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