| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <3309a9f1f5848681d0acf3bfdf9b6525fc88e1bc.camel@apitzsch.eu>
Date: Sat, 04 May 2024 20:27:11 +0200
From: André Apitzsch <git@...tzsch.eu>
To: Lee Jones <lee@...nel.org>
Cc: Pavel Machek <pavel@....cz>, Rob Herring <robh@...nel.org>, Krzysztof
Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley
<conor+dt@...nel.org>, Kees Cook <keescook@...omium.org>, "Gustavo A. R.
Silva" <gustavoars@...nel.org>, Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>, linux-leds@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-hardening@...r.kernel.org, linux-arm-msm@...r.kernel.org,
~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] leds: sy7802: Add support for Silergy SY7802
flash LED controller
Am Freitag, dem 03.05.2024 um 08:19 +0100 schrieb Lee Jones:
> On Thu, 11 Apr 2024, Lee Jones wrote:
>
> > On Mon, 01 Apr 2024, André Apitzsch via B4 Relay wrote:
> >
> > > From: André Apitzsch <git@...tzsch.eu>
> > >
> > > Add support for SY7802 flash LED controller. It can support up to
> > > 1.8A
> > > flash current.
> >
> > This is a very small commit message for a 500+ line change!
> >
> > Please, tell us more.
> >
> > > Signed-off-by: André Apitzsch <git@...tzsch.eu>
> > > ---
> > > drivers/leds/flash/Kconfig | 11 +
> > > drivers/leds/flash/Makefile | 1 +
> > > drivers/leds/flash/leds-sy7802.c | 532
> > > +++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 544 insertions(+)
> > >
> > > diff --git a/drivers/leds/flash/Kconfig
> > > b/drivers/leds/flash/Kconfig
> > > index 809b6d98bb3e..f39f0bfe6eef 100644
> > > --- a/drivers/leds/flash/Kconfig
> > > +++ b/drivers/leds/flash/Kconfig
> > > @@ -121,4 +121,15 @@ config LEDS_SGM3140
> > > This option enables support for the SGM3140 500mA
> > > Buck/Boost Charge
> > > Pump LED Driver.
> > >
> > > +config LEDS_SY7802
> > > + tristate "LED support for the Silergy SY7802"
> > > + depends on I2C && OF
> > > + depends on GPIOLIB
> > > + select REGMAP_I2C
> > > + help
> > > + This option enables support for the SY7802 flash LED
> > > controller.
> > > + SY7802 includes torch and flash functions with
> > > programmable current.
> > > +
> > > + This driver can be built as a module, it will be
> > > called "leds-sy7802".
> > > +
> > > endif # LEDS_CLASS_FLASH
> > > diff --git a/drivers/leds/flash/Makefile
> > > b/drivers/leds/flash/Makefile
> > > index 91d60a4b7952..48860eeced79 100644
> > > --- a/drivers/leds/flash/Makefile
> > > +++ b/drivers/leds/flash/Makefile
> > > @@ -11,3 +11,4 @@ obj-$(CONFIG_LEDS_QCOM_FLASH) += leds-qcom-
> > > flash.o
> > > obj-$(CONFIG_LEDS_RT4505) += leds-rt4505.o
> > > obj-$(CONFIG_LEDS_RT8515) += leds-rt8515.o
> > > obj-$(CONFIG_LEDS_SGM3140) += leds-sgm3140.o
> > > +obj-$(CONFIG_LEDS_SY7802) += leds-sy7802.o
> > > diff --git a/drivers/leds/flash/leds-sy7802.c
> > > b/drivers/leds/flash/leds-sy7802.c
> > > new file mode 100644
> > > index 000000000000..c03a571b0e08
> > > --- /dev/null
> > > +++ b/drivers/leds/flash/leds-sy7802.c
> > > @@ -0,0 +1,532 @@
>
> [...]
