1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Reset driver for the StarFive JH7100 SoC 4 * 5 * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk> 6 */ 7 8 #include <linux/mod_devicetable.h> 9 #include <linux/platform_device.h> 10 11 #include "reset-starfive-jh71x0.h" 12 13 #include <dt-bindings/reset/starfive-jh7100.h> 14 15 /* register offsets */ 16 #define JH7100_RESET_ASSERT0 0x00 17 #define JH7100_RESET_ASSERT1 0x04 18 #define JH7100_RESET_ASSERT2 0x08 19 #define JH7100_RESET_ASSERT3 0x0c 20 #define JH7100_RESET_STATUS0 0x10 21 #define JH7100_RESET_STATUS1 0x14 22 #define JH7100_RESET_STATUS2 0x18 23 #define JH7100_RESET_STATUS3 0x1c 24 25 /* 26 * Writing a 1 to the n'th bit of the m'th ASSERT register asserts 27 * line 32m + n, and writing a 0 deasserts the same line. 28 * Most reset lines have their status inverted so a 0 bit in the STATUS 29 * register means the line is asserted and a 1 means it's deasserted. A few 30 * lines don't though, so store the expected value of the status registers when 31 * all lines are asserted. 32 */ 33 static const u32 jh7100_reset_asserted[4] = { 34 /* STATUS0 */ 35 BIT(JH7100_RST_U74 % 32) | 36 BIT(JH7100_RST_VP6_DRESET % 32) | 37 BIT(JH7100_RST_VP6_BRESET % 32), 38 /* STATUS1 */ 39 BIT(JH7100_RST_HIFI4_DRESET % 32) | 40 BIT(JH7100_RST_HIFI4_BRESET % 32), 41 /* STATUS2 */ 42 BIT(JH7100_RST_E24 % 32), 43 /* STATUS3 */ 44 0, 45 }; 46 47 static int __init jh7100_reset_probe(struct platform_device *pdev) 48 { 49 void __iomem *base = devm_platform_ioremap_resource(pdev, 0); 50 51 if (IS_ERR(base)) 52 return PTR_ERR(base); 53 54 return reset_starfive_jh71x0_register(&pdev->dev, pdev->dev.of_node, 55 base + JH7100_RESET_ASSERT0, 56 base + JH7100_RESET_STATUS0, 57 jh7100_reset_asserted, 58 JH7100_RSTN_END, 59 THIS_MODULE); 60 } 61 62 static const struct of_device_id jh7100_reset_dt_ids[] = { 63 { .compatible = "starfive,jh7100-reset" }, 64 { /* sentinel */ } 65 }; 66 67 static struct platform_driver jh7100_reset_driver = { 68 .driver = { 69 .name = "jh7100-reset", 70 .of_match_table = jh7100_reset_dt_ids, 71 .suppress_bind_attrs = true, 72 }, 73 }; 74 builtin_platform_driver_probe(jh7100_reset_driver, jh7100_reset_probe); 75