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[23.128.96.18]) by mx.google.com with ESMTP id s15si5475412edj.165.2020.11.22.10.38.47; Sun, 22 Nov 2020 10:39:28 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=fail header.i=@roeck-us.net header.s=default header.b=mFrII85J; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728220AbgKVSdr (ORCPT + 99 others); Sun, 22 Nov 2020 13:33:47 -0500 Received: from gproxy5-pub.mail.unifiedlayer.com ([67.222.38.55]:52827 "EHLO gproxy5-pub.mail.unifiedlayer.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728062AbgKVSdr (ORCPT ); Sun, 22 Nov 2020 13:33:47 -0500 Received: from cmgw15.unifiedlayer.com (unknown [10.9.0.15]) by gproxy5.mail.unifiedlayer.com (Postfix) with ESMTP id 7E7FB140C73 for ; Sun, 22 Nov 2020 11:33:44 -0700 (MST) Received: from bh-25.webhostbox.net ([208.91.199.152]) by cmsmtp with ESMTP id guBDkGOZph41lguBEkKdvB; Sun, 22 Nov 2020 11:33:44 -0700 X-Authority-Reason: nr=8 X-Authority-Analysis: v=2.3 cv=FoUrAVjq c=1 sm=1 tr=0 a=QNED+QcLUkoL9qulTODnwA==:117 a=2cfIYNtKkjgZNaOwnGXpGw==:17 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=IkcTkHD0fZMA:10:nop_charset_1 a=nNwsprhYR40A:10:nop_rcvd_month_year a=evQFzbml-YQA:10:endurance_base64_authed_username_1 a=pGLkceISAAAA:8 a=FOH2dFAWAAAA:8 a=S0K3Dlqhgj2jpTZ7kyIA:9 a=7Zwj6sZBwVKJAoWSPKxL6X1jA+E=:19 a=QEXdDO2ut3YA:10:nop_charset_2 a=i3VuKzQdj-NEYjvDI-p3:22 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=roeck-us.net; s=default; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ogJoR4t2FLSCBCvF19QHUeRrfYPlQy7OvPK0KBHE4Ag=; b=mFrII85Jtz4l7NoBAx0REt5FtM nJh+lSVMDDAhKYXcmlKoPxkgecWbp8vYXWjbXUw2XJ1G43Up/sUvGiV005umu7J4Co+d18i/IhOmr ip3Nmws3PVw7rOeYw2QDfqpAMsT6BHeIkO6KHvri1lLkNtIkFgAklmdau+idNoKq/rq/nHLIHOKRW W18y8t0Z6zS+rH+IKcsUhdd+qNng1Js/7LPEACXy+Jsgv5bHBHvl2qDO3MZSGpKwd8vFPHrvAzc+a 0llgY8I1A10769BB5M5780T+VcyBFmVF2FGRjAC1GLrVBJYGdl2nmmnCVoZ69zP0teJsph1CO1xTS MsEL52eQ==; Received: from 108-223-40-66.lightspeed.sntcca.sbcglobal.net ([108.223.40.66]:45946 helo=localhost) by bh-25.webhostbox.net with esmtpa (Exim 4.93) (envelope-from ) id 1kguBD-000CT0-BK; Sun, 22 Nov 2020 18:33:43 +0000 Date: Sun, 22 Nov 2020 10:33:42 -0800 From: Guenter Roeck To: rentao.bupt@gmail.com Cc: Jean Delvare , Jonathan Corbet , linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org, taoren@fb.com, mikechoi@fb.com Subject: Re: [PATCH v3 1/2] hwmon: (max127) Add Maxim MAX127 hardware monitoring driver Message-ID: <20201122183342.GA69512@roeck-us.net> References: <20201119175324.22472-1-rentao.bupt@gmail.com> <20201119175324.22472-2-rentao.bupt@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201119175324.22472-2-rentao.bupt@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-BWhitelist: no X-Source-IP: 108.223.40.66 X-Source-L: No X-Exim-ID: 1kguBD-000CT0-BK X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 108-223-40-66.lightspeed.sntcca.sbcglobal.net (localhost) [108.223.40.66]:45946 X-Source-Auth: guenter@roeck-us.net X-Email-Count: 10 X-Source-Cap: cm9lY2s7YWN0aXZzdG07YmgtMjUud2ViaG9zdGJveC5uZXQ= X-Local-Domain: yes Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 19, 2020 at 09:53:23AM -0800, rentao.bupt@gmail.com wrote: > From: Tao Ren > > Add hardware monitoring driver for the Maxim MAX127 chip. > > MAX127 min/max range handling code is inspired by the max197 driver. > > Signed-off-by: Tao Ren Nice cleanup. Couple of minor comments. Thanks, Guenter > --- > Changes in v3: > - no code