From nobody Mon Nov 25 00:31:35 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 9D1C013B7B3; Thu, 31 Oct 2024 06:52:58 +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=1730357581; cv=none; b=DP4j1TnFtWPtasZZg7aVRJQdSixiHTmWZWreaiteAJzFTJvcvaUkfDhTflz/8SRiUpnJ/lz4prZXDK7l7ORr7Dqfr1MigxCTVzkCl68XvzRfcbu0cT/1waJKzPph2t1mYmzlFQtHLe5tk+8m5SXg/LL8CE+24ZAWm8387N/d9kg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730357581; c=relaxed/simple; bh=qeer1kcG6Rrt9N7t9xff6/AxPGGMumIvHuxnkuoA0o0=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=hdrueE39GvCaDSBFwpN3359stlO55eNGUwpTfa6dYyPjpTUG1DoILu8SkSksd+d7/FmrIp+MYpIuU3dA+77O8HdCbEXhQkjAKc2y+aiHmC0HmOb466ELoz1Y1kb6Yj28/iWPFdDMQAsWLbQbp1d9Ocfwh93WAv1P4Ze+zXp3Llw= 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=VUPyZkrN; 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="VUPyZkrN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1730357578; x=1761893578; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=qeer1kcG6Rrt9N7t9xff6/AxPGGMumIvHuxnkuoA0o0=; b=VUPyZkrNhscmhydev7kCTwL2zrSannw6kv4CiIL0ymGSGXlMxUgzORYn Kixu+58P0Mt4rbJwLx2DX+3sAVE8Brzrfp8wP66W/Blltlm8lO6RPqFHU enzUeOPJ0SrvZtWUb6JTosHsp5aaHb2TELjX99VV96NbJ2nhWhP1hEFKs kXqt0cKlr9y0p8LPny000ddIC95l9BzKUuxQ9Ab35Iq0Ul4McWw1gNAK7 vwF40sAkfvUQ1AgP2PIuRgKk1GlJoLP2GCdtErz5Omf4Df7js6/ABEH7Y qC7dHzENlRteUqb53etOq5oZuVGL2oEsXXBxjBdhLJp1/8eAKSjs4uPVD Q==; X-CSE-ConnectionGUID: 8YQN047qTAmKFCMPLpdrLg== X-CSE-MsgGUID: 50sPAILrQkaR/pGgxJQQmQ== X-IronPort-AV: E=Sophos;i="6.11,247,1725346800"; d="scan'208";a="201134074" 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; 30 Oct 2024 23:52:51 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Wed, 30 Oct 2024 23:52:22 -0700 Received: from vduicu-Virtual-Machine.mshome.net (10.10.85.11) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2507.35 via Frontend Transport; Wed, 30 Oct 2024 23:52:21 -0700 From: To: , , CC: , , , Subject: [PATCH v7] iio: adc: pac1921: Add ACPI support to Microchip pac1921 Date: Thu, 31 Oct 2024 08:52:05 +0200 Message-ID: <20241031065205.50154-1-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: 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 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 | 95 +++++++++++++++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 9 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index a96fae546bc1..c6c8d85e3092 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 +1165,60 @@ 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 iio_dev *indio_dev) +{ + acpi_handle handle; + union acpi_object *rez; + guid_t guid; + char *label; + struct pac1921_priv *priv =3D iio_priv(indio_dev); + struct device *dev =3D &priv->client->dev; + + guid_parse(PAC1921_DSM_UUID, &guid); + handle =3D ACPI_HANDLE(dev); + + rez =3D 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 =3D rez->package.elements[0].integer.value; + ACPI_FREE(rez); + + rez =3D 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 =3D devm_kstrdup(dev, rez->package.elements->string.pointer, GFP_KE= RNEL); + if (!label) + return dev_err_probe(dev, -EINVAL, "Label is NULL\n"); + + indio_dev->label =3D label; + ACPI_FREE(rez); + + return 0; +} + +static int pac1921_parse_of_fw(struct iio_dev *indio_dev) +{ + int ret; + struct pac1921_priv *priv =3D iio_priv(indio_dev); + struct device *dev =3D &priv->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"); + + return 0; +} + static int pac1921_probe(struct i2c_client *client) { struct device *dev =3D &client->dev; @@ -1176,14 +1245,16 @@ 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) + if (ACPI_HANDLE(dev)) + ret =3D pac1921_match_acpi_device(indio_dev); + else + ret =3D 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 =3D=3D 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); =20 pac1921_calc_current_scales(priv); @@ -1243,11 +1314,17 @@ 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: e2687d0723257db5025a4cf8cefbd80bed1e2681 --=20 2.43.0