From patchwork Thu Mar 14 18:38:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Guenter Roeck X-Patchwork-Id: 10853387 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2D5EC6C2 for ; Thu, 14 Mar 2019 18:38:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 173582A393 for ; Thu, 14 Mar 2019 18:38:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 07F0D2A6BB; Thu, 14 Mar 2019 18:38:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 25E432A393 for ; Thu, 14 Mar 2019 18:38:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726952AbfCNSiX (ORCPT ); Thu, 14 Mar 2019 14:38:23 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:36325 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726936AbfCNSiX (ORCPT ); Thu, 14 Mar 2019 14:38:23 -0400 Received: by mail-pg1-f196.google.com with SMTP id r124so4587919pgr.3 for ; Thu, 14 Mar 2019 11:38:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=TbEWpo/3ryxSxkaqX8Sw49oVqpkjsBlO/9ID/CljCNU=; b=WXnYMwM2Sqo4FDLOcQl6FZrIkB0lCKN4woxrEze9DMlhJNVnto2+teQC8WjZ4wRvsH XEdpdaq3YlZUxnOBZ8lb7x/d9f/gLu1Gmi5kT0//vIQJCd0r38Wbf6nE4/9kV4klmJHI I21thWHqLNWGmQZJVER//Ncl7ZUCzdhQ9ou7eJHQ/gaHJ1U5juiyQpguYUvggY+BmH51 2EGhexXFJdjj+yWF+ITbwmRjLk/nvYfFMY+zENZgbAuK8Chy9wvGW3lal4L6hZW20mLS GKLlF8xQWARyUct3TljCtqIDzfMZtyJ0oBe+Objd5n7cpU129J+8C905jnw0Sjqud5Vz VCIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=TbEWpo/3ryxSxkaqX8Sw49oVqpkjsBlO/9ID/CljCNU=; b=e5+lSXqd44x825JM5zn20Ab/lIfSILmYc7jn7VCVMOT4Zw8GLb7+gKVDxhlqf9SMEO f1U8FEThypyNjFBBX37ZuoI6PUg3BqlcGQmWS6SLumFH69kqE2tpm1bsU89oA548GziS PKhCe7gkfBGBW4pMmZqDUqVvxg8LtFVYRRMvrr5Hj60owrAjvwxHkTl4PUIcIMZ81Dj8 DkXRp9ez2MXkt5bB4YftSKcF4nPUpXTfOJVY4trv09y7STrAxjQS96v/HVW2/Q7X9eUf sbb7WrSEYcPK08jJHfpqPLI6/DFDPUNiMB1nzJY7VsNKWhea48ICcJbRRLeocvx/LWOj /zUQ== X-Gm-Message-State: APjAAAV1KYrldextnBfOIhlt5kUk+6xeCnr7Luxj/I9qUBOG6MUAGOfQ WWm4khs4ncAJwXaxygi07E+RG/4k X-Google-Smtp-Source: APXvYqxDzX7/Z2EFe4Fzv8bI0hYyqyRSqbI2a8ahonHr5a4U0LWKOFEpFbLAwh/4RBBMs1zmiG7wFA== X-Received: by 2002:a62:7993:: with SMTP id u141mr4429633pfc.252.1552588701769; Thu, 14 Mar 2019 11:38:21 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id e131sm34168300pfc.62.2019.03.14.11.38.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Mar 2019 11:38:20 -0700 (PDT) From: Guenter Roeck To: Hardware Monitoring Cc: Jean Delvare , Guenter Roeck , =?utf-8?q?Christian_Gr=C3=B6nke?= Subject: [PATCH] hwmon: (pmbus) Add IEEE 754 half precision support to PMBus core Date: Thu, 14 Mar 2019 11:38:19 -0700 Message-Id: <1552588699-1199-1-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP PMBus v1.3.1 adds IEEE 754 half precision as additional data format. Add support for it. Cc: Christian Grönke Signed-off-by: Guenter Roeck --- drivers/hwmon/pmbus/pmbus.h | 2 +- drivers/hwmon/pmbus/pmbus_core.c | 142 +++++++++++++++++++++++++++++++++++++-- 2 files changed, 139 insertions(+), 5 deletions(-) diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h index 1d24397d36ec..6477eb433790 100644 --- a/drivers/hwmon/pmbus/pmbus.h +++ b/drivers/hwmon/pmbus/pmbus.h @@ -374,7 +374,7 @@ enum pmbus_sensor_classes { #define PMBUS_PAGE_VIRTUAL BIT(31) -enum pmbus_data_format { linear = 0, direct, vid }; +enum pmbus_data_format { linear = 0, ieee754, direct, vid }; enum vrm_version { vr11 = 0, vr12, vr13 }; struct pmbus_driver_info { diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index 2e2b5851139c..e1be5ebed57f 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -619,6 +619,66 @@ static struct pmbus_data *pmbus_update_device(struct device *dev) } /* + * Convert ieee754 sensor values to milli- or micro-units + * depending on sensor type. + * + * ieee754 data format: + * bit 15: sign + * bit 10..14: exponent + * bit 0..9: mantissa + * exponent=0: + * v=(−1)^signbit * 2^(−14) * 0.significantbits + * exponent=1..30: + * v=(−1)^signbit * 2^(exponent - 15) * 1.significantbits + * exponent=31: + * v=NaN + * + * Add the number mantissa bits into the calculations for simplicity. + * To do that, add '10' to the exponent. By doing that, we can just add + * 0x400 to normal values and get the expected result. + */ +static long pmbus_reg2data_ieee754(struct pmbus_data *data, + struct pmbus_sensor *sensor) +{ + int exponent; + bool sign; + long val; + + /* only support half precision for now */ + sign = sensor->data & 0x8000; + exponent = (sensor->data >> 10) & 0x1f; + val = sensor->data & 0x3ff; + + if (exponent == 0) { /* subnormal */ + exponent = -(14 + 10); + } else if (exponent == 0x1f) { /* NaN, convert to min/max */ + exponent = 0; + val = 65504; + } else { + exponent -= (15 + 10); /* normal */ + val |= 0x400; + } + + /* scale result to milli-units for all sensors except fans */ + if (sensor->class != PSC_FAN) + val = val * 1000L; + + /* scale result to micro-units for power sensors */ + if (sensor->class == PSC_POWER) + val = val * 1000L; + + if (exponent >= 0) + val <<= exponent; + else + val >>= -exponent; + + if (sign) + val = -val; + + return val; +} + +/* * Convert linear sensor values to milli- or micro-units * depending on sensor type. */ @@ -740,6 +800,9 @@ static long pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor) case vid: val = pmbus_reg2data_vid(data, sensor); break; + case ieee754: + val = pmbus_reg2data_ieee754(data, sensor); + break; case linear: default: val = pmbus_reg2data_linear(data, sensor); @@ -748,8 +811,72 @@ static long pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor) return val; } -#define MAX_MANTISSA (1023 * 1000) -#define MIN_MANTISSA (511 * 1000) +#define MAX_IEEE_MANTISSA (0x7ff * 1000) +#define MIN_IEEE_MANTISSA (0x400 * 1000) + +static u16 pmbus_data2reg_ieee754(struct pmbus_data *data, + struct pmbus_sensor *sensor, long val) +{ + u16 exponent = (15 + 10); + long mantissa; + u16 sign = 0; + + /* simple case */ + if (val == 0) + return 0; + + if (val < 0) { + sign = 0x8000; + val = -val; + } + + /* Power is in uW. Convert to mW before converting. */ + if (sensor->class == PSC_POWER) + val = DIV_ROUND_CLOSEST(val, 1000L); + + /* + * For simplicity, convert fan data to milli-units + * before calculating the exponent. + */ + if (sensor->class == PSC_FAN) + val = val * 1000; + + /* Reduce large mantissa until it fits into 10 bit */ + while (val > MAX_IEEE_MANTISSA && exponent < 30) { + exponent++; + val >>= 1; + } + /* + * Increase small mantissa to generate valid 'normal' + * number + */ + while (val < MIN_IEEE_MANTISSA && exponent > 1) { + exponent--; + val <<= 1; + } + + /* Convert mantissa from milli-units to units */ + mantissa = DIV_ROUND_CLOSEST(val, 1000); + + /* + * Ensure that the resulting number is within range. + * Valid range is 0x400..0x7ff, where bit 10 reflects + * the implied high bit in normalized ieee754 numbers. + * Set the range to 0x400..0x7ff to reflect this. + * The upper bit is then removed by the mask against + * 0x3ff in the final assignment. + */ + if (mantissa > 0x7ff) + mantissa = 0x7ff; + else if (mantissa < 0x400) + mantissa = 0x400; + + /* Convert to sign, 5 bit exponent, 10 bit mantissa */ + return sign | (mantissa & 0x3ff) | ((exponent << 10) & 0x7c00); +} + +#define MAX_LIN_MANTISSA (1023 * 1000) +#define MIN_LIN_MANTISSA (511 * 1000) static u16 pmbus_data2reg_linear(struct pmbus_data *data, struct pmbus_sensor *sensor, long val) @@ -795,12 +922,12 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, val = val * 1000; /* Reduce large mantissa until it fits into 10 bit */ - while (val >= MAX_MANTISSA && exponent < 15) { + while (val >= MAX_LIN_MANTISSA && exponent < 15) { exponent++; val >>= 1; } /* Increase small mantissa to improve precision */ - while (val < MIN_MANTISSA && exponent > -15) { + while (val < MIN_LIN_MANTISSA && exponent > -15) { exponent--; val <<= 1; } @@ -878,6 +1005,9 @@ static u16 pmbus_data2reg(struct pmbus_data *data, case vid: regval = pmbus_data2reg_vid(data, sensor, val); break; + case ieee754: + regval = pmbus_data2reg_ieee754(data, sensor, val); + break; case linear: default: regval = pmbus_data2reg_linear(data, sensor, val); @@ -1967,6 +2097,10 @@ static int pmbus_identify_common(struct i2c_client *client, if (data->info->format[PSC_VOLTAGE_OUT] != direct) return -ENODEV; break; + case 3: /* ieee 754 half precision */ + if (data->info->format[PSC_VOLTAGE_OUT] != ieee754) + return -ENODEV; + break; default: return -ENODEV; }