From nobody Mon Nov 25 20:51:06 2024 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 8D4DF14F11E; Thu, 24 Oct 2024 10:02:03 +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=1729764126; cv=none; b=DGlV59BvATyHgYL/1eZ6g+wQBefLzV3UcXF3l23O+v7blraIBM7tLPBU08RyCdNdfpHpQIIL7aBQ+DBjvsiAx8gySeOOJBZOaWhC8ASSDLf/MPUvPcGaAsI+nA+Opg87IFDlJRf+D8fpZX1Gq8YOsmcWlWmVXlJH80IpNT0sChY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729764126; c=relaxed/simple; bh=L4OBI9kmzhb8Y5Z7ccxqHqPubs7j/bYb/whltKZ13n8=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Iv2PLGr9AIPE+lG31M/Dui+xGrZNnmt3pyKz0Y2hwFemS/zkRzBFvTU2RF+QEAjMV2sPcMyCBihnLdyqU22De3XqJkq02af179PpeUvKJisAe7dBFRhmLgG4LEPxIOMLq4TPEMUGIkrvp5g4htGERXCGg71f+Dhf99SjuvMGli8= 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=x9wy6+L7; 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="x9wy6+L7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1729764123; x=1761300123; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=L4OBI9kmzhb8Y5Z7ccxqHqPubs7j/bYb/whltKZ13n8=; b=x9wy6+L7+A4z6HGFs/7RedsuyfTXri6r2lVLdDYH015ziiHy0xYStmpT UKPeL9tLRqD1GHph6X2ZBc1IJgOYjvhD5YoRhrSBydj4wG8tsdp/W5A8T 0enFSNCIMOnra9UtbWFGp8dolB978qmJZQF/6zqZl0J0YkocrJOUOG/ro 8dj0u3m2wZYaXV94MV2JhL4f1j9gYFAReG982kezB2nDAUpq+HhXInFGj PRHLxl8FKMF3Pw7u+XDdUUq8l3VyfP+2itnHa6qNTvxUzSAhRN+jKJD9F dWpPS5JemxMnBTyGK59nzfPMdzyB7x+fh6Q4alAxGJAAutR4gG80u+mqg w==; X-CSE-ConnectionGUID: SzYnXIcCSW+5oX6M0jz6iw== X-CSE-MsgGUID: hd12t9s6RUK6zhh9WJd9mA== X-IronPort-AV: E=Sophos;i="6.11,228,1725346800"; d="scan'208";a="200854445" X-Amp-Result: SKIPPED(no attachment in message) Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 24 Oct 2024 03:02:02 -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; Thu, 24 Oct 2024 03:01:41 -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; Thu, 24 Oct 2024 03:01:40 -0700 From: To: , , CC: , , , Subject: [PATCH v6] iio: adc: pac1921: Add ACPI support to Microchip pac1921 Date: Thu, 24 Oct 2024 13:00:50 +0300 Message-ID: <20241024100050.4727-1-victor.duicu@microchip.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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: 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 u= 64. - 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 | 106 +++++++++++++++++++++++++++++++++----- 1 file changed, 93 insertions(+), 13 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index a96fae546bc1..cbbb3c1525c1 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -67,6 +67,12 @@ 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) = */ =20 +#define PAC1921_ACPI_GET_UOHMS_VALS 0 +#define PAC1921_ACPI_GET_LABEL 1 +#define PAC1921_DSM_UUID "f7bb9932-86ee-4516-a236-7= a7a742e55cb" +/* The maximum accepted value of shunt_resistor in UOHMS <=3D INT_MAX */ +#define PAC1921_MAX_SHUNT_VALUE_OHMS 2147 + /* * Pre-computed scale factors for BUS voltage * format: IIO_VAL_INT_PLUS_NANO @@ -204,6 +210,11 @@ struct pac1921_priv { } scan; }; =20 +static inline bool pac1921_shunt_is_invalid(u32 shunt_val) +{ + return (shunt_val =3D=3D 0 || shunt_val > INT_MAX); +} + /* * Check if first integration after configuration update has completed. * @@ -781,7 +792,7 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_= dev *indio_dev, const char *buf, size_t len) { struct pac1921_priv *priv =3D iio_priv(indio_dev); - u64 rshunt_uohm; + u32 rshunt_uohm; int val, val_fract; int ret; =20 @@ -792,8 +803,12 @@ static ssize_t pac1921_write_shunt_resistor(struct iio= _dev *indio_dev, if (ret) return ret; =20 + /* This check is to ensure val * MICRO won't overflow */ + if (val < 0 || val > PAC1921_MAX_SHUNT_VALUE_OHMS) + return -EINVAL; + rshunt_uohm =3D val * MICRO + val_fract; - if (rshunt_uohm =3D=3D 0 || rshunt_uohm > INT_MAX) + if (pac1921_shunt_is_invalid(rshunt_uohm)) return -EINVAL; =20 guard(mutex)(&priv->lock); @@ -1150,6 +1165,69 @@ static void pac1921_regulator_disable(void *data) regulator_disable(regulator); } =20 +/* + * documentation related to the ACPI device definition + * https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/Applicat= ionNotes/ApplicationNotes/PAC193X-Integration-Notes-for-Microsoft-Windows-1= 0-and-Windows-11-Driver-Support-DS00002534.pdf + */ +static int pac1921_match_acpi_device(struct i2c_client *client, struct pac= 1921_priv *priv, + struct iio_dev *indio_dev) +{ + acpi_handle handle; + union acpi_object *rez; + guid_t guid; + char *label; + + guid_parse(PAC1921_DSM_UUID, &guid); + handle =3D ACPI_HANDLE(&client->dev); + + rez =3D 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"); + + priv->rshunt_uohm =3D rez->package.elements[0].integer.value; + ACPI_FREE(rez); + + if (pac1921_shunt_is_invalid(priv->rshunt_uohm)) + return dev_err_probe(&client->dev, -EINVAL, "Invalid shunt resistor\n"); + + pac1921_calc_current_scales(priv); + + rez =3D 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 =3D devm_kmemdup(&client->dev, rez->package.elements->string.pointe= r, + (size_t)rez->package.elements->string.length + 1, + GFP_KERNEL); + label[rez->package.elements->string.length] =3D '\0'; + indio_dev->label =3D label; + ACPI_FREE(rez); + + return 0; +} + +static int pac1921_parse_of_fw(struct i2c_client *client, struct pac1921_p= riv *priv) +{ + int ret; + struct device *dev =3D &client->dev; + + ret =3D 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 =3D &client->dev; @@ -1176,17 +1254,13 @@ static int pac1921_probe(struct i2c_client *client) priv->di_gain =3D PAC1921_DEFAULT_DI_GAIN; priv->n_samples =3D PAC1921_DEFAULT_NUM_SAMPLES; =20 - ret =3D 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 =3D=3D 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 =3D pac1921_match_acpi_device(client, priv, indio_dev); + else + ret =3D pac1921_parse_of_fw(client, priv); + if (ret < 0) + return dev_err_probe(&client->dev, ret, + "parameter parsing error\n"); =20 priv->vdd =3D devm_regulator_get(dev, "vdd"); if (IS_ERR(priv->vdd)) @@ -1243,11 +1317,17 @@ static const struct of_device_id pac1921_of_match[]= =3D { }; MODULE_DEVICE_TABLE(of, pac1921_of_match); =20 +static const struct acpi_device_id pac1921_acpi_match[] =3D { + { "MCHP1921" }, + { } +}; +MODULE_DEVICE_TABLE(acpi, pac1921_acpi_match); static struct i2c_driver pac1921_driver =3D { .driver =3D { .name =3D "pac1921", .pm =3D pm_sleep_ptr(&pac1921_pm_ops), .of_match_table =3D pac1921_of_match, + .acpi_match_table =3D pac1921_acpi_match }, .probe =3D pac1921_probe, .id_table =3D pac1921_id, base-commit: 185a947e0ef928226f99c05fc973cde872806aa1 --=20 2.43.0