From: Guenter Roeck <linux@roeck-us.net>
To: Billy Tsai <billy_tsai@aspeedtech.com>,
"jdelvare@suse.com" <jdelvare@suse.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"krzysztof.kozlowski+dt@linaro.org"
<krzysztof.kozlowski+dt@linaro.org>,
"joel@jms.id.au" <joel@jms.id.au>,
"andrew@aj.id.au" <andrew@aj.id.au>,
"lee@kernel.org" <lee@kernel.org>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
"u.kleine-koenig@pengutronix.de" <u.kleine-koenig@pengutronix.de>,
"corbet@lwn.net" <corbet@lwn.net>,
"p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
"linux-hwmon@vger.kernel.org" <linux-hwmon@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-aspeed@lists.ozlabs.org" <linux-aspeed@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pwm@vger.kernel.org" <linux-pwm@vger.kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>
Cc: kernel test robot <lkp@intel.com>
Subject: Re: [v4 5/5] hwmon: Add Aspeed ast2600 TACH support
Date: Tue, 29 Nov 2022 07:06:03 -0800 [thread overview]
Message-ID: <a0b48e60-59ce-0033-b09f-2f92983753b7@roeck-us.net> (raw)
In-Reply-To: <D5F454FE-9C4B-4B7E-8817-637D5FCC047A@aspeedtech.com>
On 11/28/22 23:08, Billy Tsai wrote:
> On 2022/11/23, 11:45 PM, "Guenter Roeck" <groeck7@gmail.com on behalf of linux@roeck-us.net> wrote:
>
> On 11/22/22 22:16, Billy Tsai wrote:
> > > +The driver provides the following sensor accesses in sysfs:
> > > +=============== ======= =====================================================
> > > +fanX_input ro provide current fan rotation value in RPM as reported
> > > + by the fan to the device.
> > > +fanX_div rw Fan divisor: Supported value are power of 4 (1, 4, 16
> > > + 64, ... 4194304)
>
> > The code doesn't support 1.
>
> The code can support 1.
>
Sorry, leftover from when I misread the code and thought it didn't.
>
> > The existence of a status register makes me wonder what is in there.
> > Does the controller report any errors ? If so, it might be worthwile
> > adding attribute(s) for it.
>
> > > + if (ret)
> > > + return ret;
> > > +
> > > + if (!(val & TACH_ASPEED_FULL_MEASUREMENT))
> > > + return 0;
> > > + rpm = aspeed_tach_val_to_rpm(priv, fan_tach_ch,
> > > + val & TACH_ASPEED_VALUE_MASK);
> > > +
> > > + return rpm;
>
> The status register is the TACH_ASPEED_FULL_MEASUREMENT which is used to indicate that
> the controller doesn't detect the change in tach pin for a long time.
>
> > > +static void aspeed_create_fan_tach_channel(struct aspeed_tach_data *priv,
> > > + u32 tach_ch)
> > > +{
> > > + priv->tach_present[tach_ch] = true;
> > > + priv->tach_channel[tach_ch].limited_inverse = 0;
> > > + regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
> > > + TACH_ASPEED_INVERS_LIMIT,
> > > + priv->tach_channel[tach_ch].limited_inverse ?
> > > + TACH_ASPEED_INVERS_LIMIT :
> > > + 0);
> > > +
> > What is the purpose of the above code ? limited_inverse is always 0.
>
> > > + priv->tach_channel[tach_ch].tach_debounce = DEBOUNCE_3_CLK;
> > > + regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
> > > + TACH_ASPEED_DEBOUNCE_MASK,
> > > + priv->tach_channel[tach_ch].tach_debounce
> > > + << TACH_ASPEED_DEBOUNCE_BIT);
> > > +
> > > + priv->tach_channel[tach_ch].tach_edge = F2F_EDGES;
> > > + regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
> > > + TACH_ASPEED_IO_EDGE_MASK,
> > > + priv->tach_channel[tach_ch].tach_edge
> > > + << TACH_ASPEED_IO_EDGE_BIT);
> > > +
>
> > limited_inverse, tach_debounce, and tach_edge are constants.
