Add initial OPP and SoC core voltage scaling support to the Tegra EHCI driver. This is required for enabling system-wide DVFS on older Tegra SoCs. Tested-by: Peter Geis <pgwipeout@xxxxxxxxx> Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> --- drivers/usb/host/Kconfig | 1 + drivers/usb/host/ehci-tegra.c | 79 +++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig index ab12c4bf0ef1..35c42bc05c5a 100644 --- a/drivers/usb/host/Kconfig +++ b/drivers/usb/host/Kconfig @@ -278,6 +278,7 @@ config USB_EHCI_TEGRA depends on ARCH_TEGRA select USB_EHCI_ROOT_HUB_TT select USB_TEGRA_PHY + select PM_OPP help This driver enables support for the internal USB Host Controllers found in NVIDIA Tegra SoCs. The controllers are EHCI compliant. diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index 869d9c4de5fc..0976577f54b4 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -17,6 +17,7 @@ #include <linux/of_device.h> #include <linux/of_gpio.h> #include <linux/platform_device.h> +#include <linux/pm_opp.h> #include <linux/pm_runtime.h> #include <linux/reset.h> #include <linux/slab.h> @@ -364,6 +365,79 @@ static void tegra_ehci_unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb) free_dma_aligned_buffer(urb); } +static void tegra_ehci_deinit_opp_table(void *data) +{ + struct device *dev = data; + struct opp_table *opp_table; + + opp_table = dev_pm_opp_get_opp_table(dev); + dev_pm_opp_of_remove_table(dev); + dev_pm_opp_put_regulators(opp_table); + dev_pm_opp_put_opp_table(opp_table); +} + +static int devm_tegra_ehci_init_opp_table(struct device *dev) +{ + unsigned long rate = ULONG_MAX; + struct opp_table *opp_table; + const char *rname = "core"; + struct dev_pm_opp *opp; + int err; + + /* legacy device-trees don't have OPP table */ + if (!device_property_present(dev, "operating-points-v2")) + return 0; + + /* voltage scaling is optional */ + if (device_property_present(dev, "core-supply")) + opp_table = dev_pm_opp_set_regulators(dev, &rname, 1); + else + opp_table = dev_pm_opp_get_opp_table(dev); + + if (IS_ERR(opp_table)) + return dev_err_probe(dev, PTR_ERR(opp_table), + "failed to prepare OPP table\n"); + + err = dev_pm_opp_of_add_table(dev); + if (err) { + dev_err(dev, "failed to add OPP table: %d\n", err); + goto put_table; + } + + /* find suitable OPP for the maximum clock rate */ + opp = dev_pm_opp_find_freq_floor(dev, &rate); + err = PTR_ERR_OR_ZERO(opp); + if (err) { + dev_err(dev, "failed to get OPP: %d\n", err); + goto remove_table; + } + + dev_pm_opp_put(opp); + + /* + * First dummy rate-set initializes voltage vote by setting voltage + * in accordance to the clock rate. + */ + err = dev_pm_opp_set_rate(dev, rate); + if (err) { + dev_err(dev, "failed to initialize OPP clock: %d\n", err); + goto remove_table; + } + + err = devm_add_action(dev, tegra_ehci_deinit_opp_table, dev); + if (err) + goto remove_table; + + return 0; + +remove_table: + dev_pm_opp_of_remove_table(dev); +put_table: + dev_pm_opp_put_regulators(opp_table); + + return err; +} + static const struct tegra_ehci_soc_config tegra30_soc_config = { .has_hostpc = true, }; @@ -431,6 +505,11 @@ static int tegra_ehci_probe(struct platform_device *pdev) goto cleanup_hcd_create; } + err = devm_tegra_ehci_init_opp_table(&pdev->dev); + if (err) + return dev_err_probe(&pdev->dev, err, + "Failed to initialize OPP\n"); + err = clk_prepare_enable(tegra->clk); if (err) goto cleanup_hcd_create; -- 2.27.0 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel