Re: [PATCH 02/10] pwm: Add SI-EN SN3112 PWM support

From: Neil Armstrong <neil.armstrong@linaro.org>
To: "Junhao Xie" <bigfoot@classfun.cn>,
	"Konrad Dybcio" <konrad.dybcio@linaro.org>,
	wuxilin123@gmail.com,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Jessica Zhang" <quic_jesszhan@quicinc.com>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	"David Airlie" <airlied@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Tengfei Fan" <quic_tengfan@quicinc.com>,
	"Molly Sophia" <mollysophia379@gmail.com>
Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH 02/10] pwm: Add SI-EN SN3112 PWM support
Date: Thu, 25 Apr 2024 09:57:40 +0200	[thread overview]
Message-ID: <bed21ca2-54c0-473d-b84b-2b404899a050@linaro.org> (raw)
In-Reply-To: <361fc6a0-f0d0-49b2-b885-3b197294ec9f@classfun.cn>

On 25/04/2024 02:57, Junhao Xie wrote:
> On 2024/4/25 03:37, Konrad Dybcio wrote:
>> On 4/24/24 17:29, Xilin Wu via B4 Relay wrote:
>>> From: Junhao Xie <bigfoot@classfun.cn>
>>>
>>> Add a new driver for the SI-EN SN3112 12-channel 8-bit PWM LED controller.
>>>
>>> Signed-off-by: Junhao Xie <bigfoot@classfun.cn>
>>> ---
>> [...]
>>> +    return sn3112_write_reg(priv, SN3112_REG_PWM_EN + reg,
>>> +                priv->pwm_en_reg[reg]);
>>
>> This looks like a weird reimplementation of regmap_update_bits
>>
> 
> We cannot use regmap_update_bits because this chip does not support read command.
> It will discard all read command.

You could use regmap cache with all registers marked as cacheable, but not sure it's worth
doing this.

Neil

> 
>>> +}
>>> +
> [...]
>>
>> devm_pwmchip_add?
>>
>> Konrad
> 
> Thank you for your reply, I will fix them.
> 