Add custom voltage regulator coupler for Exynos5800 SoCs, which require coupling between "vdd_arm" and "vdd_int" regulators. This coupler ensures that coupled regulators voltage balancing is done only when clients for each regulator (cpufreq for "vdd_arm" and devfreq for "vdd_int") apply their constraints, so the voltage values don't go beyond the bootloader-selected operation point during the boot process. This also ensures proper voltage balancing if any of those drivers is missing. Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> --- arch/arm/mach-exynos/Kconfig | 1 + drivers/soc/samsung/Kconfig | 3 + drivers/soc/samsung/Makefile | 1 + .../soc/samsung/exynos-regulator-coupler.c | 59 +++++++++++++++++++ 4 files changed, 64 insertions(+) create mode 100644 drivers/soc/samsung/exynos-regulator-coupler.c diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig index 76838255b5fa..f185cd3d4c62 100644 --- a/arch/arm/mach-exynos/Kconfig +++ b/arch/arm/mach-exynos/Kconfig @@ -118,6 +118,7 @@ config SOC_EXYNOS5800 bool "Samsung EXYNOS5800" default y depends on SOC_EXYNOS5420 + select EXYNOS_REGULATOR_COUPLER config EXYNOS_MCPM bool diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig index c7a2003687c7..264185664594 100644 --- a/drivers/soc/samsung/Kconfig +++ b/drivers/soc/samsung/Kconfig @@ -37,4 +37,7 @@ config EXYNOS_PM_DOMAINS bool "Exynos PM domains" if COMPILE_TEST depends on PM_GENERIC_DOMAINS || COMPILE_TEST +config EXYNOS_REGULATOR_COUPLER + bool "Exynos SoC Regulator Coupler" if COMPILE_TEST + depends on ARCH_EXYNOS || COMPILE_TEST endif diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile index edd1d6ea064d..ecc3a32f6406 100644 --- a/drivers/soc/samsung/Makefile +++ b/drivers/soc/samsung/Makefile @@ -9,3 +9,4 @@ obj-$(CONFIG_EXYNOS_PMU) += exynos-pmu.o obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS) += exynos3250-pmu.o exynos4-pmu.o \ exynos5250-pmu.o exynos5420-pmu.o obj-$(CONFIG_EXYNOS_PM_DOMAINS) += pm_domains.o +obj-$(CONFIG_EXYNOS_REGULATOR_COUPLER) += exynos-regulator-coupler.o diff --git a/drivers/soc/samsung/exynos-regulator-coupler.c b/drivers/soc/samsung/exynos-regulator-coupler.c new file mode 100644 index 000000000000..54445918bd75 --- /dev/null +++ b/drivers/soc/samsung/exynos-regulator-coupler.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2020 Samsung Electronics Co., Ltd. + * http://www.samsung.com/ + * Author: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> + * + * Samsung Exynos SoC voltage coupler + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/regulator/coupler.h> +#include <linux/regulator/driver.h> + +static int exynos_coupler_balance_voltage(struct regulator_coupler *coupler, + struct regulator_dev *rdev, + suspend_state_t state) +{ + struct coupling_desc *c_desc = &rdev->coupling_desc; + int ret, cons_uV = 0, cons_max_uV = INT_MAX; + bool skip_coupled = false; + + /* get coupled regulator constraints */ + ret = regulator_check_consumers(c_desc->coupled_rdevs[1], &cons_uV, + &cons_max_uV, state); + if (ret < 0) + return ret; + + /* skip adjusting coupled regulator if it has no constraints set yet */ + if (cons_uV == 0) + skip_coupled = true; + + return regulator_do_balance_voltage(rdev, state, skip_coupled); +} + +static int exynos_coupler_attach(struct regulator_coupler *coupler, + struct regulator_dev *rdev) +{ + if (strcmp(rdev_get_name(rdev), "vdd_arm") == 0 || + strcmp(rdev_get_name(rdev), "vdd_int") == 0) + return 0; + + return -EINVAL; +} + +static struct regulator_coupler exynos_coupler = { + .attach_regulator = exynos_coupler_attach, + .balance_voltage = exynos_coupler_balance_voltage, +}; + +static int __init exynos_coupler_init(void) +{ + if (!of_machine_is_compatible("samsung,exynos5800")) + return 0; + + return regulator_coupler_register(&exynos_coupler); +} +arch_initcall(exynos_coupler_init); -- 2.17.1
