| 1 | // SPDX-License-Identifier: GPL-2.0 |
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| 2 | /* |
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| 3 | * Nuvoton WPCM450 SoC Identification |
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| 4 | * |
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| 5 | * Copyright (C) 2022 Jonathan Neuschäfer |
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| 6 | */ |
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| 7 | |
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| 8 | #include <linux/mfd/syscon.h> |
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| 9 | #include <linux/of.h> |
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| 10 | #include <linux/regmap.h> |
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| 11 | #include <linux/slab.h> |
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| 12 | #include <linux/sys_soc.h> |
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| 13 | |
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| 14 | #define GCR_PDID 0 |
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| 15 | #define PDID_CHIP(x) ((x) & 0x00ffffff) |
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| 16 | #define CHIP_WPCM450 0x926450 |
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| 17 | #define PDID_REV(x) ((x) >> 24) |
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| 18 | |
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| 19 | struct revision { |
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| 20 | u8 number; |
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| 21 | const char *name; |
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| 22 | }; |
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| 23 | |
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| 24 | static const struct revision revisions[] __initconst = { |
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| 25 | { 0x00, "Z1" }, |
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| 26 | { 0x03, "Z2" }, |
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| 27 | { 0x04, "Z21" }, |
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| 28 | { 0x08, "A1" }, |
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| 29 | { 0x09, "A2" }, |
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| 30 | { 0x0a, "A3" }, |
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| 31 | {} |
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| 32 | }; |
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| 33 | |
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| 34 | static const char * __init get_revision(unsigned int rev) |
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| 35 | { |
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| 36 | int i; |
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| 37 | |
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| 38 | for (i = 0; revisions[i].name; i++) |
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| 39 | if (revisions[i].number == rev) |
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| 40 | return revisions[i].name; |
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| 41 | return NULL; |
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| 42 | } |
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| 43 | |
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| 44 | static struct soc_device_attribute *wpcm450_attr; |
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| 45 | static struct soc_device *wpcm450_soc; |
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| 46 | |
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| 47 | static int __init wpcm450_soc_init(void) |
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| 48 | { |
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| 49 | struct soc_device_attribute *attr; |
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| 50 | struct soc_device *soc; |
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| 51 | const char *revision; |
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| 52 | struct regmap *gcr; |
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| 53 | u32 pdid; |
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| 54 | int ret; |
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| 55 | |
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| 56 | if (!of_machine_is_compatible(compat: "nuvoton,wpcm450" )) |
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| 57 | return 0; |
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| 58 | |
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| 59 | gcr = syscon_regmap_lookup_by_compatible(s: "nuvoton,wpcm450-gcr" ); |
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| 60 | if (IS_ERR(ptr: gcr)) |
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| 61 | return PTR_ERR(ptr: gcr); |
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| 62 | ret = regmap_read(map: gcr, GCR_PDID, val: &pdid); |
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| 63 | if (ret) |
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| 64 | return ret; |
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| 65 | |
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| 66 | if (PDID_CHIP(pdid) != CHIP_WPCM450) { |
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| 67 | pr_warn("Unknown chip ID in GCR.PDID: 0x%06x\n" , PDID_CHIP(pdid)); |
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| 68 | return -ENODEV; |
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| 69 | } |
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| 70 | |
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| 71 | revision = get_revision(PDID_REV(pdid)); |
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| 72 | if (!revision) { |
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| 73 | pr_warn("Unknown chip revision in GCR.PDID: 0x%02x\n" , PDID_REV(pdid)); |
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| 74 | return -ENODEV; |
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| 75 | } |
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| 76 | |
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| 77 | attr = kzalloc(size: sizeof(*attr), GFP_KERNEL); |
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| 78 | if (!attr) |
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| 79 | return -ENOMEM; |
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| 80 | |
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| 81 | attr->family = "Nuvoton NPCM" ; |
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| 82 | attr->soc_id = "WPCM450" ; |
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| 83 | attr->revision = revision; |
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| 84 | soc = soc_device_register(soc_plat_dev_attr: attr); |
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| 85 | if (IS_ERR(ptr: soc)) { |
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| 86 | kfree(objp: attr); |
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| 87 | pr_warn("Could not register SoC device\n" ); |
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| 88 | return PTR_ERR(ptr: soc); |
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| 89 | } |
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| 90 | |
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| 91 | wpcm450_soc = soc; |
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| 92 | wpcm450_attr = attr; |
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| 93 | return 0; |
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| 94 | } |
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| 95 | module_init(wpcm450_soc_init); |
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| 96 | |
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| 97 | static void __exit wpcm450_soc_exit(void) |
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| 98 | { |
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| 99 | if (wpcm450_soc) { |
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| 100 | soc_device_unregister(soc_dev: wpcm450_soc); |
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| 101 | wpcm450_soc = NULL; |
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| 102 | kfree(objp: wpcm450_attr); |
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| 103 | } |
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| 104 | } |
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| 105 | module_exit(wpcm450_soc_exit); |
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| 106 | |
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| 107 | MODULE_LICENSE("GPL" ); |
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| 108 | MODULE_AUTHOR("Jonathan Neuschäfer" ); |
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| 109 | MODULE_DESCRIPTION("Nuvoton WPCM450 SoC Identification driver" ); |
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| 110 | |
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