linux-kernel - Re: [PATCH RFC v3 3/4] spmi: pmic-arb: Make core resources acquiring a version operation

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Message-ID: <5e878fd9-8215-499d-ac1c-191cb5bfe798@linaro.org>
Date: Wed, 14 Feb 2024 22:44:55 +0100
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Abel Vesa <abel.vesa@...aro.org>
Cc: Stephen Boyd <sboyd@...nel.org>, Matthias Brugger
 <matthias.bgg@...il.com>, Bjorn Andersson <andersson@...nel.org>,
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Neil Armstrong <neil.armstrong@...aro.org>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 Srini Kandagatla <srinivas.kandagatla@...aro.org>,
 Johan Hovold <johan@...nel.org>, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
 linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH RFC v3 3/4] spmi: pmic-arb: Make core resources acquiring
 a version operation

On 14.02.2024 22:36, Abel Vesa wrote:
> On 24-02-14 22:18:33, Konrad Dybcio wrote:
>> On 14.02.2024 22:13, Abel Vesa wrote:
>>> Rather than setting up the core, obsrv and chnls in probe by using
>>> version specific conditionals, add a dedicated "get_core_resources"
>>> version specific op and move the acquiring in there.
>>>
>>> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
>>> ---
>>>  drivers/spmi/spmi-pmic-arb.c | 111 ++++++++++++++++++++++++++++++-------------
>>>  1 file changed, 78 insertions(+), 33 deletions(-)
>>>
>>> diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
>>> index 23939c0d225f..489556467a4c 100644
>>> --- a/drivers/spmi/spmi-pmic-arb.c
>>> +++ b/drivers/spmi/spmi-pmic-arb.c
>>> @@ -203,6 +203,7 @@ struct spmi_pmic_arb {
>>>   */
>>>  struct pmic_arb_ver_ops {
>>>  	const char *ver_str;
>>> +	int (*get_core_resources)(struct platform_device *pdev, void __iomem *core);
>>>  	int (*init_apid)(struct spmi_pmic_arb *pmic_arb, int index);
>>>  	int (*ppid_to_apid)(struct spmi_pmic_arb *pmic_arb, u16 ppid);
>>>  	/* spmi commands (read_cmd, write_cmd, cmd) functionality */
>>> @@ -956,6 +957,19 @@ static int pmic_arb_init_apid_min_max(struct spmi_pmic_arb *pmic_arb)
>>>  	return 0;
>>>  }
>>>  
>>> +static int pmic_arb_get_core_resources_v1(struct platform_device *pdev,
>>> +					  void __iomem *core)
>>> +{
>>> +	struct spmi_pmic_arb *pmic_arb = platform_get_drvdata(pdev);
>>> +
>>> +	pmic_arb->wr_base = core;
>>> +	pmic_arb->rd_base = core;
>>> +
>>> +	pmic_arb->max_periphs = PMIC_ARB_MAX_PERIPHS;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  static int pmic_arb_init_apid_v1(struct spmi_pmic_arb *pmic_arb, int index)
>>>  {
>>>  	u32 *mapping_table;
>>> @@ -1063,6 +1077,41 @@ static u16 pmic_arb_find_apid(struct spmi_pmic_arb *pmic_arb, u16 ppid)
>>>  	return apid;
>>>  }
>>>  
>>> +static int pmic_arb_get_obsrvr_chnls_v2(struct platform_device *pdev)
>>> +{
>>> +	struct spmi_pmic_arb *pmic_arb = platform_get_drvdata(pdev);
>>> +	struct device *dev = &pdev->dev;
>>> +	struct resource *res;
>>> +
>>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>
>> It's no longer indented to deep, no need to keep such aggressive wrapping
>>
> 
> The pmic_arb_get_obsrvr_chnls_v2 is used by both:
> pmic_arb_get_core_resources_v2
> pmic_arb_get_core_resources_v7

I meant line wrapping

> 
>>> +					   "obsrvr");
>>> +	pmic_arb->rd_base = devm_ioremap(dev, res->start,
>>> +					 resource_size(res));
>>> +	if (IS_ERR(pmic_arb->rd_base))
>>> +		return PTR_ERR(pmic_arb->rd_base);
>>> +
>>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>> +					   "chnls");
>>> +	pmic_arb->wr_base = devm_ioremap(dev, res->start,
>>> +					 resource_size(res));
>>> +	if (IS_ERR(pmic_arb->wr_base))
>>> +		return PTR_ERR(pmic_arb->wr_base);
>>
>> Could probably make it "devm_platform_get_and_ioremap_resource "
> 
> The reason this needs to stay as is is because of reason explained by
> the following comment found in probe:
> 
> /*                                                                           
>  * Please don't replace this with devm_platform_ioremap_resource() or        
>  * devm_ioremap_resource().  These both result in a call to                  
>  * devm_request_mem_region() which prevents multiple mappings of this        
>  * register address range.  SoCs with PMIC arbiter v7 may define two         
>  * arbiter devices, for the two physical SPMI interfaces, which  share       
>  * some register address ranges (i.e. "core", "obsrvr", and "chnls").        
>  * Ensure that both devices probe successfully by calling devm_ioremap()     
>  * which does not result in a devm_request_mem_region() call.                
>  */                                                                          
> 
> Even though, AFAICT, there is no platform that adds a second node for
> the second bus, currently, in mainline, we should probably allow the
> "legacy" approach to still work.

OK right, let's keep it.

Konrad