Enabling runtime power management support on samsung-usb3 phy
and further adding support to turn off the PHY ref_clk PLL.
It thereby requires PHY ref_clk to be switched between internal
core clock and external PLL clock.
Signed-off-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
---
drivers/usb/phy/samsung-usb3.c | 107 +++++++++++++++++++++++++++++++++++--
drivers/usb/phy/samsung-usbphy.c | 26 +++++++++
drivers/usb/phy/samsung-usbphy.h | 1 +
3 files changed, 128 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/phy/samsung-usb3.c b/drivers/usb/phy/samsung-usb3.c
index 29e1321..4dbef15 100644
--- a/drivers/usb/phy/samsung-usb3.c
+++ b/drivers/usb/phy/samsung-usb3.c
@@ -22,8 +22,10 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
+#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/of.h>
+#include <linux/pm_runtime.h>
#include <linux/usb/samsung_usb_phy.h>
#include <linux/platform_data/samsung-usbphy.h>
@@ -32,7 +34,7 @@
/*
* Sets the phy clk as EXTREFCLK (XXTI) which is internal clock from clock core.
*/
-static u32 samsung_usb3_phy_set_refclk(struct samsung_usbphy *sphy)
+static u32 samsung_usb3_phy_set_refclk_int(struct samsung_usbphy *sphy)
{
u32 reg;
u32 refclk;
@@ -65,7 +67,22 @@ static u32 samsung_usb3_phy_set_refclk(struct samsung_usbphy *sphy)
return reg;
}
-static int samsung_exynos5_usb3_phy_enable(struct samsung_usbphy *sphy)
+/*
+ * Sets the phy clk as ref_pad_clk (XusbXTI) which is clock from external PLL.
+ */
+static u32 samsung_usb3_phy_set_refclk_ext(void)
+{
+ u32 reg;
+
+ reg = PHYCLKRST_REFCLKSEL_PAD_REFCLK |
+ PHYCLKRST_FSEL_PAD_100MHZ |
+ PHYCLKRST_MPLL_MULTIPLIER_100MHZ_REF;
+
+ return reg;
+}
+
+static int samsung_exynos5_usb3_phy_enable(struct samsung_usbphy *sphy,
+ bool use_ext_clk)
{
void __iomem *regs = sphy->regs;
u32 phyparam0;
@@ -80,7 +97,11 @@ static int samsung_exynos5_usb3_phy_enable(struct samsung_usbphy *sphy)
phyparam0 = readl(regs + EXYNOS5_DRD_PHYPARAM0);
/* Select PHY CLK source */
- phyparam0 &= ~PHYPARAM0_REF_USE_PAD;
+ if (use_ext_clk)
+ phyparam0 |= PHYPARAM0_REF_USE_PAD;
+ else
+ phyparam0 &= ~PHYPARAM0_REF_USE_PAD;
+
/* Set Loss-of-Signal Detector sensitivity */
phyparam0 &= ~PHYPARAM0_REF_LOSLEVEL_MASK;
phyparam0 |= PHYPARAM0_REF_LOSLEVEL;
@@ -115,7 +136,10 @@ static int samsung_exynos5_usb3_phy_enable(struct samsung_usbphy *sphy)
/* UTMI Power Control */
writel(PHYUTMI_OTGDISABLE, regs + EXYNOS5_DRD_PHYUTMI);
- phyclkrst = samsung_usb3_phy_set_refclk(sphy);
+ if (use_ext_clk)
+ phyclkrst = samsung_usb3_phy_set_refclk_ext();
+ else
+ phyclkrst = samsung_usb3_phy_set_refclk_int(sphy);
phyclkrst |= PHYCLKRST_PORTRESET |
/* Digital power supply in normal operating mode */
@@ -163,7 +187,7 @@ static void samsung_exynos5_usb3_phy_disable(struct samsung_usbphy *sphy)
writel(phytest, regs + EXYNOS5_DRD_PHYTEST);
}
-static int samsung_usb3_phy_init(struct usb_phy *phy)
+static int samsung_exynos5_usb3_phy_init(struct usb_phy *phy, bool use_ext_clk)
{
struct samsung_usbphy *sphy;
unsigned long flags;
@@ -187,7 +211,7 @@ static int samsung_usb3_phy_init(struct usb_phy *phy)
samsung_usbphy_set_isolation(sphy, false);
/* Initialize usb phy registers */
- samsung_exynos5_usb3_phy_enable(sphy);
+ samsung_exynos5_usb3_phy_enable(sphy, use_ext_clk);
spin_unlock_irqrestore(&sphy->lock, flags);
@@ -198,6 +222,34 @@ static int samsung_usb3_phy_init(struct usb_phy *phy)
}
/*
+ * Switch between internal core clock and external oscillator clock
+ * for PHY reference clock
+ */
+static int samsung_exynos5_usb3phy_clk_switch(struct usb_phy *phy,
+ bool use_ext_clk)
+{
+ /*
+ * This will switch PHY refclk from internal core clock
+ * to external PLL clock when device is in use and vice versa
+ * when device plunge into runtime suspend mode.
