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From: Victor Duicu <victor.duicu@microchip.com> This patch implements ACPI support to Microchip pac1921. The driver can read shunt resistor value and label from ACPI table. Signed-off-by: Victor Duicu <victor.duicu@microchip.com> --- The patch was tested on minnowboard and sama5. Differences related to previous versions: 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 | 104 +++++++++++++++++++++++++++++++++----- 1 file changed, 90 insertions(+), 14 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index XXXXXXX..XXXXXXX 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -XXX,XX +XXX,XX @@ 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 +#define PAC1921_DSM_UUID "f7bb9932-86ee-4516-a236-7a7a742e55cb" + /* * Pre-computed scale factors for BUS voltage * format: IIO_VAL_INT_PLUS_NANO @@ -XXX,XX +XXX,XX @@ struct pac1921_priv { } scan; }; +static inline bool pac1921_shunt_is_invalid(u64 shunt_val) +{ + return (shunt_val == 0 || shunt_val > INT_MAX); +} + /* * Check if first integration after configuration update has completed. * @@ -XXX,XX +XXX,XX @@ 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) + rshunt_uohm = (u64)val * MICRO + val_fract; + if (pac1921_shunt_is_invalid(rshunt_uohm)) return -EINVAL; guard(mutex)(&priv->lock); - priv->rshunt_uohm = rshunt_uohm; + priv->rshunt_uohm = (u32)rshunt_uohm; pac1921_calc_current_scales(priv); @@ -XXX,XX +XXX,XX @@ 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 i2c_client *client, struct pac1921_priv *priv, + struct iio_dev *indio_dev) +{ + acpi_handle handle; + union acpi_object *rez; + guid_t guid; + char *label; + u64 temp; + + guid_parse(PAC1921_DSM_UUID, &guid); + handle = ACPI_HANDLE(&client->dev); + + rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1921_ACPI_GET_UOHMS_VALS, NULL); + if (!rez) + return dev_err_probe(&client->dev, -EINVAL, + "Could not read shunt from ACPI table\n"); + + temp = rez->package.elements[0].integer.value; + ACPI_FREE(rez); + + if (pac1921_shunt_is_invalid(temp)) + return dev_err_probe(&client->dev, -EINVAL, "Invalid shunt resistor\n"); + + priv->rshunt_uohm = temp; + pac1921_calc_current_scales(priv); + + rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1921_ACPI_GET_LABEL, NULL); + if (!rez) + return dev_err_probe(&client->dev, -EINVAL, + "Could not read label from ACPI table\n"); + + label = devm_kmemdup(&client->dev, rez->package.elements->string.pointer, + (size_t)rez->package.elements->string.length + 1, + GFP_KERNEL); + label[rez->package.elements->string.length] = '\0'; + indio_dev->label = label; + ACPI_FREE(rez); + + return 0; +} + +static int pac1921_parse_of_fw(struct i2c_client *client, struct pac1921_priv *priv) +{ + int ret; + struct device *dev = &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"); + + if (pac1921_shunt_is_invalid(priv->rshunt_uohm)) + return dev_err_probe(dev, -EINVAL, "Invalid shunt resistor: %u\n", + priv->rshunt_uohm); + + pac1921_calc_current_scales(priv); + + return 0; +} + static int pac1921_probe(struct i2c_client *client) { struct device *dev = &client->dev; @@ -XXX,XX +XXX,XX @@ 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) - 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", - priv->rshunt_uohm); - - pac1921_calc_current_scales(priv); + if (ACPI_HANDLE(&client->dev)) + ret = pac1921_match_acpi_device(client, priv, indio_dev); + else + ret = pac1921_parse_of_fw(client, priv); + if (ret < 0) + return dev_err_probe(&client->dev, ret, + "parameter parsing error\n"); priv->vdd = devm_regulator_get(dev, "vdd"); if (IS_ERR(priv->vdd)) @@ -XXX,XX +XXX,XX @@ 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: c3e9df514041ec6c46be83801b1891392f4522f7 -- 2.43.0
From: Victor Duicu <victor.duicu@microchip.com> This patch implements ACPI support to Microchip pac1921. The driver can read shunt resistor value and label from ACPI table. Signed-off-by: Victor Duicu <victor.duicu@microchip.com> --- The patch was tested on minnowboard and sama5. Differences related to previous versions: 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 | 95 +++++++++++++++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 9 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index XXXXXXX..XXXXXXX 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -XXX,XX +XXX,XX @@ 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 +#define PAC1921_DSM_UUID "f7bb9932-86ee-4516-a236-7a7a742e55cb" +/* The maximum accepted value of shunt_resistor in UOHMS <= INT_MAX */ +#define PAC1921_MAX_SHUNT_VALUE_OHMS 2147 + /* * Pre-computed scale factors for BUS voltage * format: IIO_VAL_INT_PLUS_NANO @@ -XXX,XX +XXX,XX @@ struct pac1921_priv { } scan; }; +static inline bool pac1921_shunt_is_invalid(u32 shunt_val) +{ + return shunt_val == 0 || shunt_val > INT_MAX; +} + /* * Check if first integration after configuration update has completed. * @@ -XXX,XX +XXX,XX @@ 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; @@ -XXX,XX +XXX,XX @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, if (ret) return ret; + /* This check is to ensure val * MICRO won't overflow */ + if (val < 0 || val > PAC1921_MAX_SHUNT_VALUE_OHMS) + return -EINVAL; + rshunt_uohm = val * MICRO + val_fract; - if (rshunt_uohm == 0 || rshunt_uohm > INT_MAX) + if (pac1921_shunt_is_invalid(rshunt_uohm)) return -EINVAL; guard(mutex)(&priv->lock); @@ -XXX,XX +XXX,XX @@ 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 *rez; + guid_t guid; + char *label; + struct pac1921_priv *priv = iio_priv(indio_dev); + struct device *dev = &priv->client->dev; + + guid_parse(PAC1921_DSM_UUID, &guid); + handle = ACPI_HANDLE(dev); + + rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1921_ACPI_GET_UOHMS_VALS, NULL); + if (!rez) + return dev_err_probe(dev, -EINVAL, + "Could not read shunt from ACPI table\n"); + + priv->rshunt_uohm = rez->package.elements[0].integer.value; + ACPI_FREE(rez); + + rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1921_ACPI_GET_LABEL, NULL); + if (!rez) + return dev_err_probe(dev, -EINVAL, + "Could not read label from ACPI table\n"); + + label = devm_kstrdup(dev, rez->package.elements->string.pointer, GFP_KERNEL); + if (!label) + return dev_err_probe(dev, -EINVAL, "Label is NULL\n"); + + indio_dev->label = label; + ACPI_FREE(rez); + + 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; @@ -XXX,XX +XXX,XX @@ 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 (ACPI_HANDLE(dev)) + 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 (pac1921_shunt_is_invalid(priv->rshunt_uohm)) + return dev_err_probe(dev, -EINVAL, "Invalid shunt resistor: %u\n", priv->rshunt_uohm); pac1921_calc_current_scales(priv); @@ -XXX,XX +XXX,XX @@ 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: e2687d0723257db5025a4cf8cefbd80bed1e2681 -- 2.43.0