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

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Message-ID: <Zc3Y2YmjZ1gYjmmq@linaro.org>
Date: Thu, 15 Feb 2024 11:26:49 +0200
From: Abel Vesa <abel.vesa@...aro.org>
To: Konrad Dybcio <konrad.dybcio@...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 24-02-14 22:44:55, Konrad Dybcio wrote:
> 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

Oh, ok. Will do.

> 
> > 
> >>> +					   "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