1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Apple SoC SPMI device driver 4 * 5 * Copyright The Asahi Linux Contributors 6 * 7 * Inspired by: 8 * OpenBSD support Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org> 9 * Correllium support Copyright (C) 2021 Corellium LLC 10 * hisi-spmi-controller.c 11 * spmi-pmic-arb.c Copyright (c) 2021, The Linux Foundation. 12 */ 13 14 #include <linux/io.h> 15 #include <linux/iopoll.h> 16 #include <linux/module.h> 17 #include <linux/platform_device.h> 18 #include <linux/spmi.h> 19 20 /* SPMI Controller Registers */ 21 #define SPMI_STATUS_REG 0 22 #define SPMI_CMD_REG 0x4 23 #define SPMI_RSP_REG 0x8 24 25 #define SPMI_RX_FIFO_EMPTY BIT(24) 26 27 #define REG_POLL_INTERVAL_US 10000 28 #define REG_POLL_TIMEOUT_US (REG_POLL_INTERVAL_US * 5) 29 30 struct apple_spmi { 31 void __iomem *regs; 32 }; 33 34 #define poll_reg(spmi, reg, val, cond) \ 35 readl_poll_timeout((spmi)->regs + (reg), (val), (cond), \ 36 REG_POLL_INTERVAL_US, REG_POLL_TIMEOUT_US) 37 38 static inline u32 apple_spmi_pack_cmd(u8 opc, u8 sid, u16 saddr, size_t len) 39 { 40 return opc | sid << 8 | saddr << 16 | (len - 1) | (1 << 15); 41 } 42 43 /* Wait for Rx FIFO to have something */ 44 static int apple_spmi_wait_rx_not_empty(struct spmi_controller *ctrl) 45 { 46 struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl); 47 int ret; 48 u32 status; 49 50 ret = poll_reg(spmi, SPMI_STATUS_REG, status, !(status & SPMI_RX_FIFO_EMPTY)); 51 if (ret) { 52 dev_err(&ctrl->dev, 53 "failed to wait for RX FIFO not empty\n"); 54 return ret; 55 } 56 57 return 0; 58 } 59 60 static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid, 61 u16 saddr, u8 *buf, size_t len) 62 { 63 struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl); 64 u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len); 65 u32 rsp; 66 size_t len_read = 0; 67 u8 i; 68 int ret; 69 70 writel(spmi_cmd, spmi->regs + SPMI_CMD_REG); 71 72 ret = apple_spmi_wait_rx_not_empty(ctrl); 73 if (ret) 74 return ret; 75 76 /* Discard SPMI reply status */ 77 readl(spmi->regs + SPMI_RSP_REG); 78 79 /* Read SPMI data reply */ 80 while (len_read < len) { 81 rsp = readl(spmi->regs + SPMI_RSP_REG); 82 i = 0; 83 while ((len_read < len) && (i < 4)) { 84 buf[len_read++] = ((0xff << (8 * i)) & rsp) >> (8 * i); 85 i += 1; 86 } 87 } 88 89 return 0; 90 } 91 92 static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid, 93 u16 saddr, const u8 *buf, size_t len) 94 { 95 struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl); 96 u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len); 97 size_t i = 0, j; 98 int ret; 99 100 writel(spmi_cmd, spmi->regs + SPMI_CMD_REG); 101 102 while (i < len) { 103 j = 0; 104 spmi_cmd = 0; 105 while ((j < 4) & (i < len)) 106 spmi_cmd |= buf[i++] << (j++ * 8); 107 108 writel(spmi_cmd, spmi->regs + SPMI_CMD_REG); 109 } 110 111 ret = apple_spmi_wait_rx_not_empty(ctrl); 112 if (ret) 113 return ret; 114 115 /* Discard */ 116 readl(spmi->regs + SPMI_RSP_REG); 117 118 return 0; 119 } 120 121 static int apple_spmi_probe(struct platform_device *pdev) 122 { 123 struct apple_spmi *spmi; 124 struct spmi_controller *ctrl; 125 int ret; 126 127 ctrl = devm_spmi_controller_alloc(&pdev->dev, sizeof(*spmi)); 128 if (IS_ERR(ctrl)) 129 return -ENOMEM; 130 131 spmi = spmi_controller_get_drvdata(ctrl); 132 133 spmi->regs = devm_platform_ioremap_resource(pdev, 0); 134 if (IS_ERR(spmi->regs)) 135 return PTR_ERR(spmi->regs); 136 137 ctrl->dev.of_node = pdev->dev.of_node; 138 139 ctrl->read_cmd = spmi_read_cmd; 140 ctrl->write_cmd = spmi_write_cmd; 141 142 ret = devm_spmi_controller_add(&pdev->dev, ctrl); 143 if (ret) 144 return dev_err_probe(&pdev->dev, ret, 145 "spmi_controller_add failed\n"); 146 147 return 0; 148 } 149 150 static const struct of_device_id apple_spmi_match_table[] = { 151 { .compatible = "apple,t8103-spmi", }, 152 { .compatible = "apple,spmi", }, 153 {} 154 }; 155 MODULE_DEVICE_TABLE(of, apple_spmi_match_table); 156 157 static struct platform_driver apple_spmi_driver = { 158 .probe = apple_spmi_probe, 159 .driver = { 160 .name = "apple-spmi", 161 .of_match_table = apple_spmi_match_table, 162 }, 163 }; 164 module_platform_driver(apple_spmi_driver); 165 166 MODULE_AUTHOR("Jean-Francois Bortolotti <jeff@borto.fr>"); 167 MODULE_DESCRIPTION("Apple SoC SPMI driver"); 168 MODULE_LICENSE("GPL"); 169