+ */
+ return samsung_exynos5_usb3_phy_init(phy, use_ext_clk);
+}
+
+/*
+ * The function passed to the usb driver for phy initialization
+ */
+static int samsung_usb3_phy_init(struct usb_phy *phy)
+{
+ /*
+ * We start with using PHY refclk from external PLL,
+ * once runtime suspend for the device is called this
+ * will change to internal core clock
+ */
+ return samsung_exynos5_usb3_phy_init(phy, true);
+}
+
+/*
* The function passed to the usb driver for phy shutdown
*/
static void samsung_usb3_phy_shutdown(struct usb_phy *phy)
@@ -287,6 +339,9 @@ static int samsung_usb3_phy_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, sphy);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
return usb_add_phy(&sphy->phy, USB_PHY_TYPE_USB3);
}
@@ -296,6 +351,8 @@ static int samsung_usb3_phy_remove(struct platform_device *pdev)
usb_remove_phy(&sphy->phy);
+ pm_runtime_disable(&pdev->dev);
+
if (sphy->pmuregs)
iounmap(sphy->pmuregs);
if (sphy->sysreg)
@@ -304,6 +361,42 @@ static int samsung_usb3_phy_remove(struct platform_device *pdev)
return 0;
}
+static int samsung_usb3_phy_runtime_suspend(struct device *dev)
+{
+ struct samsung_usbphy *sphy = dev_get_drvdata(dev);
+
+ samsung_exynos5_usb3phy_clk_switch(&sphy->phy, false);
+
+ if (gpio_is_valid(sphy->phyclk_gpio))
+ gpio_set_value(sphy->phyclk_gpio, 0);
+
+ return 0;
+}
+
+static int samsung_usb3_phy_runtime_resume(struct device *dev)
+{
+ struct samsung_usbphy *sphy = dev_get_drvdata(dev);
+
+ if (gpio_is_valid(sphy->phyclk_gpio)) {
+ gpio_set_value(sphy->phyclk_gpio, 1);
+ /*
+ * PI6C557-03 clock generator needs 3ms typically to stabilise,
+ * but the datasheet doesn't list max. We'll sleep for 10ms
+ * and cross our fingers that it's enough.
+ */
+ usleep_range(10000, 20000);
+ }
+
+ samsung_exynos5_usb3phy_clk_switch(&sphy->phy, true);
+
+ return 0;
+}
+
+static const struct dev_pm_ops samsung_usb3_phy_pm_ops = {
+ SET_RUNTIME_PM_OPS(samsung_usb3_phy_runtime_suspend,
+ samsung_usb3_phy_runtime_resume, NULL)
+};
+
static struct samsung_usbphy_drvdata usb3_phy_exynos5 = {
.cpu_type = TYPE_EXYNOS5250,
.devphy_en_mask = EXYNOS_USBPHY_ENABLE,
@@ -338,7 +431,9 @@ static struct platform_driver samsung_usb3_phy_driver = {
.name = "samsung-usb3-phy",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(samsung_usbphy_dt_match),
+ .pm = &samsung_usb3_phy_pm_ops,
},
+
};
module_platform_driver(samsung_usb3_phy_driver);
diff --git a/drivers/usb/phy/samsung-usbphy.c b/drivers/usb/phy/samsung-usbphy.c
index 7782a43..fb17b84 100644
--- a/drivers/usb/phy/samsung-usbphy.c
+++ b/drivers/usb/phy/samsung-usbphy.c
@@ -26,6 +26,7 @@
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
+#include <linux/of_gpio.h>
#include <linux/usb/samsung_usb_phy.h>
#include "samsung-usbphy.h"
@@ -33,6 +34,7 @@
int samsung_usbphy_parse_dt(struct samsung_usbphy *sphy)
{
struct device_node *usbphy_sys;
+ int ret;
/* Getting node for system controller interface for usb-phy */
usbphy_sys = of_get_child_by_name(sphy->dev->of_node, "usbphy-sys");
@@ -57,6 +59,30 @@ int samsung_usbphy_parse_dt(struct samsung_usbphy *sphy)
if (sphy->sysreg == NULL)
dev_warn(sphy->dev, "Can't get usb-phy sysreg cfg register\n");
+ /* Getting PHY clk gpio here to enable/disable PHY clock PLL, if any */
+ sphy->phyclk_gpio = of_get_named_gpio(sphy->dev->of_node,
+ "samsung,phyclk-gpio", 0);
+ /*
+ * We don't want to return error code here in case we don't get the
+ * PHY clock gpio, some PHYs may not have it.
+ */
+ if (gpio_is_valid(sphy->phyclk_gpio)) {
+ ret = gpio_request_one(sphy->phyclk_gpio, GPIOF_INIT_HIGH,
+ "samsung_usb_phy_clock_en");
+ if (ret) {
+ /*
+ * We don't want to return error code here,
+ * sometimes either of usb2 phy or usb3 phy may not
+ * have the PHY clock gpio.
+ */
+ dev_err(sphy->dev, "can't request phyclk gpio %d\n",
+ sphy->phyclk_gpio);
+ sphy->phyclk_gpio = -EINVAL;
+ }
+ } else {
+ dev_warn(sphy->dev, "Can't get usb-phy clock gpio\n");
+ }
+
of_node_put(usbphy_sys);
return 0;
diff --git a/drivers/usb/phy/samsung-usbphy.h b/drivers/usb/phy/samsung-usbphy.h
index f7e657d..1921ab0 100644
--- a/drivers/usb/phy/samsung-usbphy.h
+++ b/drivers/usb/phy/samsung-usbphy.h
@@ -300,6 +300,7 @@ struct samsung_usbphy {
enum samsung_usb_phy_type phy_type;
atomic_t phy_usage;
spinlock_t lock;
+ int phyclk_gpio;
};
#define phy_to_sphy(x) container_of((x), struct samsung_usbphy, phy)
--
1.7.6.5
--
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