change. xdp maintainers were removed from to/cc list. > Changes in v2: > - replace devm_hwmon_device_register_with_groups() with > devm_hwmon_device_register_with_info() API. > - divide min/max read and write methods to separate functions. > - fix raw-to-vin conversion logic. > - refine ctrl_byte handling so mutex is not needed to protect the > byte. > - improve i2c_transfer() error handling. > - a few other improvements (comments, variable naming, and etc.). > > drivers/hwmon/Kconfig | 9 ++ > drivers/hwmon/Makefile | 1 + > drivers/hwmon/max127.c | 346 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 356 insertions(+) > create mode 100644 drivers/hwmon/max127.c > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 9d600e0c5584..716df51edc87 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -950,6 +950,15 @@ config SENSORS_MAX1111 > This driver can also be built as a module. If so, the module > will be called max1111. > > +config SENSORS_MAX127 > + tristate "Maxim MAX127 12-bit 8-channel Data Acquisition System" > + depends on I2C > + help > + Say y here to support Maxim's MAX127 DAS chips. > + > + This driver can also be built as a module. If so, the module > + will be called max127. > + > config SENSORS_MAX16065 > tristate "Maxim MAX16065 System Manager and compatibles" > depends on I2C > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > index 1083bbfac779..01ca5d3fbad4 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -127,6 +127,7 @@ obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o > obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o > obj-$(CONFIG_SENSORS_LTQ_CPUTEMP) += ltq-cputemp.o > obj-$(CONFIG_SENSORS_MAX1111) += max1111.o > +obj-$(CONFIG_SENSORS_MAX127) += max127.o > obj-$(CONFIG_SENSORS_MAX16065) += max16065.o > obj-$(CONFIG_SENSORS_MAX1619) += max1619.o > obj-$(CONFIG_SENSORS_MAX1668) += max1668.o > diff --git a/drivers/hwmon/max127.c b/drivers/hwmon/max127.c > new file mode 100644 > index 000000000000..3df4c225a6a2 > --- /dev/null > +++ b/drivers/hwmon/max127.c > @@ -0,0 +1,346 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Hardware monitoring driver for MAX127. > + * > + * Copyright (c) 2020 Facebook Inc. > + */ > + > +#include > +#include > +#include Not needed. > +#include > +#include > +#include > +#include Not needed. > + > +/* > + * MAX127 Control Byte. Refer to MAX127 datasheet, Table 1 "Control-Byte > + * Format" for details. > + */ > +#define MAX127_CTRL_START BIT(7) > +#define MAX127_CTRL_SEL_SHIFT 4 > +#define MAX127_CTRL_RNG BIT(3) > +#define MAX127_CTRL_BIP BIT(2) > +#define MAX127_CTRL_PD1 BIT(1) > +#define MAX127_CTRL_PD0 BIT(0) > + > +#define MAX127_NUM_CHANNELS 8 > +#define MAX127_SET_CHANNEL(ch) (((ch) & 7) << MAX127_CTRL_SEL_SHIFT) > + > +/* > + * MAX127 channel input ranges. Refer to MAX127 datasheet, Table 3 "Range > + * and Polarity Selection" for details. > + */ > +#define MAX127_FULL_RANGE 10000 /* 10V */ > +#define MAX127_HALF_RANGE 5000 /* 5V */ > + > +/* > + * MAX127 returns 2 bytes at read: > + * - the first byte contains data[11:4]. > + * - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB). > + * Refer to MAX127 datasheet, "Read a Conversion (Read Cycle)" section > + * for details. > + */ > +#define MAX127_DATA_LEN 2 > +#define MAX127_DATA_SHIFT 4 > + > +#define MAX127_SIGN_BIT BIT(11) > + > +struct max127_data { > + struct mutex lock; > + struct i2c_client *client; > + u8 ctrl_byte[MAX127_NUM_CHANNELS]; > +}; > + > +static int