div_u64_rem(tmp, MICRO, &value_micro);
scale_avail[scale * 2] = value_int; scale_avail[scale * 2] = value_int;
scale_avail[scale * 2 + 1] = value_micro; scale_avail[scale * 2 + 1] = value_micro;
} }
static int mcp47feb02_init_scales_avail(struct mcp47feb02_data *data, int vdd_mV, static int mcp47feb02_init_scales_avail(struct mcp47feb02_data *data, int vdd_uV,
int vref_mV, int vref1_mV) int vref_uV, int vref1_uV)
{ {
struct device *dev = regmap_get_device(data->regmap);
int tmp_vref; int tmp_vref;
mcp47feb02_init_scale(data, MCP47FEB02_SCALE_VDD, vdd_mV, data->scale); mcp47feb02_init_scale(data, MCP47FEB02_SCALE_VDD, vdd_uV, data->scale);
if (data->use_vref) if (data->use_vref)
tmp_vref = vref_mV; tmp_vref = vref_uV;
else else
tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_mV; tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_uV;
mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X1, tmp_vref, data->scale); mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X1, tmp_vref, data->scale);
mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X2, tmp_vref * 2, data->scale); mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X2, tmp_vref * 2, data->scale);
if (data->phys_channels >= 4) { if (data->phys_channels >= 4) {
mcp47feb02_init_scale(data, MCP47FEB02_SCALE_VDD, vdd_mV, data->scale_1); mcp47feb02_init_scale(data, MCP47FEB02_SCALE_VDD, vdd_uV, data->scale_1);
if (data->use_vref1 && vref1_mV <= 0)
return dev_err_probe(dev, vref1_mV, "Invalid voltage for Vref1\n");
if (data->use_vref1) if (data->use_vref1)
tmp_vref = vref1_mV; tmp_vref = vref1_uV;
else else
tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_mV; tmp_vref = MCP47FEB02_INTERNAL_BAND_GAP_uV;
mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X1, mcp47feb02_init_scale(data, MCP47FEB02_SCALE_GAIN_X1,
tmp_vref, data->scale_1); tmp_vref, data->scale_1);
@ -1078,8 +1074,8 @@ static int mcp47feb02_init_ctrl_regs(struct mcp47feb02_data *data)
return 0; return 0;
} }
static int mcp47feb02_init_ch_scales(struct mcp47feb02_data *data, int vdd_mV, static int mcp47feb02_init_ch_scales(struct mcp47feb02_data *data, int vdd_uV,
int vref_mV, int vref1_mV) int vref_uV, int vref1_uV)
{ {
unsigned int i; unsigned int i;
@ -1087,7 +1083,7 @@ static int mcp47feb02_init_ch_scales(struct mcp47feb02_data *data, int vdd_mV,
struct device *dev = regmap_get_device(data->regmap); struct device *dev = regmap_get_device(data->regmap);
int ret; int ret;
ret = mcp47feb02_init_scales_avail(data, vdd_mV, vref_mV, vref1_mV); ret = mcp47feb02_init_scales_avail(data, vdd_uV, vref_uV, vref1_uV);
if (ret) if (ret)
return dev_err_probe(dev, ret, "failed to init scales for ch %u\n", i); return dev_err_probe(dev, ret, "failed to init scales for ch %u\n", i);
} }
@ -1101,10 +1097,7 @@ static int mcp47feb02_probe(struct i2c_client *client)
struct device *dev = &client->dev; struct device *dev = &client->dev;
struct mcp47feb02_data *data; struct mcp47feb02_data *data;
struct iio_dev *indio_dev; struct iio_dev *indio_dev;
int vref1_mV = 0; int vref1_uV, vref_uV, vdd_uV, ret;
int vref_mV = 0;
int vdd_mV;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev) if (!indio_dev)
@ -1141,13 +1134,14 @@ static int mcp47feb02_probe(struct i2c_client *client)
if (ret < 0) if (ret < 0)
return ret; return ret;
vdd_mV = ret / MILLI; vdd_uV = ret;
ret = devm_regulator_get_enable_read_voltage(dev, "vref"); ret = devm_regulator_get_enable_read_voltage(dev, "vref");
if (ret > 0) { if (ret > 0) {
vref_mV = ret / MILLI; vref_uV = ret;
data->use_vref = true; data->use_vref = true;
} else { } else {
vref_uV = 0;
dev_dbg(dev, "using internal band gap as voltage reference.\n"); dev_dbg(dev, "using internal band gap as voltage reference.\n");
dev_dbg(dev, "Vref is unavailable.\n"); dev_dbg(dev, "Vref is unavailable.\n");
} }
@ -1155,9 +1149,10 @@ static int mcp47feb02_probe(struct i2c_client *client)
if (chip_features->have_ext_vref1) { if (chip_features->have_ext_vref1) {
ret = devm_regulator_get_enable_read_voltage(dev, "vref1"); ret = devm_regulator_get_enable_read_voltage(dev, "vref1");
if (ret > 0) { if (ret > 0) {
vref1_mV = ret / MILLI; vref1_uV = ret;
data->use_vref1 = true; data->use_vref1 = true;
} else { } else {
vref1_uV = 0;
dev_dbg(dev, "using internal band gap as voltage reference 1.\n"); dev_dbg(dev, "using internal band gap as voltage reference 1.\n");
dev_dbg(dev, "Vref1 is unavailable.\n"); dev_dbg(dev, "Vref1 is unavailable.\n");
} }
@ -1167,7 +1162,7 @@ static int mcp47feb02_probe(struct i2c_client *client)
if (ret) if (ret)
return dev_err_probe(dev, ret, "Error initialising vref register\n"); return dev_err_probe(dev, ret, "Error initialising vref register\n");
ret = mcp47feb02_init_ch_scales(data, vdd_mV, vref_mV, vref1_mV); ret = mcp47feb02_init_ch_scales(data, vdd_uV, vref_uV, vref1_uV);
if (ret) if (ret)
return ret; return ret;