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Subject[PATCH v2 3/4] PCI: imx: Add multi-pd support
Date
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
it's 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>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
---
drivers/pci/controller/dwc/pci-imx6.c | 48 +++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 6171171db1fc..a482f86b02e6 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -25,10 +25,12 @@
#include <linux/resource.h>
#include <linux/signal.h>
#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"

#define to_imx6_pcie(x) dev_get_drvdata((x)->dev)

@@ -57,10 +59,15 @@ struct imx6_pcie {
u32 tx_deemph_gen2_6db;
u32 tx_swing_full;
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 */
#define PHY_PLL_LOCK_WAIT_MAX_RETRIES 2000
#define PHY_PLL_LOCK_WAIT_USLEEP_MIN 50
@@ -290,10 +297,47 @@ 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 (IS_ERR(link)) {
+ dev_err(dev, "Failed to add device_link to pcie pd: %ld\n", PTR_ERR(link));
+ return PTR_ERR(link);
+ }
+
+ 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;

switch (imx6_pcie->variant) {
@@ -1013,10 +1057,14 @@ static int imx6_pcie_probe(struct platform_device *pdev)
imx6_pcie->vpcie = NULL;
}

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;

return 0;
--
2.17.1
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