From patchwork Fri Nov 8 08:50:12 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: victor.duicu@microchip.com X-Patchwork-Id: 13867759 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 82C291494D4; Fri, 8 Nov 2024 08:52:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=68.232.154.123 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731055926; cv=none; b=iN5n3umsBj30ZzwNaYCB/oTCxdIAJvRUZezVg+7J6Suc6hZd7UnEWkd2zV4OWUDKnut1QUGgyzmfLMr1Jc192VWNlsTlzK5X9l1dnACjuflqNfd7/XuzR2TLcRZubvWGGdZtRnr2T7mAmz56lNC0wgTZlPBZj5EOyVmM+QSO8z0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731055926; c=relaxed/simple; bh=RcuQuZgZt8m3bIkSzDHFRUXoABDd4tCxmGDliTqlQNc=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Fonc/VjUYiSLZmed1xDr+nJrYPKW8AtzJ29zPY8lyhB3y87vKBw9yZjVqey2unZapUA5JOIm3HwIDGnAnEp7J49SCf3kWT4IU5GpI/dHEUQgyP5wGAiFEiExXUoQmFLJH5Fm3gw9FiaNwVHxmc9McHOjQXrLgZwnSoALqX8SVQE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=microchip.com; spf=pass smtp.mailfrom=microchip.com; dkim=pass (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b=vV1G+6Ho; arc=none smtp.client-ip=68.232.154.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=microchip.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=microchip.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b="vV1G+6Ho" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1731055924; x=1762591924; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=RcuQuZgZt8m3bIkSzDHFRUXoABDd4tCxmGDliTqlQNc=; b=vV1G+6Ho796u1B6zXL/05iMhQkACH1cvk1ACND4lU4WbfQw1WI5AGP81 t0zpzhqdsLkVPP7pNUEbEr9WSZzhS68Dahgr6gt/N4WwxGWUZGGNDhZZF 9kd2xr4MR+LZ0pUg+G0PAvahpOPtdaWyyBGUzRKMV3tGuomJRHrSypVHo MveDbAYySauXEPKoA9AYYq9OMuSBCeF6HJrHmA7xEu5kjAo7VAVLErJED Ls4vSUOjRTixB8cBvn4IFbN0Xbs4QTX0TyMvqlwR5kKYC+Pm2JCWkmK6s plrHeCDUA+ECH0yoMoYsK30og91d0V5/4QoUMZYfGhAKNUfzISbH2xmqy w==; X-CSE-ConnectionGUID: zI5DMkGcRuGi35LBTBIEew== X-CSE-MsgGUID: SlkkJ54RTMK2kvi3oI6mXQ== X-IronPort-AV: E=Sophos;i="6.12,137,1728975600"; d="scan'208";a="33791006" X-Amp-Result: SKIPPED(no attachment in message) Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa4.microchip.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 08 Nov 2024 01:52:03 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.85.144) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Fri, 8 Nov 2024 01:51:49 -0700 Received: from vduicu-Virtual-Machine.mshome.net (10.10.85.11) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server id 15.1.2507.35 via Frontend Transport; Fri, 8 Nov 2024 01:51:47 -0700 From: To: , , , CC: , , , Subject: [PATCH v8] iio: adc: pac1921: Add ACPI support to Microchip pac1921 Date: Fri, 8 Nov 2024 10:50:12 +0200 Message-ID: <20241108085012.13147-1-victor.duicu@microchip.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Victor Duicu 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 --- The patch was tested on minnowboard and sama5. Differences related to previous versions: 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 | 98 +++++++++++++++++++++++++++++++++++---- 1 file changed, 89 insertions(+), 9 deletions(-) base-commit: 6415477ba63dea58b5cbf9ddcae75f18f33c71a4 diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index b0f6727cfe38..e24015390503 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -14,6 +14,7 @@ #include #include #include +#include /* pac1921 registers */ #define PAC1921_REG_GAIN_CFG 0x00 @@ -67,6 +68,12 @@ 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 (INT_MAX / MICRO) + /* * Pre-computed scale factors for BUS voltage * format: IIO_VAL_INT_PLUS_NANO @@ -204,6 +211,11 @@ struct pac1921_priv { } scan; }; +static inline bool pac1921_shunt_is_valid(u32 shunt_val) +{ + return shunt_val > 0 && shunt_val <= INT_MAX; +} + /* * Check if first integration after configuration update has completed. * @@ -782,7 +794,7 @@ 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; @@ -793,8 +805,13 @@ 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 > PAC1921_MAX_SHUNT_VALUE_OHMS) + return -EINVAL; + rshunt_uohm = val * MICRO + val_fract; - if (rshunt_uohm == 0 || rshunt_uohm > INT_MAX) + /* This check is to ensure rshunt_uohm is non-zero positive */ + if (!pac1921_shunt_is_valid(rshunt_uohm)) return -EINVAL; guard(mutex)(&priv->lock); @@ -1151,6 +1168,60 @@ 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; + 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); + + status = acpi_evaluate_dsm(handle, &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, &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 (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_valid(priv->rshunt_uohm)) + 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,