linux-kernel - Re: [PATCH 12/13] media: qcom: camss: Add CSID Gen3 support for sm8550

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Message-ID: <4bd0c70f-f425-4cb1-af77-17faa6af2fd6@linaro.org>
Date: Fri, 16 Aug 2024 15:49:53 +0100
From: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To: Depeng Shao <quic_depengs@...cinc.com>, rfoss@...nel.org,
 todor.too@...il.com, mchehab@...nel.org, robh@...nel.org,
 krzk+dt@...nel.org, conor+dt@...nel.org
Cc: linux-arm-msm@...r.kernel.org, linux-media@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 kernel@...cinc.com, Yongsheng Li <quic_yon@...cinc.com>
Subject: Re: [PATCH 12/13] media: qcom: camss: Add CSID Gen3 support for
 sm8550

On 12/08/2024 15:41, Depeng Shao wrote:
> +	writel(1, csid->base + CSID_TOP_IRQ_CLEAR);
> +	writel(1, csid->base + CSID_IRQ_CMD);

CSID_IRQ_CMD bit(0) = CMD_CLEAR

> +	writel(1, csid->base + CSID_TOP_IRQ_MASK);
> +
> +	for (i = 0; i < MSM_CSID_MAX_SRC_STREAMS; i++)
> +		if (csid->phy.en_vc & BIT(i)) {
> +			writel(BIT(BUF_DONE_IRQ_STATUS_RDI_OFFSET + i),
> +						csid->base + CSID_BUF_DONE_IRQ_CLEAR);
> +			writel(0x1 << IRQ_CMD_CLEAR, csid->base + CSID_IRQ_CMD);

CSID_IRQ_CMD bit(0) = CMD_CLEAR

and again here.

> +			writel(BIT(BUF_DONE_IRQ_STATUS_RDI_OFFSET + i),
> +						csid->base + CSID_BUF_DONE_IRQ_MASK);
> +		}

re: previous comments

1. Please define bits so that'd be

#define CSID_IRQ_CMD_CLEAR	BIT(0)
writel(CSID_IRQ_CMD_CLEAR, csid->base + CSID_IRQ_CMD);

There's no value in circumscribing the meaning of bitfields in upstream 
code, we just make our own lives easier by having self-documenting code.

TL;DR please name your bits - a blanket statement for the series.

2. And as mentioned above, you don't need to execute that clear n times 
in a loop. Just do it once at the top of the routine.

---
bod