On 5/21/2020 2:48 PM, Jim Quinlan wrote:

On Wed, May 20, 2020 at 3:27 AM Philipp Zabel [off-list ref] wrote:

quoted

Hi Jim,

On Tue, May 19, 2020 at 04:34:05PM -0400, Jim Quinlan wrote:

quoted

From: Jim Quinlan <redacted>

Some STB chips have a special purpose reset controller named
RESCAL (reset calibration).  This commit adds the control
of RESCAL as well as the ability to start and stop its
operation for PCIe HW.

Signed-off-by: Jim Quinlan <redacted>
---
 drivers/pci/controller/pcie-brcmstb.c | 81 ++++++++++++++++++++++++++-
 1 file changed, 80 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 2c470104ba38..0787e8f6f7e5 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c

[...]

quoted

@@ -1100,6 +1164,21 @@ static int brcm_pcie_probe(struct platform_device *pdev)
              dev_err(&pdev->dev, "could not enable clock\n");
              return ret;
      }
+     pcie->rescal = devm_reset_control_get_shared(&pdev->dev, "rescal");
+     if (IS_ERR(pcie->rescal)) {
+             if (PTR_ERR(pcie->rescal) == -EPROBE_DEFER)
+                     return -EPROBE_DEFER;
+             pcie->rescal = NULL;

This is effectively an optional reset control, so it is better to use:
↵
        pcie->rescal = devm_reset_control_get_optional_shared(&pdev->dev,
                                                              "rescal");↵
        if (IS_ERR(pcie->rescal))
                return PTR_ERR(pcie->rescal);

quoted

+     } else {
+             ret = reset_control_deassert(pcie->rescal);
+             if (ret)
+                     dev_err(&pdev->dev, "failed to deassert 'rescal'\n");
+     }

reset_control_* can handle rstc == NULL parameters for optional reset
controls, so this can be done unconditionally:

        ret = reset_control_deassert(pcie->rescal);↵
        if (ret)↵
                dev_err(&pdev->dev, "failed to deassert 'rescal'\n");↵

Is rescal handled by the reset-brcmstb-rescal driver? Since that only
implements the .reset op, I would expect reset_control_reset() here.

Where exactly?  "reset.h" says that "Calling reset_control_rese()t is
not allowed on a shared reset control." so I'm not sure why  you would
want me to invoke it.

Yes this is handled by drivers/reset/reset-brcmstb-rescal.c which only
implements a .reset() callback, what would be the appropriate API usage
here given that this is a shared reset between AHCI and PCIe, should
drivers/reset/reset-brcmstb-rescal.c not implement a .reset() callback
and .assert() callback instead?

quoted

Otherwise this looks like it'd be missing a reset_control_assert in
remove.

I can add this.
Thanks,
Jim

quoted

regards
Philipp

-- 
Florian

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