Some PCIe ports gate power to the slot. In order to prevent system lockup,
these boards must enable power to the slot before attempting communication
over the PCI bus.
Signed-off-by: Sean Cross <x...@kosagi.com>
---
.../devicetree/bindings/pci/fsl,imx6q-pcie.txt | 3 +++
drivers/pci/host/pci-imx6.c | 27 ++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
index 6fbba53..a806b68 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
@@ -13,6 +13,9 @@ Required properties:
- clock-names: Must include the following additional entries:
- "pcie_phy"
+Optional properties:
+- bus-supply: A regulator that controls power to the entire bus
+
Example:
pcie@0x01000000 {
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 69202d1..8e4f957 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -22,6 +22,7 @@
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
#include <linux/resource.h>
#include <linux/signal.h>
#include <linux/types.h>
@@ -39,6 +40,7 @@ struct imx6_pcie {
struct pcie_port pp;
struct regmap *iomuxc_gpr;
void __iomem *mem_base;
+ struct regulator *bus_supply;
};
/* PCIe Root Complex registers (memory-mapped) */
@@ -523,6 +525,7 @@ static struct pcie_host_ops imx6_pcie_host_ops = {
static int __init imx6_add_pcie_port(struct pcie_port *pp,
struct platform_device *pdev)
{
+ struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
int ret;
if (IS_ENABLED(CONFIG_PCI_MSI)) {
@@ -544,9 +547,22 @@ static int __init imx6_add_pcie_port(struct pcie_port *pp,
pp->root_bus_nr = -1;
pp->ops = &imx6_pcie_host_ops;
+ if (imx6_pcie->bus_supply) {
+ ret = regulator_enable(imx6_pcie->bus_supply);
+ if (ret) {
+ dev_err(pp->dev,
+ "unable to enable bus supply: %d\n", ret);
+ return ret;
+ }
+ }
+
ret = dw_pcie_host_init(pp);
if (ret) {
dev_err(&pdev->dev, "failed to initialize host\n");
+
+ if (imx6_pcie->bus_supply)
+ regulator_disable(imx6_pcie->bus_supply);
+
return ret;
}
@@ -588,6 +604,17 @@ static int __init imx6_pcie_probe(struct platform_device
*pdev)
}
}
+ /* Fetch bus supply */
+ imx6_pcie->bus_supply = devm_regulator_get_optional(&pdev->dev, "bus");
+ if (IS_ERR(imx6_pcie->bus_supply)) {
+ ret = PTR_ERR(imx6_pcie->bus_supply);
+ if (ret == -EPROBE_DEFER)
+ return ret;
+
+ dev_err(&pdev->dev, "unable to get bus-supply\n");
+ return ret;
+ }
+
/* Fetch clocks */
imx6_pcie->pcie_phy = devm_clk_get(&pdev->dev, "pcie_phy");
if (IS_ERR(imx6_pcie->pcie_phy)) {
--
2.1.3
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