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
41struct 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
48static struct ast2600_i3c *to_ast2600_i3c(struct dw_i3c_master *dw)
49{
50	return container_of(dw, struct ast2600_i3c, dw);
51}
52
53static 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
77static 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, &reg);
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
103static 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
120static 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
125static 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	i3c->dw.ibi_capable = true;
160	return dw_i3c_common_probe(&i3c->dw, pdev);
161}
162
163static void ast2600_i3c_remove(struct platform_device *pdev)
164{
165	struct dw_i3c_master *dw_i3c = platform_get_drvdata(pdev);
166
167	dw_i3c_common_remove(dw_i3c);
168}
169
170static const struct of_device_id ast2600_i3c_master_of_match[] = {
171	{ .compatible = "aspeed,ast2600-i3c", },
172	{},
173};
174MODULE_DEVICE_TABLE(of, ast2600_i3c_master_of_match);
175
176static struct platform_driver ast2600_i3c_driver = {
177	.probe = ast2600_i3c_probe,
178	.remove_new = ast2600_i3c_remove,
179	.driver = {
180		.name = "ast2600-i3c-master",
181		.of_match_table = ast2600_i3c_master_of_match,
182	},
183};
184module_platform_driver(ast2600_i3c_driver);
185
186MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");
187MODULE_DESCRIPTION("ASPEED AST2600 I3C driver");
188MODULE_LICENSE("GPL");
189