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PCI: tegra: Make sure the PCIe PLL is really reset

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Depending on the prior state of the controller, the PLL reset may not be
pulsed.  Clear the register bit and set it after a small delay to ensure
that the PLL is really reset.

Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Eric Yuen <eyuen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Eric Yuen 2014-08-26 17:11:37 +02:00 committed by Bjorn Helgaas
parent 8d41794c6f
commit ec73276204
1 changed files with 7 additions and 0 deletions
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7
drivers/pci/host/pci-tegra.c
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@ -849,6 +849,13 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie)
value |= PADS_PLL_CTL_REFCLK_INTERNAL_CML | soc->tx_ref_sel;
pads_writel(pcie, value, soc->pads_pll_ctl);
/* reset PLL */
value = pads_readl(pcie, soc->pads_pll_ctl);
value &= ~PADS_PLL_CTL_RST_B4SM;
pads_writel(pcie, value, soc->pads_pll_ctl);
usleep_range(20, 100);
/* take PLL out of reset */
value = pads_readl(pcie, soc->pads_pll_ctl);
value |= PADS_PLL_CTL_RST_B4SM;