> > There is no need to keep constants as per-channel variables.
>
> > > + priv->tach_channel[tach_ch].divisor = DEFAULT_TACH_DIV;
> > > + regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
> > > + TACH_ASPEED_CLK_DIV_T_MASK,
> > > + DIV_TO_REG(priv->tach_channel[tach_ch].divisor)
> > > + << TACH_ASPEED_CLK_DIV_BIT);
> > > +
> > > + priv->tach_channel[tach_ch].threshold = 0;
> > > + regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
> > > + TACH_ASPEED_THRESHOLD_MASK,
> > > + priv->tach_channel[tach_ch].threshold);
> > > +
>
> > The above applies to threshold as well.
>
> The above code is used to retain the adjustable feature of the controller.
> I will remove them until I add the dts property to support them.
>
> > > + }
> > > +
> > > + hwmon = devm_hwmon_device_register_with_info(dev, "aspeed_tach", priv,
> > > + &aspeed_tach_chip_info, NULL);
> > > + ret = PTR_ERR_OR_ZERO(hwmon);
> > > + if (ret)
> > > + return dev_err_probe(dev, ret,
> > > + "Failed to register hwmon device\n");
> > > + return 0;
>
> > Why not return the error ? Either it is an error or it isn't. If it is
> > not an error, dev_err_probe() is not appropriate. If it is, the error
> > should be returned. Either case, if this is on purpose, it needs an
> > explanation.
>
> I have return the return value of the dev_err_probe. Did I miss someting?
>
No, me not having enough coffee when reviewing the code. Sorry for the noise.
Thanks,
Guenter
next prev parent reply other threads:[~2022-11-29 15:06 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-23 6:16 [v4 0/5] Support pwm/tach driver for aspeed ast26xx Billy Tsai
2022-11-23 6:16 ` [v4 1/5] dt-bindings: mfd: Add aspeed pwm-tach binding Billy Tsai
2022-11-23 8:24 ` Krzysztof Kozlowski
2022-11-23 8:27 ` Krzysztof Kozlowski
2022-12-09 0:54 ` Billy Tsai
2022-12-09 7:48 ` Krzysztof Kozlowski
2023-01-06 3:31 ` Billy Tsai
2023-06-08 6:43 ` Krzysztof Kozlowski
[not found] ` <SG2PR06MB3365AE9D075601CB62C6E7F78B50A@SG2PR06MB3365.apcprd06.prod.outlook.com>
2023-06-08 7:20 ` Krzysztof Kozlowski
2022-11-23 15:07 ` Rob Herring
2022-11-23 6:16 ` [v4 2/5] dt-bindings: pwm: Add bindings for aspeed pwm controller Billy Tsai
2022-11-23 8:30 ` Krzysztof Kozlowski
2022-11-23 15:07 ` Rob Herring
2022-11-23 6:16 ` [v4 3/5] dt-bindings: hwmon: Add bindings for aspeed tach controller Billy Tsai
2022-11-23 8:33 ` Krzysztof Kozlowski
2022-11-23 15:21 ` Guenter Roeck
2022-11-23 6:16 ` [v4 4/5] pwm: Add Aspeed ast2600 PWM support Billy Tsai
2022-11-23 8:43 ` Bagas Sanjaya
2023-04-24 10:12 ` Delphine_CC_Chiu/WYHQ/Wiwynn
2022-11-23 6:16 ` [v4 5/5] hwmon: Add Aspeed ast2600 TACH support Billy Tsai
2022-11-23 8:45 ` Bagas Sanjaya
2022-11-23 15:44 ` Guenter Roeck
2022-11-29 7:08 ` Billy Tsai
2022-11-29 15:06 ` Guenter Roeck [this message]
2023-01-17 21:48 ` [v4 0/5] Support pwm/tach driver for aspeed ast26xx Uwe Kleine-König
2023-01-18 1:48 ` Billy Tsai
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