diff options
Diffstat (limited to 'src/mainboard/google/gru/pwm_regulator.c')
| -rw-r--r-- | src/mainboard/google/gru/pwm_regulator.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/src/mainboard/google/gru/pwm_regulator.c b/src/mainboard/google/gru/pwm_regulator.c new file mode 100644 index 0000000000..f382b2b58c --- /dev/null +++ b/src/mainboard/google/gru/pwm_regulator.c @@ -0,0 +1,82 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2016 Rockchip Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <arch/io.h> +#include <assert.h> +#include <boardid.h> +#include <console/console.h> +#include <soc/grf.h> +#include <soc/pwm.h> + +#include "pwm_regulator.h" + +/* + * Apparently a period of 3333 is determined by EEs to be ideal for our + * board design / resistors / capacitors / regulators but due to + * clock dividers we actually get 3337. + */ +#define PWM_PERIOD 3337 +#define PWM_DESIGN_VOLTAGE_MIN 8000 +#define PWM_DESIGN_VOLTAGE_MAX 15000 + +/* The min & max design voltages are different after kevin-r6 */ +int kevin_voltage_min_max_r6[][2] = { + [PWM_REGULATOR_GPU] = {7910, 12139}, + [PWM_REGULATOR_BIG] = {7986, 13057}, + [PWM_REGULATOR_LIT] = {7997, 13002}, + [PWM_REGULATOR_CENTERLOG] = {7996, 10507} +}; + +void pwm_regulator_configure(enum pwm_regulator pwm, int millivolt) +{ + int duty_ns, voltage_max, voltage_min; + int voltage = millivolt * 10; /* for higer calculation accuracy */ + + switch (pwm) { + case PWM_REGULATOR_GPU: + write32(&rk3399_grf->iomux_pwm_0, IOMUX_PWM_0); + break; + case PWM_REGULATOR_BIG: + write32(&rk3399_grf->iomux_pwm_1, IOMUX_PWM_1); + break; + case PWM_REGULATOR_LIT: + write32(&rk3399_pmugrf->iomux_pwm_2, IOMUX_PWM_2); + break; + case PWM_REGULATOR_CENTERLOG: + write32(&rk3399_pmugrf->iomux_pwm_3a, IOMUX_PWM_3_A); + break; + } + + voltage_min = PWM_DESIGN_VOLTAGE_MIN; + voltage_max = PWM_DESIGN_VOLTAGE_MAX; + if (IS_ENABLED(CONFIG_BOARD_GOOGLE_KEVIN) && board_id() >= 6) { + voltage_min = kevin_voltage_min_max_r6[pwm][0]; + voltage_max = kevin_voltage_min_max_r6[pwm][1]; + } + + assert(voltage <= voltage_max && voltage >= voltage_min); + + /* + * Intentionally round down (higher volt) to be safe. + * eg, for the default min & max design voltage: + * period = 3337, volt = 1.1: 1906 + * period = 3337, volt = 1.0: 2383 + * period = 3337, volt = 0.9: 2860 + */ + duty_ns = PWM_PERIOD * (voltage_max - voltage) + / (voltage_max - voltage_min); + + pwm_init(pwm, PWM_PERIOD, duty_ns); +} |