max127_select_channel(struct i2c_client *client, u8 ctrl_byte) > +{ > + int status; > + struct i2c_msg msg = { > + .addr = client->addr, > + .flags = 0, > + .len = sizeof(ctrl_byte), > + .buf = &ctrl_byte, > + }; > + > + status = i2c_transfer(client->adapter, &msg, 1); > + if (status < 0) > + return status; > + else if (status != 1) else after return is not needed. > + return -EIO; > + > + return 0; > +} > + > +static int max127_read_channel(struct i2c_client *client, long *val) > +{ > + int status; > + u8 i2c_data[MAX127_DATA_LEN]; > + struct i2c_msg msg = { > + .addr = client->addr, > + .flags = I2C_M_RD, > + .len = sizeof(i2c_data), > + .buf = i2c_data, > + }; > + > + status = i2c_transfer(client->adapter, &msg, 1); > + if (status < 0) > + return status; > + else if (status != 1) else after return is not needed. > + return -EIO; > + > + *val = (i2c_data[1] >> MAX127_DATA_SHIFT) | > + ((u16)i2c_data[0] << MAX127_DATA_SHIFT); > + return 0; > +} > + > +static long max127_process_raw(u8 ctrl_byte, long raw) > +{ > + long scale, weight; > + > + /* > + * MAX127's data coding is binary in unipolar mode with 1 LSB = > + * (Full-Scale/4096) and two’s complement binary in bipolar mode > + * with 1 LSB = [(2 x |FS|)/4096]. > + * Refer to MAX127 datasheet, "Transfer Function" section for > + * details. > + */ > + scale = (ctrl_byte & MAX127_CTRL_RNG) ? MAX127_FULL_RANGE : > + MAX127_HALF_RANGE; > + if (ctrl_byte & MAX127_CTRL_BIP) { > + weight = (raw & MAX127_SIGN_BIT); > + raw &= ~MAX127_SIGN_BIT; > + raw -= weight; > + raw *= 2; > + } > + > + return raw * scale / 4096; > +} > + > +static int max127_read_input(struct max127_data *data, int channel, long *val) > +{ > + long raw; > + int status; > + struct i2c_client *client = data->client; > + u8 ctrl_byte = data->ctrl_byte[channel]; > + > + mutex_lock(&data->lock); > + > + status = max127_select_channel(client, ctrl_byte); > + if (status) > + goto exit; > + > + status = max127_read_channel(client, &raw); > + if (status) > + goto exit; > + > + *val = max127_process_raw(ctrl_byte, raw); > + > +exit: > + mutex_unlock(&data->lock); > + return status; > +} > + > +static int max127_read_min(struct max127_data *data, int channel, long *val) > +{ > + u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3; > + static const int min_input_map[4] = { > + 0, /* RNG=0, BIP=0 */ > + -MAX127_HALF_RANGE, /* RNG=0, BIP=1 */ > + 0, /* RNG=1, BIP=0 */ > + -MAX127_FULL_RANGE, /* RNG=1, BIP=1 */ > + }; > + > + *val = min_input_map[rng_bip]; > + return 0; > +} > + > +static int max127_read_max(struct max127_data *data, int channel, long *val) > +{ > + u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3; > + static const int max_input_map[4] = { > + MAX127_HALF_RANGE, /* RNG=0, BIP=0 */ > + MAX127_HALF_RANGE, /* RNG=0, BIP=1 */ > + MAX127_FULL_RANGE, /* RNG=1, BIP=0 */ > + MAX127_FULL_RANGE, /* RNG=1, BIP=1 */ > + }; > + > + *val = max_input_map[rng_bip]; > + return 0; > +} > + > +static int max127_write_min(struct max127_data *data, int channel, long val) > +{ > + u8 ctrl; > + > + ctrl = data->ctrl_byte[channel]; > + if (val <= -MAX127_FULL_RANGE) { > + ctrl |= (MAX127_CTRL_RNG | MAX127_CTRL_BIP); > + } else if (val < 0) { > + ctrl |= MAX127_CTRL_BIP; > + ctrl &= ~MAX127_CTRL_RNG; > + } else { > + ctrl &= ~MAX127_CTRL_BIP; > + } > + data->ctrl_byte[channel] = ctrl; Needs mutex protection to avoid parallel writes (which might mess up ctrl_byte[channel]). > + > + return 0; > +} > + > +static