Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758370AbbBFSiP (ORCPT ); Fri, 6 Feb 2015 13:38:15 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:49520 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758188AbbBFSiL (ORCPT ); Fri, 6 Feb 2015 13:38:11 -0500 Date: Fri, 6 Feb 2015 10:36:57 -0800 From: Guenter Roeck To: Lukasz Majewski Cc: Eduardo Valentin , Kamil Debski , Jean Delvare , Kukjin Kim , lm-sensors@lm-sensors.org, Linux PM list , "linux-samsung-soc@vger.kernel.org" , devicetree@vger.kernel.org, Lukasz Majewski , Kukjin Kim , linux-kernel@vger.kernel.org, Sjoerd Simons , Abhilash Kesavan , Abhilash Kesavan Subject: Re: [PATCH v3 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree Message-ID: <20150206183657.GB25410@roeck-us.net> References: <1418897591-18332-1-git-send-email-l.majewski@samsung.com> <1423241948-31981-1-git-send-email-l.majewski@samsung.com> <1423241948-31981-8-git-send-email-l.majewski@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1423241948-31981-8-git-send-email-l.majewski@samsung.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-CTCH-PVer: 0000001 X-CTCH-Spam: Unknown X-CTCH-VOD: Unknown X-CTCH-Flags: 0 X-CTCH-RefID: str=0001.0A020205.54D50A13.0059,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.001 X-CTCH-ScoreCust: 0.000 X-CTCH-Rules: C_4847, X-CTCH-SenderID: linux@roeck-us.net X-CTCH-SenderID-Flags: 0 X-CTCH-SenderID-TotalMessages: 12 X-CTCH-SenderID-TotalSpam: 0 X-CTCH-SenderID-TotalSuspected: 0 X-CTCH-SenderID-TotalConfirmed: 0 X-CTCH-SenderID-TotalBulk: 0 X-CTCH-SenderID-TotalVirus: 0 X-CTCH-SenderID-TotalRecipients: 0 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-Get-Message-Sender-Via: bh-25.webhostbox.net: mailgid no entry from get_relayhosts_entry X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2866 Lines: 77 On Fri, Feb 06, 2015 at 05:59:07PM +0100, Lukasz Majewski wrote: > This patch provides code for reading PWM FAN configuration data via > device tree. The pwm-fan can work with full speed when configuration > is not provided. However, errors are propagated when wrong DT bindings > are found. > Additionally the struct pwm_fan_ctx has been extended. > > Signed-off-by: Lukasz Majewski > --- > Changes for v2: > - Rename pwm_fan_max_states to pwm_fan_cooling_levels > - Moving pwm_fan_of_get_cooling_data() call after setting end enabling PWM FAN > - pwm_fan_of_get_cooling_data() now can fail - preserving old behaviour > - Remove unnecessary dev_err() call > Changes for v3: > - Patch's headline has been reedited > - pwm_fan_of_get_cooling_data() return code is now being checked. > - of_property_count_elems_of_size() is now used instead of_find_property() > - More verbose patch description added > --- > drivers/hwmon/pwm-fan.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 53 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 870e100..f3f5843 100644 > --- a/drivers/hwmon/pwm-fan.c > +++ b/drivers/hwmon/pwm-fan.c > @@ -30,7 +30,10 @@ > struct pwm_fan_ctx { > struct mutex lock; > struct pwm_device *pwm; > - unsigned char pwm_value; > + unsigned int pwm_value; > + unsigned int pwm_fan_state; > + unsigned int pwm_fan_max_state; > + unsigned int *pwm_fan_cooling_levels; > }; > > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > @@ -100,6 +103,50 @@ static struct attribute *pwm_fan_attrs[] = { > > ATTRIBUTE_GROUPS(pwm_fan); > > +int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) > +{ > + struct device_node *np = dev->of_node; > + int num, i, ret; > + > + ret = of_property_count_elems_of_size(np, "cooling-levels", > + sizeof(u32)); > + > + if (ret == -EINVAL) { > + dev_err(dev, "Property 'cooling-levels' not found\n"); > + return 0; Returning 0 is obviously not an error, otherwise you would not return 0 here. So dev_err is wrong. Also, the message itself is wrong; the property may well be there but have a wrong size. > + } > + > + if (ret <= 0) { > + dev_err(dev, "Wrong data!\n"); > + return ret; > + } This will result in the driver failing to load if devicetree is not configured (of_property_count_elems_of_size will return -ENOSYS). This is not acceptable. Also, if the call returns 0 you don't return an error but display a "Wrong data!" error message. Either it is an error or it is not, but not both. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/