Add a simple custom voltage regulator coupler for Exynos5800 SoCs, which require coupling between "vdd_arm" and "vdd_int" regulators. This coupler ensures that the voltage balancing for the coupled regulators is done only when clients for the each regulator 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 the client driver is missing. Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> --- v2: - removed dependency on the regulator names as pointed by krzk, now it works with all coupled regulators. So far the coupling between the regulators on Exynos5800 based boards is defined only between "vdd_arm" and "vdd_int" supplies. --- arch/arm/mach-exynos/Kconfig | 1 + drivers/soc/samsung/Kconfig | 3 + drivers/soc/samsung/Makefile | 1 + .../soc/samsung/exynos-regulator-coupler.c | 56 +++++++++++++++++++ 4 files changed, 61 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..370a0ce4de3a --- /dev/null +++ b/drivers/soc/samsung/exynos-regulator-coupler.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2020 Samsung Electronics Co., Ltd. + * http://www.samsung.com/ + * Author: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> + * + * Simple Samsung Exynos SoC voltage coupler. Ensures that all + * clients set their constraints before balancing the voltages. + */ + +#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) +{ + return 0; +} + +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
