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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | +/* |
| 3 | + * Copyright (c) 2023 Code Construct |
| 4 | + * |
| 5 | + * Author: Jeremy Kerr <jk@codeconstruct.com.au> |
| 6 | + */ |
| 7 | + |
| 8 | +#include <linux/mfd/syscon.h> |
| 9 | +#include <linux/module.h> |
| 10 | +#include <linux/of.h> |
| 11 | +#include <linux/of_device.h> |
| 12 | +#include <linux/platform_device.h> |
| 13 | +#include <linux/regmap.h> |
| 14 | + |
| 15 | +#include "dw-i3c-master.h" |
| 16 | + |
| 17 | +/* AST2600-specific global register set */ |
| 18 | +#define AST2600_I3CG_REG0(idx) (((idx) * 4 * 4) + 0x10) |
| 19 | +#define AST2600_I3CG_REG1(idx) (((idx) * 4 * 4) + 0x14) |
| 20 | + |
| 21 | +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_MASK GENMASK(29, 28) |
| 22 | +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_2K (0x0 << 28) |
| 23 | +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_750 (0x2 << 28) |
| 24 | +#define AST2600_I3CG_REG0_SDA_PULLUP_EN_545 (0x3 << 28) |
| 25 | + |
| 26 | +#define AST2600_I3CG_REG1_I2C_MODE BIT(0) |
| 27 | +#define AST2600_I3CG_REG1_TEST_MODE BIT(1) |
| 28 | +#define AST2600_I3CG_REG1_ACT_MODE_MASK GENMASK(3, 2) |
| 29 | +#define AST2600_I3CG_REG1_ACT_MODE(x) (((x) << 2) & AST2600_I3CG_REG1_ACT_MODE_MASK) |
| 30 | +#define AST2600_I3CG_REG1_PENDING_INT_MASK GENMASK(7, 4) |
| 31 | +#define AST2600_I3CG_REG1_PENDING_INT(x) (((x) << 4) & AST2600_I3CG_REG1_PENDING_INT_MASK) |
| 32 | +#define AST2600_I3CG_REG1_SA_MASK GENMASK(14, 8) |
| 33 | +#define AST2600_I3CG_REG1_SA(x) (((x) << 8) & AST2600_I3CG_REG1_SA_MASK) |
| 34 | +#define AST2600_I3CG_REG1_SA_EN BIT(15) |
| 35 | +#define AST2600_I3CG_REG1_INST_ID_MASK GENMASK(19, 16) |
| 36 | +#define AST2600_I3CG_REG1_INST_ID(x) (((x) << 16) & AST2600_I3CG_REG1_INST_ID_MASK) |
| 37 | + |
| 38 | +#define AST2600_DEFAULT_SDA_PULLUP_OHMS 2000 |
| 39 | + |
| 40 | +#define DEV_ADDR_TABLE_IBI_PEC BIT(11) |
| 41 | + |
| 42 | +struct ast2600_i3c { |
| 43 | + struct dw_i3c_master dw; |
| 44 | + struct regmap *global_regs; |
| 45 | + unsigned int global_idx; |
| 46 | + unsigned int sda_pullup; |
| 47 | +}; |
| 48 | + |
| 49 | +static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw) |
| 50 | +{ |
| 51 | + return container_of(dw, struct ast2600_i3c, dw); |
| 52 | +} |
| 53 | + |
| 54 | +static int ast2600_i3c_pullup_to_reg(unsigned int ohms, u32 *regp) |
| 55 | +{ |
| 56 | + u32 reg; |
| 57 | + |
| 58 | + switch (ohms) { |
| 59 | + case 2000: |
| 60 | + reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_2K; |
| 61 | + break; |
| 62 | + case 750: |
| 63 | + reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_750; |
| 64 | + break; |
| 65 | + case 545: |
| 66 | + reg = AST2600_I3CG_REG0_SDA_PULLUP_EN_545; |
| 67 | + break; |
| 68 | + default: |
| 69 | + return -EINVAL; |
| 70 | + } |
| 71 | + |
| 72 | + if (regp) |
| 73 | + *regp = reg; |
| 74 | + |
| 75 | + return 0; |
| 76 | +} |
| 77 | + |
| 78 | +static int ast2600_i3c_init(struct dw_i3c_master *dw) |
| 79 | +{ |
| 80 | + struct ast2600_i3c *i3c = to_ast2600_i3c(dw); |
| 81 | + u32 reg = 0; |
| 82 | + int rc; |
| 83 | + |
| 84 | + /* reg0: set SDA pullup values */ |
| 85 | + rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, ®); |
| 86 | + if (rc) |
| 87 | + return rc; |
| 88 | + |
| 89 | + rc = regmap_write(i3c->global_regs, |
| 90 | + AST2600_I3CG_REG0(i3c->global_idx), reg); |
| 91 | + if (rc) |
| 92 | + return rc; |
| 93 | + |
| 94 | + /* reg1: set up the instance id, but leave everything else disabled, |
| 95 | + * as it's all for client mode |