>
> > > +static int sy7802_torch_brightness_set(struct led_classdev
> > > *lcdev, enum led_brightness level)
> >
> > s/level/brightness/
> >
> > > +{
> > > + struct sy7802_led *led = container_of(lcdev, struct
> > > sy7802_led, flash.led_cdev);
> > > + u32 led_enable_mask = led->led_no == SY7802_LED_JOINT ?
> > > SY7802_LEDS_MASK_ALL :
> > > + SY7802_LEDS_MASK(led->led_no);
> >
> > Do all of the fancy multi-line assignment outside of the
> > declaration block.
> >
> > > + u32 enable_mask = SY7802_MODE_MASK | led_enable_mask;
> > > + u32 val = level ? led_enable_mask : SY7802_MODE_OFF;
> > > + struct sy7802 *chip = led->chip;
> > > + u32 curr;
> >
> > This is a temporary placeholder for fled_torch_used, right?
> >
> > fled_torch_used_tmp? Sometimes abbreviated to tmp.
> >
> > > + u32 mask;
> >
> > That's a lot of masks. Which one is this?
> >
> > > + int ret;
> > > +
> > > + mutex_lock(&chip->mutex);
> > > +
> > > + /*
> > > + * There is only one set of flash control logic, and
> > > this flag is used to check if 'strobe'
> >
> > The ',' before 'and' is superfluous.
> >
> > > + * is currently being used.
> > > + */
> >
> > Doesn't the variable name kind of imply this?
> >
> > > + if (chip->fled_strobe_used) {
> > > + dev_warn(chip->dev, "Please disable strobe first
> > > [%d]\n", chip->fled_strobe_used);
> >
> > "Cannot set torch brightness whilst strobe is enabled"
> >
> > > + ret = -EBUSY;
> > > + goto unlock;
> > > + }
> > > +
> > > + if (level)
> > > + curr = chip->fled_torch_used | BIT(led->led_no);
> > > + else
> > > + curr = chip->fled_torch_used & ~BIT(led-
> > > >led_no);
> > > +
> > > + if (curr)
> > > + val |= SY7802_MODE_TORCH;
> > > +
> > > + /* Torch needs to be disabled first to apply new
> > > brightness */
> >
> > "Disable touch to apply brightness"
> >
> > > + ret = regmap_update_bits(chip->regmap,
> > > SY7802_REG_ENABLE, SY7802_MODE_MASK,
> > > + SY7802_MODE_OFF);
> > > + if (ret)
> > > + goto unlock;
> > > +
> > > + mask = led->led_no == SY7802_LED_JOINT ?
> > > SY7802_TORCH_CURRENT_MASK_ALL :
> >
> > Why not just use led->led_no in place of mask?
>
> mask and led->led_no are assigned the same value from this point on.
Thanks for the clarification.
How to you come to the conclusion that mask and led->led_no are
assigned the same value from this point on?
The value of led->led_no is used here only as part of the if condition
(led->led_no == SY7802_LED_JOINT) and not assigned to mask.
>
> > Easier to read if you drop SY7802_TORCH_CURRENT_MASK_ALL to its own
> > line.
> >
> > > + SY7802_TORCH_CURRENT_MASK(led->led_no);
> > > +
> > > + /* Register expects brightness between 0 and
> > > MAX_BRIGHTNESS - 1 */
> > > + if (level)
> > > + level -= 1;
> > > +
> > > + level |= (level << SY7802_TORCH_CURRENT_SHIFT);
> > > +
> > > + ret = regmap_update_bits(chip->regmap,
> > > SY7802_REG_TORCH_BRIGHTNESS, mask, level);
>
> So why not kill the single-use 'mask' variable and use a cast version
> of led->led_no here instead?
>
> > > + if (ret)
> > > + goto unlock;
> > > +
> > > + ret = regmap_update_bits(chip->regmap,
> > > SY7802_REG_ENABLE, enable_mask, val);
> > > + if (ret)
> > > + goto unlock;
> > > +
> > > + chip->fled_torch_used = curr;
> > > +
> > > +unlock:
> > > + mutex_unlock(&chip->mutex);
> > > + return ret;
> > > +}
>
Powered by blists - more mailing lists