tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
42struct 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
49static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw)
50{
51 return container_of(dw, struct ast2600_i3c, dw);
52}
53
54static 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
78static 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
104static 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
121static 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
126static 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
164static 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
171static const struct of_device_id ast2600_i3c_master_of_match[] = {
172 { .compatible = "aspeed,ast2600-i3c", },
173 {},
174};
175MODULE_DEVICE_TABLE(of, ast2600_i3c_master_of_match);
176
177static 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};
185module_platform_driver(ast2600_i3c_driver);
186
187MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
188MODULE_DESCRIPTION("ASPEED AST2600 I3C driver");
189MODULE_LICENSE("GPL");