PCI: imx: Add multi-pd support

On some chips the PCIe and PCIE_PHY blocks are in separate power domains
which can be power-gated independently. The PCI driver needs to handle
this by keeping both domain active.

This is intended for imx6sx where PCIe is in DISPLAY and PCIE_PHY in
its own domain. Defining the DISPLAY domain requires a way for PCIe to
keep it active or it will break when displays are off.

The power-domains on imx6sx are meant to look like this:
	power-domains = <&pd_disp>, <&pd_pci>;
	power-domain-names = "pcie", "pcie_phy";

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
[lorenzo.pieralisi@arm.com: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 2cbef2d7c207..4a307cdf20c8 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -27,6 +27,8 @@
 #include <linux/types.h>
 #include <linux/interrupt.h>
 #include <linux/reset.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
 
 #include "pcie-designware.h"
 
@@ -59,6 +61,11 @@ struct imx6_pcie {
         u32                     tx_swing_low;
         int                     link_gen;
         struct regulator        *vpcie;
+
+        /* power domain for pcie */
+        struct device           *pd_pcie;
+        /* power domain for pcie phy */
+        struct device           *pd_pcie_phy;
 };
 
 /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
@@ -292,6 +299,43 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
         return 1;
 }
 
+static int imx6_pcie_attach_pd(struct device *dev)
+{
+        struct imx6_pcie *imx6_pcie = dev_get_drvdata(dev);
+        struct device_link *link;
+
+        /* Do nothing when in a single power domain */
+        if (dev->pm_domain)
+                return 0;
+
+        imx6_pcie->pd_pcie = dev_pm_domain_attach_by_name(dev, "pcie");
+        if (IS_ERR(imx6_pcie->pd_pcie))
+                return PTR_ERR(imx6_pcie->pd_pcie);
+        link = device_link_add(dev, imx6_pcie->pd_pcie,
+                        DL_FLAG_STATELESS |
+                        DL_FLAG_PM_RUNTIME |
+                        DL_FLAG_RPM_ACTIVE);
+        if (!link) {
+                dev_err(dev, "Failed to add device_link to pcie pd.\n");
+                return -EINVAL;
+        }
+
+        imx6_pcie->pd_pcie_phy = dev_pm_domain_attach_by_name(dev, "pcie_phy");
+        if (IS_ERR(imx6_pcie->pd_pcie_phy))
+                return PTR_ERR(imx6_pcie->pd_pcie_phy);
+
+        device_link_add(dev, imx6_pcie->pd_pcie_phy,
+                        DL_FLAG_STATELESS |
+                        DL_FLAG_PM_RUNTIME |
+                        DL_FLAG_RPM_ACTIVE);
+        if (IS_ERR(link)) {
+                dev_err(dev, "Failed to add device_link to pcie_phy pd: %ld\n", PTR_ERR(link));
+                return PTR_ERR(link);
+        }
+
+        return 0;
+}
+
 static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 {
         struct device *dev = imx6_pcie->pci->dev;
@@ -985,6 +1029,10 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 
         platform_set_drvdata(pdev, imx6_pcie);
 
+        ret = imx6_pcie_attach_pd(dev);
+        if (ret)
+                return ret;
+
         ret = imx6_add_pcie_port(imx6_pcie, pdev);
         if (ret < 0)
                 return ret;