| Message ID | 20241115100756.8923-1-victor.duicu@microchip.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v12] iio: adc: pac1921: Add ACPI support to Microchip pac1921 | expand |
Hi Victor, Below just a few very minor styling points. Sorry I didn't notice them before. However, I am also fine with this version as it is. Acked-by: Matteo Martelli <matteomartelli3@gmail.com> On Fri, 15 Nov 2024 12:07:56 +0200, <victor.duicu@microchip.com> wrote: > From: Victor Duicu <victor.duicu@microchip.com> > > This patch implements ACPI support to Microchip pac1921. > The driver can read the shunt resistor value and label from the ACPI table. > > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Signed-off-by: Victor Duicu <victor.duicu@microchip.com> > --- > > The patch was tested on minnowboard and sama5. > > Differences related to previous versions: > v12: > - in pac1921_match_acpi_device reformat the instructions that > were over 80 characters width. > - remove PAC1921_MAX_SHUNT_VALUE_uOHMS. Now the maximum acceptable value > of shunt resistor is INT_MAX. In pac1921_write_shunt_resistor > change the shunt check to respect the new limit and to avoid > overflow in val * MICRO. > > v11: > - credit Andy Shevchenko for code review. > > v10: > - fix coding style mistakes. > - add UL to PAC1921_MAX_SHUNT_VALUE_uOHMS. > - edit comment in pac1921_write_shunt_resistor. > - in pac1921_probe use is_acpi_device_node instead of > ACPI_HANDLE. > > v9: > - put limits.h in sorted order. > - remove guid_parse and implement GUID_INIT. > - remove pac1921_shunt_is_valid. > - change maximum acceptable value of shunt resistor to 2146.999999. > This change was made so the readings for dt and ACPI share > the same range. > With this value the maximum current that can be read is > 0.1V / 2146.999999 = 46.576 uA > If we use INT_MAX the maximum current is > 0.1V / 2147.483647 = 46.566 uA > The relative error between the two is 0.0214, so it is > small enough to allow for code simplicity. > A shunt value over a few hundred Ohms is quite unusual. > > v8: > - fix multiple coding style errors. > - in pac1921_match_acpi_device change error type to ENOMEM > at label is NULL branch. > - in pac1921_match_acpi_device when reading label, > change accesing method of string. > - change name of PAC1921_ACPI_GET_UOHMS_VALS to > PAC1921_ACPI_GET_uOHMS_VALS. > - add limits.h in include list. > - change integer constant in PAC1921_MAX_SHUNT_VALUE_OHMS > to INT_MAX / MICRO. > - change pac1921_shunt_is_invalid to pac1921_shunt_is_valid. > - in pac1921_match_acpi_device change name of variable rez to status. > > v7: > - in pac1921_shunt_is_invalid remove brackets in return. > - in pac1921_match_acpi_device and pac1921_parse_of_fw move checking of > shunt value and scale calculation to pac1921_probe. > - in pac1921_match_acpi_device change devm_kmemdup to devm_kstrdup > and add label check for NULL. > - in pac1921_match_acpi_device and pac1921_parse_of_fw remove unnecessary > entry arguments. Now indio_dev is the only entry argument. > - in pac1921_probe, pac1921_match_acpi_device and pac1921_parse_of_fw > standardised structure accesing. > > v6: > - set maximum acceptable value of shunt resistor to INT_MAX UOHMS > in devicetree, ACPI table and user input. > - in pac1921_match_acpi_device remove temp variable. > > v5: > - set maximum acceptable value of shunt resistor to 2KOHM in devicetree, > ACPI table and user input. The chosen value is lesser than INT_MAX, > which is about 2.1KOHM. > - in pac1921_match_acpi_device and pac1921_parse_of_fw change to only > read 32b values for resistor shunt. > > v4: > - change name of pac1921_shunt_is_valid to pac1921_shunt_is_invalid. > - fix coding style. > - in pac1921_parse_of_fw change back to device_property_read_u32. > > v3: > - simplify and make inline function pac1921_shunt_is_valid. Make argument u64. > - fix link to DSM documentation. > - in pac1921_match_acpi_device and pac1921_parse_of_fw, the shunt value is > read as u64. > - in pac1921_parse_of_fw remove code for reading label value from > devicetree. > - in pac1921_write_shunt_resistor cast the multiply result to u64 in order > to fix overflow. > > v2: > - remove name variable from priv. Driver reads label attribute with > sysfs. > - define pac1921_shunt_is_valid function. > - move default assignments in pac1921_probe to original position. > - roll back coding style changes. > - add documentation for DSM(the linked document was used as reference). > - remove acpi_match_device in pac1921_match_acpi_device. > - remove unnecessary null assignment and comment. > - change name of function pac1921_match_of_device to > pac1921_parse_of_fw. > > v1: > - initial version for review. > > drivers/iio/adc/pac1921.c | 100 ++++++++++++++++++++++++++++++++++---- > 1 file changed, 90 insertions(+), 10 deletions(-) > > diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c > index b0f6727cfe38..a78ae34057a1 100644 > --- a/drivers/iio/adc/pac1921.c > +++ b/drivers/iio/adc/pac1921.c > @@ -12,6 +12,7 @@ > #include <linux/iio/iio.h> > #include <linux/iio/trigger_consumer.h> > #include <linux/iio/triggered_buffer.h> > +#include <linux/limits.h> > #include <linux/regmap.h> > #include <linux/units.h> > > @@ -67,6 +68,14 @@ enum pac1921_mxsl { > #define PAC1921_DEFAULT_DI_GAIN 0 /* 2^(value): 1x gain (HW default) */ > #define PAC1921_DEFAULT_NUM_SAMPLES 0 /* 2^(value): 1 sample (HW default) */ > > +#define PAC1921_ACPI_GET_uOHMS_VALS 0 > +#define PAC1921_ACPI_GET_LABEL 1 > + > +/* f7bb9932-86ee-4516-a236-7a7a742e55cb */ > +static const guid_t pac1921_guid = > + GUID_INIT(0xf7bb9932, 0x86ee, 0x4516, 0xa2, > + 0x36, 0x7a, 0x7a, 0x74, 0x2e, 0x55, 0xcb); > + > /* > * Pre-computed scale factors for BUS voltage > * format: IIO_VAL_INT_PLUS_NANO > @@ -782,7 +791,7 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, > const char *buf, size_t len) > { > struct pac1921_priv *priv = iio_priv(indio_dev); > - u64 rshunt_uohm; > + u32 rshunt_uohm; > int val, val_fract; > int ret; > > @@ -793,10 +802,17 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, > if (ret) > return ret; > > - rshunt_uohm = val * MICRO + val_fract; > - if (rshunt_uohm == 0 || rshunt_uohm > INT_MAX) > + /* > + * This check validates the shunt is not zero and does not surpass > + * INT_MAX. The check is done before calculating in order to avoid > + * val * MICRO overflowing. > + */ > + if ((!val && !val_fract) || (val > INT_MAX / MICRO) || > + ((val == INT_MAX / MICRO) && (val_fract > INT_MAX % MICRO))) > return -EINVAL; Can the unnecessary parenthesis be removed? if ((!val && !val_fract) || (val > INT_MAX / MICRO) || ^.....................^ ((val == INT_MAX / MICRO) && (val_fract > INT_MAX % MICRO))) ^......................^ ^...........................^ > > + rshunt_uohm = val * MICRO + val_fract; > + > guard(mutex)(&priv->lock); > > priv->rshunt_uohm = rshunt_uohm; > @@ -1151,6 +1167,61 @@ static void pac1921_regulator_disable(void *data) > regulator_disable(regulator); > } > > +/* > + * Documentation related to the ACPI device definition > + * https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ApplicationNotes/ApplicationNotes/PAC193X-Integration-Notes-for-Microsoft-Windows-10-and-Windows-11-Driver-Support-DS00002534.pdf > + */ > +static int pac1921_match_acpi_device(struct iio_dev *indio_dev) > +{ > + acpi_handle handle; > + union acpi_object *status; > + char *label; > + struct pac1921_priv *priv = iio_priv(indio_dev); > + struct device *dev = &priv->client->dev; > + > + handle = ACPI_HANDLE(dev); > + > + status = acpi_evaluate_dsm(handle, &pac1921_guid, 1, > + PAC1921_ACPI_GET_uOHMS_VALS, NULL); > + if (!status) > + return dev_err_probe(dev, -EINVAL, > + "Could not read shunt from ACPI table\n"); > + > + priv->rshunt_uohm = status->package.elements[0].integer.value; > + ACPI_FREE(status); > + > + status = acpi_evaluate_dsm(handle, &pac1921_guid, 1, > + PAC1921_ACPI_GET_LABEL, NULL); > + if (!status) > + return dev_err_probe(dev, -EINVAL, > + "Could not read label from ACPI table\n"); > + > + label = devm_kstrdup(dev, status->package.elements[0].string.pointer, > + GFP_KERNEL); > + if (!label) > + return -ENOMEM; > + > + indio_dev->label = label; > + ACPI_FREE(status); > + > + return 0; > +} > + > +static int pac1921_parse_of_fw(struct iio_dev *indio_dev) > +{ > + int ret; > + struct pac1921_priv *priv = iio_priv(indio_dev); > + struct device *dev = &priv->client->dev; > + > + ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", > + &priv->rshunt_uohm); > + if (ret) > + return dev_err_probe(dev, ret, > + "Cannot read shunt resistor property\n"); > + > + return 0; > +} > + > static int pac1921_probe(struct i2c_client *client) > { > struct device *dev = &client->dev; > @@ -1179,14 +1250,16 @@ static int pac1921_probe(struct i2c_client *client) > priv->di_gain = PAC1921_DEFAULT_DI_GAIN; > priv->n_samples = PAC1921_DEFAULT_NUM_SAMPLES; > > - ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", > - &priv->rshunt_uohm); > - if (ret) > + if (is_acpi_device_node(dev->fwnode)) > + ret = pac1921_match_acpi_device(indio_dev); > + else > + ret = pac1921_parse_of_fw(indio_dev); > + if (ret < 0) For consistency: if (ret) instead of if (ret < 0) > return dev_err_probe(dev, ret, > - "Cannot read shunt resistor property\n"); > - if (priv->rshunt_uohm == 0 || priv->rshunt_uohm > INT_MAX) > - return dev_err_probe(dev, -EINVAL, > - "Invalid shunt resistor: %u\n", > + "Parameter parsing error\n"); > + > + if (!priv->rshunt_uohm || priv->rshunt_uohm > INT_MAX) > + return dev_err_probe(dev, -EINVAL, "Invalid shunt resistor: %u\n", The error string in a new line to keep it 80 char wide. > priv->rshunt_uohm); > > pac1921_calc_current_scales(priv); > @@ -1246,11 +1319,18 @@ static const struct of_device_id pac1921_of_match[] = { > }; > MODULE_DEVICE_TABLE(of, pac1921_of_match); > > +static const struct acpi_device_id pac1921_acpi_match[] = { > + { "MCHP1921" }, > + { } > +}; > +MODULE_DEVICE_TABLE(acpi, pac1921_acpi_match); > + > static struct i2c_driver pac1921_driver = { > .driver = { > .name = "pac1921", > .pm = pm_sleep_ptr(&pac1921_pm_ops), > .of_match_table = pac1921_of_match, > + .acpi_match_table = pac1921_acpi_match, > }, > .probe = pac1921_probe, > .id_table = pac1921_id, > > base-commit: 20fd1383cd616d61b2a79967da1221dc6cfb8430 > -- > 2.43.0 > Thanks, Matteo Martelli
diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index b0f6727cfe38..a78ae34057a1 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -12,6 +12,7 @@ #include <linux/iio/iio.h> #include <linux/iio/trigger_consumer.h> #include <linux/iio/triggered_buffer.h> +#include <linux/limits.h> #include <linux/regmap.h> #include <linux/units.h> @@ -67,6 +68,14 @@ enum pac1921_mxsl { #define PAC1921_DEFAULT_DI_GAIN 0 /* 2^(value): 1x gain (HW default) */ #define PAC1921_DEFAULT_NUM_SAMPLES 0 /* 2^(value): 1 sample (HW default) */ +#define PAC1921_ACPI_GET_uOHMS_VALS 0 +#define PAC1921_ACPI_GET_LABEL 1 + +/* f7bb9932-86ee-4516-a236-7a7a742e55cb */ +static const guid_t pac1921_guid = + GUID_INIT(0xf7bb9932, 0x86ee, 0x4516, 0xa2, + 0x36, 0x7a, 0x7a, 0x74, 0x2e, 0x55, 0xcb); + /* * Pre-computed scale factors for BUS voltage * format: IIO_VAL_INT_PLUS_NANO @@ -782,7 +791,7 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, const char *buf, size_t