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PCI: imx6: Add regulator support 

Some boards might require to control a regulator to power the PCIe port.

Add support for an optional regulator defined in Device Tree linked in the
PCIe controller under `vpcie-supply`.  If present, the regulator will be
disabled and then enabled as part of the PCIe host initialization process
and will be disabled when shutting down.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
[bhelgaas: use dev_err() instead of pr_err() in
imx6_pcie_assert_core_reset()]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Richard Zhu <hongxing.zhu@nxp.com>
This commit is contained in:
Quentin Schulz 2017-06-08 10:07:42 +02:00 committed by Bjorn Helgaas
parent 769b461fc0
commit c26ebe98a1
2 changed files with 40 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
View File

@ -33,6 +33,10 @@ Optional properties:
- reset-gpio-active-high: If present then the reset sequence using the GPIO
specified in the "reset-gpio" property is reversed (H=reset state,
L=operation state).
- vpcie-supply: Should specify the regulator in charge of PCIe port power.
The regulator will be enabled when initializing the PCIe host and
disabled either as part of the init process or when shutting down the
host.
Additional required properties for imx6sx-pcie:
- clock names: Must include the following additional entries:

37
drivers/pci/dwc/pci-imx6.c
View File

@ -24,6 +24,7 @@
#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>
@ -59,6 +60,7 @@ struct imx6_pcie {
u32 tx_swing_full;
u32 tx_swing_low;
int link_gen;
struct regulator *vpcie;
};
/* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
@ -257,6 +259,8 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
{
struct device *dev = imx6_pcie->pci->dev;
switch (imx6_pcie->variant) {
case IMX7D:
reset_control_assert(imx6_pcie->pciephy_reset);
@ -283,6 +287,14 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 << 16);
break;
}
if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
int ret = regulator_disable(imx6_pcie->vpcie);
if (ret)
dev_err(dev, "failed to disable vpcie regulator: %d\n",
ret);
}
}
static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
@ -349,10 +361,19 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
struct device *dev = pci->dev;
int ret;
if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
ret = regulator_enable(imx6_pcie->vpcie);
if (ret) {
dev_err(dev, "failed to enable vpcie regulator: %d\n",
ret);
return;
}
}
ret = clk_prepare_enable(imx6_pcie->pcie_phy);
if (ret) {
dev_err(dev, "unable to enable pcie_phy clock\n");
return;
goto err_pcie_phy;
}
ret = clk_prepare_enable(imx6_pcie->pcie_bus);
@ -412,6 +433,13 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
clk_disable_unprepare(imx6_pcie->pcie_bus);
err_pcie_bus:
clk_disable_unprepare(imx6_pcie->pcie_phy);
err_pcie_phy:
if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
ret = regulator_disable(imx6_pcie->vpcie);
if (ret)
dev_err(dev, "failed to disable vpcie regulator: %d\n",
ret);
}
}
static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
@ -775,6 +803,13 @@ static int imx6_pcie_probe(struct platform_device *pdev)
if (ret)
imx6_pcie->link_gen = 1;
imx6_pcie->vpcie = devm_regulator_get_optional(&pdev->dev, "vpcie");
if (IS_ERR(imx6_pcie->vpcie)) {
if (PTR_ERR(imx6_pcie->vpcie) == -EPROBE_DEFER)
return -EPROBE_DEFER;
imx6_pcie->vpcie = NULL;
}
platform_set_drvdata(pdev, imx6_pcie);
ret = imx6_add_pcie_port(imx6_pcie, pdev);