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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 | // SPDX-License-Identifier: GPL-2.0-only /* * Voltage regulators coupler for MediaTek SoCs * * Copyright (C) 2022 Collabora, Ltd. * Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/init.h> #include <linux/kernel.h> #include <linux/of.h> #include <linux/regulator/coupler.h> #include <linux/regulator/driver.h> #include <linux/regulator/machine.h> #include <linux/suspend.h> #define to_mediatek_coupler(x) container_of(x, struct mediatek_regulator_coupler, coupler) struct mediatek_regulator_coupler { struct regulator_coupler coupler; struct regulator_dev *vsram_rdev; }; /* * We currently support only couples of not more than two vregs and * modify the vsram voltage only when changing voltage of vgpu. * * This function is limited to the GPU<->SRAM voltages relationships. */ static int mediatek_regulator_balance_voltage(struct regulator_coupler *coupler, struct regulator_dev *rdev, suspend_state_t state) { struct mediatek_regulator_coupler *mrc = to_mediatek_coupler(coupler); int max_spread = rdev->constraints->max_spread[0]; int vsram_min_uV = mrc->vsram_rdev->constraints->min_uV; int vsram_max_uV = mrc->vsram_rdev->constraints->max_uV; int vsram_target_min_uV, vsram_target_max_uV; int min_uV = 0; int max_uV = INT_MAX; int ret; /* * If the target device is on, setting the SRAM voltage directly * is not supported as it scales through its coupled supply voltage. * * An exception is made in case the use_count is zero: this means * that this is the first time we power up the SRAM regulator, which * implies that the target device has yet to perform initialization * and setting a voltage at that time is harmless. */ if (rdev == mrc->vsram_rdev) { if (rdev->use_count == 0) return regulator_do_balance_voltage(rdev, state, true); return -EPERM; } ret = regulator_check_consumers(rdev, &min_uV, &max_uV, state); if (ret < 0) return ret; if (min_uV == 0) { ret = regulator_get_voltage_rdev(rdev); if (ret < 0) return ret; min_uV = ret; } ret = regulator_check_voltage(rdev, &min_uV, &max_uV); if (ret < 0) return ret; /* * If we're asked to set a voltage less than VSRAM min_uV, set * the minimum allowed voltage on VSRAM, as in this case it is * safe to ignore the max_spread parameter. */ vsram_target_min_uV = max(vsram_min_uV, min_uV + max_spread); vsram_target_max_uV = min(vsram_max_uV, vsram_target_min_uV + max_spread); /* Make sure we're not out of range */ vsram_target_min_uV = min(vsram_target_min_uV, vsram_max_uV); pr_debug("Setting voltage %d-%duV on %s (minuV %d)\n", vsram_target_min_uV, vsram_target_max_uV, rdev_get_name(mrc->vsram_rdev), min_uV); ret = regulator_set_voltage_rdev(mrc->vsram_rdev, vsram_target_min_uV, vsram_target_max_uV, state); if (ret) return ret; /* The sram voltage is now balanced: update the target vreg voltage */ return regulator_do_balance_voltage(rdev, state, true); } static int mediatek_regulator_attach(struct regulator_coupler *coupler, struct regulator_dev *rdev) { struct mediatek_regulator_coupler *mrc = to_mediatek_coupler(coupler); const char *rdev_name = rdev_get_name(rdev); /* * If we're getting a coupling of more than two regulators here and * this means that this is surely not a GPU<->SRAM couple: in that * case, we may want to use another coupler implementation, if any, * or the generic one: the regulator core will keep walking through * the list of couplers when any .attach_regulator() cb returns 1. */ if (rdev->coupling_desc.n_coupled > 2) return 1; if (strstr(rdev_name, "sram")) { if (mrc->vsram_rdev) return -EINVAL; mrc->vsram_rdev = rdev; } else if (!strstr(rdev_name, "vgpu") && !strstr(rdev_name, "Vgpu")) { return 1; } return 0; } static int mediatek_regulator_detach(struct regulator_coupler *coupler, struct regulator_dev *rdev) { struct mediatek_regulator_coupler *mrc = to_mediatek_coupler(coupler); if (rdev == mrc->vsram_rdev) mrc->vsram_rdev = NULL; return 0; } static struct mediatek_regulator_coupler mediatek_coupler = { .coupler = { .attach_regulator = mediatek_regulator_attach, .detach_regulator = mediatek_regulator_detach, .balance_voltage = mediatek_regulator_balance_voltage, }, }; static int mediatek_regulator_coupler_init(void) { if (!of_machine_is_compatible("mediatek,mt8183") && !of_machine_is_compatible("mediatek,mt8186") && !of_machine_is_compatible("mediatek,mt8192")) return 0; return regulator_coupler_register(&mediatek_coupler.coupler); } arch_initcall(mediatek_regulator_coupler_init); MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>"); MODULE_DESCRIPTION("MediaTek Regulator Coupler driver"); MODULE_LICENSE("GPL"); |