linux-kernel - [PATCH v5 2/2] PCI: brcmstb: Use reset/rearm instead of deassert/assert

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Message-Id: <20210312204556.5387-3-jim2101024@gmail.com>
Date:   Fri, 12 Mar 2021 15:45:55 -0500
From:   Jim Quinlan <jim2101024@...il.com>
To:     Bjorn Helgaas <helgaas@...nel.org>, linux-pci@...r.kernel.org,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        bcm-kernel-feedback-list@...adcom.com, james.quinlan@...adcom.com,
        jim2101024@...il.com
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Jim Quinlan <jquinlan@...adcom.com>,
        linux-rpi-kernel@...ts.infradead.org (moderated list:BROADCOM
        BCM2711/BCM2835 ARM ARCHITECTURE),
        linux-arm-kernel@...ts.infradead.org (moderated list:BROADCOM
        BCM2711/BCM2835 ARM ARCHITECTURE),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v5 2/2] PCI: brcmstb: Use reset/rearm instead of deassert/assert

The Broadcom STB PCIe RC uses a reset control "rescal" for certain chips.
The "rescal" implements a "pulse reset" so using assert/deassert is wrong
for this device.  Instead, we use reset/rearm.  We need to use rearm so
that we can reset it after a suspend/resume cycle; w/o using "rearm", the
"rescal" device will only ever fire once.

Of course for suspend/resume to work we also need to put the reset/rearm
calls in the suspend and resume routines.

Fixes: 740d6c3708a9 ("PCI: brcmstb: Add control of rescal reset")
Signed-off-by: Jim Quinlan <jim2101024@...il.com>
Acked-by: Florian Fainelli <f.fainelli@...il.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index e330e6811f0b..3b35d629035e 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -1148,6 +1148,7 @@ static int brcm_pcie_suspend(struct device *dev)
 
 	brcm_pcie_turn_off(pcie);
 	ret = brcm_phy_stop(pcie);
+	reset_control_rearm(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
 
 	return ret;
@@ -1163,9 +1164,13 @@ static int brcm_pcie_resume(struct device *dev)
 	base = pcie->base;
 	clk_prepare_enable(pcie->clk);
 
+	ret = reset_control_reset(pcie->rescal);
+	if (ret)
+		goto err_disable_clk;
+
 	ret = brcm_phy_start(pcie);
 	if (ret)
-		goto err;
+		goto err_reset;
 
 	/* Take bridge out of reset so we can access the SERDES reg */
 	pcie->bridge_sw_init_set(pcie, 0);
@@ -1180,14 +1185,16 @@ static int brcm_pcie_resume(struct device *dev)
 
 	ret = brcm_pcie_setup(pcie);
 	if (ret)
-		goto err;
+		goto err_reset;
 
 	if (pcie->msi)
 		brcm_msi_set_regs(pcie->msi);
 
 	return 0;
 
-err:
+err_reset:
+	reset_control_rearm(pcie->rescal);
+err_disable_clk:
 	clk_disable_unprepare(pcie->clk);
 	return ret;
 }
@@ -1197,7 +1204,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
 	brcm_msi_remove(pcie);
 	brcm_pcie_turn_off(pcie);
 	brcm_phy_stop(pcie);
-	reset_control_assert(pcie->rescal);
+	reset_control_rearm(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
 }
 
@@ -1278,13 +1285,13 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 		return PTR_ERR(pcie->perst_reset);
 	}
 
-	ret = reset_control_deassert(pcie->rescal);
+	ret = reset_control_reset(pcie->rescal);
 	if (ret)
 		dev_err(&pdev->dev, "failed to deassert 'rescal'\n");
 
 	ret = brcm_phy_start(pcie);
 	if (ret) {
-		reset_control_assert(pcie->rescal);
+		reset_control_rearm(pcie->rescal);
 		clk_disable_unprepare(pcie->clk);
 		return ret;
 	}
-- 
2.17.1