linux-kernel - Re: [PATCH v2 2/6] PCI: brcmstb: Add control of EP voltage regulator(s)

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Message-ID: <154a809d-9320-f0a1-45ad-78af0303a9ac@gmail.com>
Date:   Mon, 30 Nov 2020 13:32:26 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Jim Quinlan <james.quinlan@...adcom.com>,
        linux-pci@...r.kernel.org,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        broonie@...nel.org, bcm-kernel-feedback-list@...adcom.com
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-rpi-kernel@...ts.infradead.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/6] PCI: brcmstb: Add control of EP voltage
 regulator(s)



On 11/30/2020 1:11 PM, Jim Quinlan wrote:
> Control of EP regulators by the RC is needed because of the chicken-and-egg
> situation: although the regulator is "owned" by the EP and would be best
> handled on its driver, the EP cannot be discovered and probed unless its
> regulator is already turned on.
> 
> Signed-off-by: Jim Quinlan <james.quinlan@...adcom.com>
> ---
>  drivers/pci/controller/pcie-brcmstb.c | 38 ++++++++++++++++++++++++++-
>  1 file changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index bea86899bd5d..9d4ac42b3bee 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -23,6 +23,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/pci.h>
>  #include <linux/printk.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/reset.h>
>  #include <linux/sizes.h>
>  #include <linux/slab.h>
> @@ -210,6 +211,10 @@ enum pcie_type {
>  	BCM2711,
>  };
>  
> +static const char * const ep_regulator_names[] = {
> +	"vpcie12v", "vpcie3v3", "vpcie1v8", "vpcie0v9",

Only if you need to re-spin this patch series, I would be keen on
putting each string on its own line, that way when adding a subsequent
regulator name, it is just a matter of an one line d

> +};
> +
>  struct pcie_cfg_data {
>  	const int *offsets;
>  	const enum pcie_type type;
> @@ -287,8 +292,25 @@ struct brcm_pcie {
>  	u32			hw_rev;
>  	void			(*perst_set)(struct brcm_pcie *pcie, u32 val);
>  	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
> +	struct regulator_bulk_data supplies[ARRAY_SIZE(ep_regulator_names)];
>  };
>  
> +static void brcm_set_regulators(struct brcm_pcie *pcie, bool on)
> +{
> +	struct device *dev = pcie->dev;
> +	int ret;
> +
> +	if (on)
> +		ret = regulator_bulk_enable(ARRAY_SIZE(ep_regulator_names),
> +					    pcie->supplies);
> +	else
> +		ret = regulator_bulk_disable(ARRAY_SIZE(ep_regulator_names),
> +					     pcie->supplies);
> +	if (ret)
> +		dev_err(dev, "failed to %s EP regulators\n",
> +			on ? "enable" : "disable");

Should not you propagate the return value to the caller here?
-- 
Florian