| 96 | + */ |
| 97 | + reg = AST2600_I3CG_REG1_INST_ID(i3c->global_idx); |
| 98 | + rc = regmap_write(i3c->global_regs, |
| 99 | + AST2600_I3CG_REG1(i3c->global_idx), reg); |
| 100 | + |
| 101 | + return rc; |
| 102 | +} |
| 103 | + |
| 104 | +static void ast2600_i3c_set_dat_ibi(struct dw_i3c_master *i3c, |
| 105 | + struct i3c_dev_desc *dev, |
| 106 | + bool enable, u32 *dat) |
| 107 | +{ |
| 108 | + /* |
| 109 | + * The ast2600 i3c controller will lock up on receiving 4n+1-byte IBIs |
| 110 | + * if the PEC is disabled. We have no way to restrict the length of |
| 111 | + * IBIs sent to the controller, so we need to unconditionally enable |
| 112 | + * PEC checking, which means we drop a byte of payload data |
| 113 | + */ |
| 114 | + if (enable && dev->info.bcr & I3C_BCR_IBI_PAYLOAD) { |
| 115 | + dev_warn_once(&i3c->base.dev, |
| 116 | + "Enabling PEC workaround. IBI payloads will be truncated\n"); |
| 117 | + *dat |= DEV_ADDR_TABLE_IBI_PEC; |
| 118 | + } |
| 119 | +} |
| 120 | + |
| 121 | +static const struct dw_i3c_platform_ops ast2600_i3c_ops = { |
| 122 | + .init = ast2600_i3c_init, |
| 123 | + .set_dat_ibi = ast2600_i3c_set_dat_ibi, |
| 124 | +}; |
| 125 | + |
| 126 | +static int ast2600_i3c_probe(struct platform_device *pdev) |
| 127 | +{ |
| 128 | + struct device_node *np = pdev->dev.of_node; |
| 129 | + struct of_phandle_args gspec; |
| 130 | + struct ast2600_i3c *i3c; |
| 131 | + int rc; |
| 132 | + |
| 133 | + i3c = devm_kzalloc(&pdev->dev, sizeof(*i3c), GFP_KERNEL); |
| 134 | + if (!i3c) |
| 135 | + return -ENOMEM; |
| 136 | + |
| 137 | + rc = of_parse_phandle_with_fixed_args(np, "aspeed,global-regs", 1, 0, |
| 138 | + &gspec); |
| 139 | + if (rc) |
| 140 | + return -ENODEV; |
| 141 | + |
| 142 | + i3c->global_regs = syscon_node_to_regmap(gspec.np); |
| 143 | + of_node_put(gspec.np); |
| 144 | + |
| 145 | + if (IS_ERR(i3c->global_regs)) |
| 146 | + return PTR_ERR(i3c->global_regs); |
| 147 | + |
| 148 | + i3c->global_idx = gspec.args[0]; |
| 149 | + |
| 150 | + rc = of_property_read_u32(np, "sda-pullup-ohms", &i3c->sda_pullup); |
| 151 | + if (rc) |
| 152 | + i3c->sda_pullup = AST2600_DEFAULT_SDA_PULLUP_OHMS; |
| 153 | + |
| 154 | + rc = ast2600_i3c_pullup_to_reg(i3c->sda_pullup, NULL); |
| 155 | + if (rc) |
| 156 | + dev_err(&pdev->dev, "invalid sda-pullup value %d\n", |
| 157 | + i3c->sda_pullup); |
| 158 | + |
| 159 | + i3c->dw.platform_ops = &ast2600_i3c_ops; |
| 160 | + i3c->dw.ibi_capable = true; |
| 161 | + return dw_i3c_common_probe(&i3c->dw, pdev); |
| 162 | +} |
| 163 | + |
| 164 | +static void ast2600_i3c_remove(struct platform_device *pdev) |
| 165 | +{ |
| 166 | + struct dw_i3c_master *dw_i3c = platform_get_drvdata(pdev); |
| 167 | + |
| 168 | + dw_i3c_common_remove(dw_i3c); |
| 169 | +} |
| 170 | + |
| 171 | +static const struct of_device_id ast2600_i3c_master_of_match[] = { |
| 172 | + { .compatible = "aspeed,ast2600-i3c", }, |
| 173 | + {}, |
| 174 | +}; |
| 175 | +MODULE_DEVICE_TABLE(of, ast2600_i3c_master_of_match); |
| 176 | + |
| 177 | +static struct platform_driver ast2600_i3c_driver = { |
| 178 | + .probe = ast2600_i3c_probe, |
| 179 | + .remove_new = ast2600_i3c_remove, |
| 180 | + .driver = { |
| 181 | + .name = "ast2600-i3c-master", |
| 182 | + .of_match_table = ast2600_i3c_master_of_match, |
| 183 | + }, |
| 184 | +}; |
| 185 | +module_platform_driver(ast2600_i3c_driver); |
| 186 | + |
| 187 | +MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>"); |
| 188 | +MODULE_DESCRIPTION("ASPEED AST2600 I3C driver"); |
| 189 | +MODULE_LICENSE("GPL"); |
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