len) { struct pac1921_priv *priv = iio_priv(indio_dev); - u64 rshunt_uohm; + u32 rshunt_uohm; int val, val_fract; int ret; @@ -793,10 +802,17 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, if (ret) return ret; - rshunt_uohm = val * MICRO + val_fract; - if (rshunt_uohm == 0 || rshunt_uohm > INT_MAX) + /* + * This check validates the shunt is not zero and does not surpass + * INT_MAX. The check is done before calculating in order to avoid + * val * MICRO overflowing. + */ + if ((!val && !val_fract) || (val > INT_MAX / MICRO) || + ((val == INT_MAX / MICRO) && (val_fract > INT_MAX % MICRO))) return -EINVAL; + rshunt_uohm = val * MICRO + val_fract; + guard(mutex)(&priv->lock); priv->rshunt_uohm = rshunt_uohm; @@ -1151,6 +1167,61 @@ static void pac1921_regulator_disable(void *data) regulator_disable(regulator); } +/* + * Documentation related to the ACPI device definition + * https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ApplicationNotes/ApplicationNotes/PAC193X-Integration-Notes-for-Microsoft-Windows-10-and-Windows-11-Driver-Support-DS00002534.pdf + */ +static int pac1921_match_acpi_device(struct iio_dev *indio_dev) +{ + acpi_handle handle; + union acpi_object *status; + char *label; + struct pac1921_priv *priv = iio_priv(indio_dev); + struct device *dev = &priv->client->dev; + + handle = ACPI_HANDLE(dev); + + status = acpi_evaluate_dsm(handle, &pac1921_guid, 1, + PAC1921_ACPI_GET_uOHMS_VALS, NULL); + if (!status) + return dev_err_probe(dev, -EINVAL, + "Could not read shunt from ACPI table\n"); + + priv->rshunt_uohm = status->package.elements[0].integer.value; + ACPI_FREE(status); + + status = acpi_evaluate_dsm(handle, &pac1921_guid, 1, + PAC1921_ACPI_GET_LABEL, NULL); + if (!status) + return dev_err_probe(dev, -EINVAL, + "Could not read label from ACPI table\n"); + + label = devm_kstrdup(dev, status->package.elements[0].string.pointer, + GFP_KERNEL); + if (!label) + return -ENOMEM; + + indio_dev->label = label; + ACPI_FREE(status); + + return 0; +} + +static int pac1921_parse_of_fw(struct iio_dev *indio_dev) +{ + int ret; + struct pac1921_priv *priv = iio_priv(indio_dev); + struct device *dev = &priv->client->dev; + + ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", + &priv->rshunt_uohm); + if (ret) + return dev_err_probe(dev, ret, + "Cannot read shunt resistor property\n"); + + return 0; +} + static int pac1921_probe(struct i2c_client *client) { struct device *dev = &client->dev; @@ -1179,14 +1250,16 @@ static int pac1921_probe(struct i2c_client *client) priv->di_gain = PAC1921_DEFAULT_DI_GAIN; priv->n_samples = PAC1921_DEFAULT_NUM_SAMPLES; - ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", - &priv->rshunt_uohm); - if (ret) + if (is_acpi_device_node(dev->fwnode)) + ret = pac1921_match_acpi_device(indio_dev); + else + ret = pac1921_parse_of_fw(indio_dev); + if (ret < 0) return dev_err_probe(dev, ret, - "Cannot read shunt resistor property\n"); - if (priv->rshunt_uohm == 0 || priv->rshunt_uohm > INT_MAX) - return dev_err_probe(dev, -EINVAL, - "Invalid shunt resistor: %u\n", + "Parameter parsing error\n"); + + if (!priv->rshunt_uohm || priv->rshunt_uohm > INT_MAX) + return dev_err_probe(dev, -EINVAL, "Invalid shunt resistor: %u\n", priv->rshunt_uohm); pac1921_calc_current_scales(priv); @@ -1246,11 +1319,18 @@ static const struct of_device_id pac1921_of_match[] = { }; MODULE_DEVICE_TABLE(of, pac1921_of_match); +static const struct acpi_device_id pac1921_acpi_match[] = { + { "MCHP1921" }, + { } +}; +MODULE_DEVICE_TABLE(acpi, pac1921_acpi_match); + static struct i2c_driver pac1921_driver = { .driver = { .name = "pac1921", .pm = pm_sleep_ptr(&pac1921_pm_ops), .of_match_table = pac1921_of_match, + .acpi_match_table = pac1921_acpi_match, }, .probe = pac1921_probe, .id_table = pac1921_id,