linux-kernel - Re: [RFC PATCH 14/15] WIP: PCI: qcom: use pwrseq to power up bus devices

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Date:   Thu, 19 Aug 2021 16:44:26 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     Andy Gross <agross@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Stanimir Varbanov <svarbanov@...sol.com>,
        linux-arm-msm@...r.kernel.org, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        ath10k@...ts.infradead.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [RFC PATCH 14/15] WIP: PCI: qcom: use pwrseq to power up bus
 devices

On Mon 16 Aug 17:55 PDT 2021, Dmitry Baryshkov wrote:

> Use bus-pwrseq device tree node to power up the devices on the bus. This
> is to be rewritten with the proper code parsing the device tree and
> powering up individual devices.
> 

How about describing the PCI device in DT and having the PCIe controller
dig it up up from there? Although we won't have a struct device until
later, so perhaps we need the of-based pwrseq_get() for that.

Regards,
Bjorn

> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 13 +++++++++++++
>  drivers/power/pwrseq/pwrseq_qca.c      |  1 +
>  2 files changed, 14 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 8a7a300163e5..a60d41fbcd6f 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -23,6 +23,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/platform_device.h>
>  #include <linux/phy/phy.h>
> +#include <linux/pwrseq/consumer.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/reset.h>
>  #include <linux/slab.h>
> @@ -1467,6 +1468,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  	struct pcie_port *pp;
>  	struct dw_pcie *pci;
>  	struct qcom_pcie *pcie;
> +	struct pwrseq *pwrseq;
>  	int ret;
>  
>  	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> @@ -1520,6 +1522,17 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  
>  	pp->ops = &qcom_pcie_dw_ops;
>  
> +	pwrseq = devm_pwrseq_get_optional(dev, "bus");
> +	if (IS_ERR(pwrseq)) {
> +		ret = PTR_ERR(pwrseq);
> +		goto err_pm_runtime_put;
> +	}
> +	if (pwrseq) {
> +		ret = pwrseq_full_power_on(pwrseq);
> +		if (ret)
> +			goto err_pm_runtime_put;
> +	}
> +
>  	ret = phy_init(pcie->phy);
>  	if (ret) {
>  		pm_runtime_disable(&pdev->dev);
> diff --git a/drivers/power/pwrseq/pwrseq_qca.c b/drivers/power/pwrseq/pwrseq_qca.c
> index 3421a4821126..4107f0a9c05d 100644
> --- a/drivers/power/pwrseq/pwrseq_qca.c
> +++ b/drivers/power/pwrseq/pwrseq_qca.c
> @@ -1,3 +1,4 @@
> +#define DEBUG
>  // SPDX-License-Identifier: GPL-2.0-only
>  /*
>   * Copyright (c) 2021, Linaro Ltd.
> -- 
> 2.30.2
>