From patchwork Thu Feb 6 01:43:27 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Courtney Cavin X-Patchwork-Id: 3592621 X-Patchwork-Delegate: eduardo.valentin@ti.com Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 273B19F392 for ; Thu, 6 Feb 2014 01:42:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 171572016C for ; Thu, 6 Feb 2014 01:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B749020108 for ; Thu, 6 Feb 2014 01:42:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753183AbaBFBmE (ORCPT ); Wed, 5 Feb 2014 20:42:04 -0500 Received: from seldrel01.sonyericsson.com ([212.209.106.2]:13239 "EHLO seldrel01.sonyericsson.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751769AbaBFBmD (ORCPT ); Wed, 5 Feb 2014 20:42:03 -0500 From: Courtney Cavin To: , CC: , , , , , , , , , , Subject: [PATCH] thermal: add generic IIO channel thermal sensor driver Date: Wed, 5 Feb 2014 17:43:27 -0800 Message-ID: <1391651007-29813-1-git-send-email-courtney.cavin@sonymobile.com> X-Mailer: git-send-email 1.8.1.5 MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This driver is a generic method for using IIO ADC channels as thermal sensors. Signed-off-by: Courtney Cavin --- .../devicetree/bindings/thermal/iio-thermal.txt | 46 +++++ drivers/thermal/Kconfig | 13 ++ drivers/thermal/Makefile | 1 + drivers/thermal/iio_thermal.c | 207 +++++++++++++++++++++ 4 files changed, 267 insertions(+) create mode 100644 Documentation/devicetree/bindings/thermal/iio-thermal.txt create mode 100644 drivers/thermal/iio_thermal.c diff --git a/Documentation/devicetree/bindings/thermal/iio-thermal.txt b/Documentation/devicetree/bindings/thermal/iio-thermal.txt new file mode 100644 index 0000000..3be11b6 --- /dev/null +++ b/Documentation/devicetree/bindings/thermal/iio-thermal.txt @@ -0,0 +1,46 @@ +Generic IIO channel thermal sensor bindings + +compatible: + Usage: required + Type: string + Desc: compatible string, must be "iio-thermal" + +conversion-method: + Usage: required + Type: string + Desc: How to convert IIO voltage values to temperature, one of: + "interpolation" - interpolate between values in lookup table + "scalar" - use values as multiplier and divisor + +conversion-values: + Usage: required + Type: u32 array, 2-tuples + Desc: lookup table for conversion, for conversion-method: + "interpolation" - 2-tuples of < uV mK >; micro-volts to + milli-kelvin; table must ascend + "scalar" - single scalar 2-tuple as < M D >; where: + mK = uV * M / D + +io-channels: + Usage: required + Type: prop-encoded-array + Desc: See bindings/iio/iio-bindings.txt; must be a voltage channel + +Example: + +vadc: some_vadc { + compatible = "..."; + #io-channel-cells = <1>; +}; + +iio-thermal { + compatible = "iio-thermal"; + io-channels = <&vadc 0>; + conversion-method = "interpolation"; + conversion-values = < + 30000 398200 + 385000 318200 + 1738000 233200 + >; +}; + diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 35c0664..f83a8e8 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -114,6 +114,19 @@ config THERMAL_EMULATION because userland can easily disable the thermal policy by simply flooding this sysfs node with low temperature values. +config IIO_THERMAL + tristate "Temperature sensor driver for generic IIO channels" + depends on IIO + depends on THERMAL_OF + help + Support for generic IIO channels, such as ADCs. This driver allows + you to expose an IIO voltage channel as a thermal sensor. This is + implemented as a thermal sensor, not a thermal zone, and thus + requires DT defined thermal infrastructure in order to be useful. + + If you aren't sure that you need this support, or haven't configured + a thermal infrastructure in device tree, you should say 'N' here. + config IMX_THERMAL tristate "Temperature sensor driver for Freescale i.MX SoCs" depends on CPU_THERMAL diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index 54e4ec9..0ee2c92 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -25,6 +25,7 @@ obj-y += samsung/ obj-$(CONFIG_DOVE_THERMAL) += dove_thermal.o obj-$(CONFIG_DB8500_THERMAL) += db8500_thermal.o obj-$(CONFIG_ARMADA_THERMAL) += armada_thermal.o +obj-$(CONFIG_IIO_THERMAL) += iio_thermal.o obj-$(CONFIG_IMX_THERMAL) += imx_thermal.o obj-$(CONFIG_DB8500_CPUFREQ_COOLING) += db8500_cpufreq_cooling.o obj-$(CONFIG_INTEL_POWERCLAMP) += intel_powerclamp.o diff --git a/drivers/thermal/iio_thermal.c b/drivers/thermal/iio_thermal.c new file mode 100644 index 0000000..df21dbc --- /dev/null +++ b/drivers/thermal/iio_thermal.c @@ -0,0 +1,207 @@ +/* + * An IIO channel based thermal sensor driver + * + * Copyright (C) 2014 Sony Mobile Communications, AB + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define MILLIKELVIN_0C 273150 + +struct iio_thermal_conv { + s32 *values; + int ntuple; + long (*convert)(const struct iio_thermal_conv *, int val); +}; + +struct iio_thermal { + struct thermal_zone_device *tz; + struct iio_channel *chan; + struct iio_thermal_conv conv; +}; + +static int iio_bsearch(const struct iio_thermal_conv *conv, s32 input) +{ + int h = conv->ntuple - 1; + int l = 0; + + while (h - 1 > l) { + int m = (l + h) & ~1; + s32 v = conv->values[m]; + if (v < input) + l = m >> 1; + else + h = m >> 1; + } + + return h; +} + +static long iio_thermal_interpolate(const struct iio_thermal_conv *conv, int v) +{ + int n; + + n = iio_bsearch(conv, v); + if (n == 0 || n == conv->ntuple) { + BUG(); + } else { + s32 *pts = &conv->values[(n-1)*2]; + s32 sx = pts[3] - pts[1]; + s32 sy = pts[2] - pts[0]; + return sx * (v - pts[0]) / sy + pts[1]; + } +} + +static long iio_thermal_scale(const struct iio_thermal_conv *conv, int v) +{ + return div_s64((s64)v * conv->values[0], conv->values[1]); +} + +static int iio_thermal_get_temp(void *pdata, long *value) +{ + struct iio_thermal *iio = pdata; + long temp; + int val; + int rc; + + rc = iio_read_channel_processed(iio->chan, &val); + if (rc) + return rc; + + temp = iio->conv.convert(&iio->conv, val); + + /* thermal core wants milli-celsius; we deal in milli-kelvin */ + temp = temp - MILLIKELVIN_0C; + + /* + * Although it would appear that the temperature value here is a + * signed value for sensors, the underlying thermal zone core + * doesn't deal with negative temperature. Cut this value off at 0C. + */ + *value = (temp < 0) ? 0 : temp; + + return 0; +} + +static int iio_thermal_probe(struct platform_device *pdev) +{ + struct iio_thermal *iio; + const void *values; + const char *type; + int rc; + + dev_info(&pdev->dev, "registering IIO thermal device\n"); + iio = devm_kzalloc(&pdev->dev, sizeof(*iio), GFP_KERNEL); + if (!iio) + return -ENOMEM; + + values = of_get_property(pdev->dev.of_node, + "conversion-values", &iio->conv.ntuple); + if (values == NULL || (iio->conv.ntuple % (sizeof(u32) * 2)) != 0) { + dev_err(&pdev->dev, "invalid/missing conversion values\n"); + return -EINVAL; + } + iio->conv.ntuple /= sizeof(u32) * 2; + iio->conv.values = devm_kzalloc(&pdev->dev, + sizeof(u32) * 2 * iio->conv.ntuple, GFP_KERNEL); + if (!iio->conv.values) + return -ENOMEM; + + rc = of_property_read_u32_array(pdev->dev.of_node, + "conversion-values", (u32 *)iio->conv.values, + iio->conv.ntuple * 2); + if (rc) { + dev_err(&pdev->dev, "invalid/missing conversion values\n"); + return -EINVAL; + } + + rc = of_property_read_string(pdev->dev.of_node, + "conversion-method", &type); + if (rc) { + dev_err(&pdev->dev, "invalid/missing conversion method\n"); + return rc; + } + if (!strcmp(type, "interpolation") && iio->conv.ntuple > 1) { + if (iio->conv.values[0] > iio->conv.values[2]) { + dev_err(&pdev->dev, + "conversion values should ascend\n"); + return rc; + } + iio->conv.convert = iio_thermal_interpolate; + } else if (!strcmp(type, "scalar") && iio->conv.ntuple == 1) { + iio->conv.convert = iio_thermal_scale; + } else { + dev_err(&pdev->dev, "invalid conversion method for values\n"); + return rc; + } + + iio->chan = iio_channel_get(&pdev->dev, NULL); + if (IS_ERR(iio->chan)) { + dev_err(&pdev->dev, "invalid/missing iio channel\n"); + return PTR_ERR(iio->chan); + } + if (iio->chan->channel->type != IIO_VOLTAGE) { + dev_err(&pdev->dev, "specified iio channel is not voltage\n"); + iio_channel_release(iio->chan); + return -EINVAL; + } + platform_set_drvdata(pdev, iio); + + iio->tz = thermal_zone_of_sensor_register(&pdev->dev, 0, iio, + iio_thermal_get_temp, NULL); + if (IS_ERR(iio->tz)) { + dev_err(&pdev->dev, "failed to register thermal sensor\n"); + iio_channel_release(iio->chan); + return PTR_ERR(iio->tz); + } + dev_info(&pdev->dev, "successfully registered IIO thermal sensor\n"); + + return 0; +} + +static int iio_thermal_remove(struct platform_device *pdev) +{ + struct iio_thermal *iio; + + iio = platform_get_drvdata(pdev); + + thermal_zone_of_sensor_unregister(&pdev->dev, iio->tz); + iio_channel_release(iio->chan); + + return 0; +} + +static const struct of_device_id iio_thermal_match[] = { + { .compatible = "iio-thermal", }, + { } +}; +MODULE_DEVICE_TABLE(of, iio_thermal_match); + +static struct platform_driver iio_thermal = { + .driver = { + .name = "iio-thermal", + .owner = THIS_MODULE, + .of_match_table = iio_thermal_match, + }, + .probe = iio_thermal_probe, + .remove = iio_thermal_remove, +}; +module_platform_driver(iio_thermal); + +MODULE_DESCRIPTION("Thermal driver for IIO ADCs"); +MODULE_LICENSE("GPL v2");