int max127_write_max(struct max127_data *data, int channel, long val) > +{ > + if (val >= MAX127_FULL_RANGE) > + data->ctrl_byte[channel] |= MAX127_CTRL_RNG; > + else > + data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG; > + Same here, to avoid interaction with write_min (which might otherwise read ctrl and modify it at the same time as this function). > + return 0; > +} > + > +static umode_t max127_is_visible(const void *_data, > + enum hwmon_sensor_types type, > + u32 attr, int channel) > +{ > + if (type == hwmon_in) { > + switch (attr) { > + case hwmon_in_input: > + return 0444; > + > + case hwmon_in_min: > + case hwmon_in_max: > + return 0644; > + > + default: > + break; > + } > + } > + > + return 0; > +} > + > +static int max127_read(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, long *val) > +{ > + int status; > + struct max127_data *data = dev_get_drvdata(dev); > + > + if (type != hwmon_in) > + return -EOPNOTSUPP; > + > + switch (attr) { > + case hwmon_in_input: > + status = max127_read_input(data, channel, val); > + break; > + > + case hwmon_in_min: > + status = max127_read_min(data, channel, val); > + break; > + > + case hwmon_in_max: > + status = max127_read_max(data, channel, val); > + break; > + > + default: > + status = -EOPNOTSUPP; > + break; > + } > + > + return status; > +} > + > +static int max127_write(struct device *dev, enum hwmon_sensor_types type, > + u32 attr, int channel, long val) > +{ > + int status; > + struct max127_data *data = dev_get_drvdata(dev); > + > + if (type != hwmon_in) > + return -EOPNOTSUPP; > + > + switch (attr) { > + case hwmon_in_min: > + status = max127_write_min(data, channel, val); > + break; > + > + case hwmon_in_max: > + status = max127_write_max(data, channel, val); > + break; > + > + default: > + status = -EOPNOTSUPP; > + break; > + } > + > + return status; > +} > + > +static const struct hwmon_ops max127_hwmon_ops = { > + .is_visible = max127_is_visible, > + .read = max127_read, > + .write = max127_write, > +}; > + > +static const struct hwmon_channel_info *max127_info[] = { > + HWMON_CHANNEL_INFO(in, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, > + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX), > + NULL, > +}; > + > +static const struct hwmon_chip_info max127_chip_info = { > + .ops = &max127_hwmon_ops, > + .info = max127_info, > +}; > + > +static int max127_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + int i; > + struct device *hwmon_dev; > + struct max127_data *data; > + struct device *dev = &client->dev; > + > + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + data->client = client; > + mutex_init(&data->lock); > + for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++) > + data->ctrl_byte[i] = (MAX127_CTRL_START | > + MAX127_SET_CHANNEL(i)); > + > + hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, > + data, > + &max127_chip_info, > + NULL); > + > + return PTR_ERR_OR_ZERO(hwmon_dev); > +} > + > +static const struct i2c_device_id max127_id[] = { > + { "max127", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(i2c, max127_id); > + > +static struct i2c_driver max127_driver = { > + .class = I2C_CLASS_HWMON, > + .driver = { > + .name = "max127", > + }, > + .probe = max127_probe, > + .id_table = max127_id, > +}; > + > +module_i2c_driver(max127_driver); > + > +MODULE_LICENSE("GPL"); > +MODULE_AUTHOR("Mike Choi "); > +MODULE_AUTHOR("Tao Ren "); > +MODULE_DESCRIPTION("MAX127 Hardware Monitoring driver");