linux-kernel - Re: [PATCH 3/4] phy: cadence-torrent: Do not configure SERDES if it's already configured

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Date:   Tue, 30 Mar 2021 15:27:22 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Swapnil Kashinath Jakhade <sjakhade@...ence.com>,
        Vinod Koul <vkoul@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Lokesh Vutla <lokeshvutla@...com>,
        "linux-phy@...ts.infradead.org" <linux-phy@...ts.infradead.org>
Subject: Re: [PATCH 3/4] phy: cadence-torrent: Do not configure SERDES if it's
 already configured

Hi Swapnil,

On 18/03/21 3:25 pm, Swapnil Kashinath Jakhade wrote:
> 
> 
>> -----Original Message-----
>> From: Kishon Vijay Abraham I <kishon@...com>
>> Sent: Wednesday, March 10, 2021 9:25 PM
>> To: Kishon Vijay Abraham I <kishon@...com>; Vinod Koul
>> <vkoul@...nel.org>; Rob Herring <robh+dt@...nel.org>; Philipp Zabel
>> <p.zabel@...gutronix.de>; Swapnil Kashinath Jakhade
>> <sjakhade@...ence.com>
>> Cc: linux-kernel@...r.kernel.org; devicetree@...r.kernel.org; Lokesh Vutla
>> <lokeshvutla@...com>; linux-phy@...ts.infradead.org
>> Subject: [PATCH 3/4] phy: cadence-torrent: Do not configure SERDES if it's
>> already configured
>>
>> EXTERNAL MAIL
>>
>>
>> Do not configure torrent SERDES if it's already configured.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
>> ---
>>  drivers/phy/cadence/phy-cadence-torrent.c | 32 ++++++++++++++++-------
>>  1 file changed, 22 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/phy/cadence/phy-cadence-torrent.c
>> b/drivers/phy/cadence/phy-cadence-torrent.c
>> index ab51c4bf7b30..5ee1657f5a1c 100644
>> --- a/drivers/phy/cadence/phy-cadence-torrent.c
>> +++ b/drivers/phy/cadence/phy-cadence-torrent.c
>> @@ -371,6 +371,10 @@ static const struct phy_ops cdns_torrent_phy_ops =
>> {
>>  	.owner		= THIS_MODULE,
>>  };
>>
>> +static const struct phy_ops noop_ops = {
>> +	.owner		= THIS_MODULE,
>> +};
>> +
>>  struct cdns_reg_pairs {
>>  	u32 val;
>>  	u32 off;
>> @@ -2306,6 +2310,7 @@ static int cdns_torrent_phy_probe(struct
>> platform_device *pdev)
>>  	struct device_node *child;
>>  	int ret, subnodes, node = 0, i;
>>  	u32 total_num_lanes = 0;
>> +	int already_configured;
>>  	u8 init_dp_regmap = 0;
>>  	u32 phy_type;
>>
>> @@ -2344,16 +2349,20 @@ static int cdns_torrent_phy_probe(struct
>> platform_device *pdev)
>>  	if (ret)
>>  		return ret;
>>
>> -	ret = cdns_torrent_reset(cdns_phy);
>> -	if (ret)
>> -		goto clk_cleanup;
>> +	regmap_field_read(cdns_phy->phy_pma_cmn_ctrl_1,
>> &already_configured);
>>
>> -	ret = cdns_torrent_clk(cdns_phy);
>> -	if (ret)
>> -		goto clk_cleanup;
>> +	if (!already_configured) {
>> +		ret = cdns_torrent_reset(cdns_phy);
>> +		if (ret)
>> +			goto clk_cleanup;
>> +
>> +		ret = cdns_torrent_clk(cdns_phy);
>> +		if (ret)
>> +			goto clk_cleanup;
>>
> Should if (!already_configured) be checked while calling clk_disable_unprepare()?

Both clk_unprepare() and clk_disable() checks for passed clk for ERR or
NULL. So don't think it's necessary to have !already_configured check.
> Otherwise,
> Reviewed-by: Swapnil Jakhade <sjakhade@...ence.com>

Thanks
Kishon

> 
> Thanks & regards,
> Swapnil
> 
>> -	/* Enable APB */
>> -	reset_control_deassert(cdns_phy->apb_rst);
>> +		/* Enable APB */
>> +		reset_control_deassert(cdns_phy->apb_rst);
>> +	}
>>
>>  	for_each_available_child_of_node(dev->of_node, child) {
>>  		struct phy *gphy;
>> @@ -2423,7 +2432,10 @@ static int cdns_torrent_phy_probe(struct
>> platform_device *pdev)
>>  		of_property_read_u32(child, "cdns,ssc-mode",
>>  				     &cdns_phy->phys[node].ssc_mode);
>>
>> -		gphy = devm_phy_create(dev, child,
>> &cdns_torrent_phy_ops);
>> +		if (!already_configured)
>> +			gphy = devm_phy_create(dev, child,
>> &cdns_torrent_phy_ops);
>> +		else
>> +			gphy = devm_phy_create(dev, child, &noop_ops);
>>  		if (IS_ERR(gphy)) {
>>  			ret = PTR_ERR(gphy);
>>  			goto put_child;
>> @@ -2507,7 +2519,7 @@ static int cdns_torrent_phy_probe(struct
>> platform_device *pdev)
>>  		goto put_lnk_rst;
>>  	}
>>
>> -	if (cdns_phy->nsubnodes > 1) {
>> +	if (cdns_phy->nsubnodes > 1 && !already_configured) {
>>  		ret = cdns_torrent_phy_configure_multilink(cdns_phy);
>>  		if (ret)
>>  			goto put_lnk_rst;
>> --
>> 2.17.1
>