From patchwork Fri Oct 18 12:06:24 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: 13841690 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 94B646FC3; Fri, 18 Oct 2024 12:07:20 +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=1729253242; cv=none; b=JTYF2DDwOGU0Qfu7b6rbWf21EHKiNIn9PupG4f9grGtR0ng/ircYghtQUENYbAXz3BYkU8H6xT6BaCmxx3t3RnJXhdelvTI7fbcZKK2ZETwRT/5HOOYg8QzayXASZr92rK5fBv6PeBzAg2KNKGdNA/l2bAbzwBrK2PGmO5s0m9s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729253242; c=relaxed/simple; bh=URBOnJ/Ss5PaWSgCKIzSeXHcUY8k6lxtjhkvPrc0xhg=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=qVSlsoTcKY69YlrjRL4Vo1ajyWkonVCBHgwY8l5YixPxU6KtaZP49dw/VaKogpAZIjCvKSG4Gry/NR6miiXZ6Cm1EOUARlaDVKqGqs3Po/G+AmCBOVDBTkYfDFlVC2EV2NphBo8v4IRmdRChvgomiOKQ7UXotOxYZBvMPeTR+30= 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=JLAU8fU7; 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="JLAU8fU7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1729253240; x=1760789240; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=URBOnJ/Ss5PaWSgCKIzSeXHcUY8k6lxtjhkvPrc0xhg=; b=JLAU8fU75hGvk5c7edYg4XPv4MjvKJyZIgZfa4t8zVa6xIGUYXlKY73Z uLKS4aOOKJq/KPczXNKo+upOV6SyeY/G1nkfIOH3sFWlplwdzHBUI2vtY 8TpEinMnJ6ZDHx7EUDHPDzTz7NXronUAjqHtcVIPXTtF+NR01ND6/JiEj +cgGkhSEqTmfma7ZYwMKOLZZxx75GcwCL7zuhQ0bdc1l3jNFdMBFPyeCD nTWFgEvCS+Ulqz/Xamklk0W+cldy3EeC7GNWP0POgzgOhuJqgfF55GUa0 IrUbfOu1JFddNi0aTmHpNy0VKeboXzQuu+LMpN83OhcNcjlc3ovoMiKRi A==; X-CSE-ConnectionGUID: cunrz4YRRpeQeLPu+b1Gow== X-CSE-MsgGUID: k0qZE7O+S2uBKo6Hk5OdGw== X-IronPort-AV: E=Sophos;i="6.11,213,1725346800"; d="scan'208";a="32981640" 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; 18 Oct 2024 05:07:13 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Fri, 18 Oct 2024 05:06:48 -0700 Received: from vduicu-Virtual-Machine.mshome.net (10.10.85.11) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2507.35 via Frontend Transport; Fri, 18 Oct 2024 05:06:46 -0700 From: To: , , CC: , , , Subject: [PATCH v5] iio: adc: pac1921: Add ACPI support to Microchip pac1921 Date: Fri, 18 Oct 2024 15:06:24 +0300 Message-ID: <20241018120624.15409-1-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 cate: Fri, 18 Oct 2024 14:11:37 +0300 From: Victor Duicu This driver 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: 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 | 109 +++++++++++++++++++++++++++++++++----- 1 file changed, 96 insertions(+), 13 deletions(-) base-commit: 57573ace0c1b142433dfe3d63ebf375269c80fc1 diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index a96fae546bc1..9622b0da6196 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -67,6 +67,13 @@ 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 is 2Kohms */ +#define PAC1921_MAX_SHUNT_VALUE_OHMS 2000 +#define PAC1921_MAX_SHUNT_VALUE_UOHMS 2000000000 + /* * 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_invalid(u32 shunt_val) +{ + return (shunt_val == 0 || shunt_val > PAC1921_MAX_SHUNT_VALUE_UOHMS); +} + /* * Check if first integration after configuration update has completed. * @@ -781,7 +793,7 @@ 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; @@ -791,9 +803,13 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, ret = iio_str_to_fixpoint(buf, 100000, &val, &val_fract); 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); @@ -1150,6 +1166,71 @@ 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; + u32 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; @@ -1176,17 +1257,13 @@ 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)) @@ -1243,11 +1320,17 @@ 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,