From: Andrew Bresticker <[email protected]> Allow for a warm reset GPIO to be passed to the PMC driver via DT which will be used to reset the system instead of writing to PMC_CTRL. The GPIO will be asserted at reset time and, if this fails to reset the system, we'll fall back to using PMC_CTRL.
Signed-off-by: Andrew Bresticker <[email protected]> [[email protected]: Rebased] Signed-off-by: Tomeu Vizoso <[email protected]> --- .../bindings/arm/tegra/nvidia,tegra20-pmc.txt | 1 + drivers/soc/tegra/pmc.c | 33 ++++++++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-pmc.txt b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-pmc.txt index 02c2700..ee5568f 100644 --- a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-pmc.txt +++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-pmc.txt @@ -34,6 +34,7 @@ Optional properties: - nvidia,combined-power-req : Boolean, combined power request for CPU & Core - nvidia,cpu-pwr-good-en : Boolean, CPU power good signal (from PMIC to PMC) is enabled. +- nvidia,reset-gpio : GPIO that can be used to warm reset the system. Required properties when nvidia,suspend-mode is specified: - nvidia,cpu-pwr-good-time : CPU power good time in uS. diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c index c956395..effed0c 100644 --- a/drivers/soc/tegra/pmc.c +++ b/drivers/soc/tegra/pmc.c @@ -24,10 +24,12 @@ #include <linux/delay.h> #include <linux/err.h> #include <linux/export.h> +#include <linux/gpio.h> #include <linux/init.h> #include <linux/io.h> #include <linux/of.h> #include <linux/of_address.h> +#include <linux/of_gpio.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/reset.h> @@ -127,6 +129,8 @@ struct tegra_pmc_soc { * @lp0_vec_phys: physical base address of the LP0 warm boot code * @lp0_vec_size: size of the LP0 warm boot code * @powergates_lock: mutex for power gate register access + * @reset_gpio: GPIO to assert to reset the system + * @reset_active_low: Reset GPIO is active-low */ struct tegra_pmc { struct device *dev; @@ -149,6 +153,9 @@ struct tegra_pmc { bool cpu_pwr_good_en; u32 lp0_vec_phys; u32 lp0_vec_size; + int reset_gpio; + bool reset_active_low; + struct mutex powergates_lock; }; @@ -386,6 +393,17 @@ void tegra_pmc_restart(enum reboot_mode mode, const char *cmd) { u32 value; + /* + * If there's a reset GPIO, attempt to use that first and then fall + * back to PMC reset if that fails. + */ + if (gpio_is_valid(pmc->reset_gpio)) { + value = pmc->reset_active_low ? 0 : 1; + gpio_direction_output(pmc->reset_gpio, value); + udelay(100); + pr_err("GPIO reset failed; using PMC reset...\n"); + } + value = tegra_pmc_readl(PMC_SCRATCH0); value &= ~PMC_SCRATCH0_MODE_MASK; @@ -629,6 +647,8 @@ void tegra_pmc_enter_suspend_mode(enum tegra_suspend_mode mode) static int tegra_pmc_parse_dt(struct tegra_pmc *pmc, struct device_node *np) { u32 value, values[2]; + enum of_gpio_flags flags; + int err; if (of_property_read_u32(np, "nvidia,suspend-mode", &value)) { } else { @@ -695,6 +715,19 @@ static int tegra_pmc_parse_dt(struct tegra_pmc *pmc, struct device_node *np) pmc->lp0_vec_phys = values[0]; pmc->lp0_vec_size = values[1]; + pmc->reset_gpio = of_get_named_gpio_flags(np, "nvidia,reset-gpio", + 0, &flags); + if (gpio_is_valid(pmc->reset_gpio)) { + err = gpio_request_one(pmc->reset_gpio, GPIOF_OUT_INIT_HIGH, + "soc-warm-reset"); + if (err) { + pr_err("Failed to request reset GPIO: %d\n", err); + pmc->reset_gpio = -1; + } + if (flags & OF_GPIO_ACTIVE_LOW) + pmc->reset_active_low = true; + } + return 0; } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
