xref: /openbmc/u-boot/drivers/spmi/spmi-sandbox.c (revision 4aa2ba3a)
1 /*
2  * Sample SPMI bus driver
3  *
4  * It emulates bus with single pm8916-like pmic that has only GPIO reigsters.
5  *
6  * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
7  *
8  * SPDX-License-Identifier:	GPL-2.0+
9  */
10 
11 #include <common.h>
12 #include <dm.h>
13 #include <errno.h>
14 #include <spmi/spmi.h>
15 #include <asm/gpio.h>
16 #include <asm/io.h>
17 
18 DECLARE_GLOBAL_DATA_PTR;
19 
20 #define EMUL_GPIO_PID_START 0xC0
21 #define EMUL_GPIO_PID_END   0xC3
22 
23 #define EMUL_GPIO_COUNT 4
24 
25 #define EMUL_GPIO_REG_END 0x46 /* Last valid register */
26 
27 #define EMUL_PERM_R 0x1
28 #define EMUL_PERM_W 0x2
29 #define EMUL_PERM_RW (EMUL_PERM_R | EMUL_PERM_W)
30 
31 struct sandbox_emul_fake_regs {
32 	u8 value;
33 	u8 access_mask;
34 	u8 perms; /* Access permissions */
35 };
36 
37 struct sandbox_emul_gpio {
38 	/* Fake registers - need one more entry as REG_END is valid address. */
39 	struct sandbox_emul_fake_regs r[EMUL_GPIO_REG_END + 1];
40 };
41 
42 struct sandbox_spmi_priv {
43 	struct sandbox_emul_gpio gpios[EMUL_GPIO_COUNT];
44 };
45 
46 /* Check if valid register was requested */
47 static bool check_address_valid(int usid, int pid, int off)
48 {
49 	if (usid != 0)
50 		return false;
51 	if (pid < EMUL_GPIO_PID_START || pid > EMUL_GPIO_PID_END)
52 		return false;
53 	if (off > EMUL_GPIO_REG_END)
54 		return false;
55 	return true;
56 }
57 
58 static int sandbox_spmi_write(struct udevice *dev, int usid, int pid, int off,
59 			  uint8_t val)
60 {
61 	struct sandbox_spmi_priv *priv = dev_get_priv(dev);
62 	struct sandbox_emul_fake_regs *regs;
63 
64 	if (!check_address_valid(usid, pid, off))
65 		return -EIO;
66 
67 	regs = priv->gpios[pid & 0x3].r; /* Last 3 bits of pid are gpio # */
68 
69 	switch (off) {
70 	case 0x40: /* Control */
71 		val &= regs[off].access_mask;
72 		if (((val & 0x30) == 0x10) || ((val & 0x30) == 0x20)) {
73 			/* out/inout - set status register */
74 			regs[0x8].value &= ~0x1;
75 			regs[0x8].value |= val & 0x1;
76 		}
77 		break;
78 	default:
79 		if (regs[off].perms & EMUL_PERM_W)
80 			regs[off].value = val & regs[off].access_mask;
81 	}
82 	return 0;
83 }
84 
85 static int sandbox_spmi_read(struct udevice *dev, int usid, int pid, int off)
86 {
87 	struct sandbox_spmi_priv *priv = dev_get_priv(dev);
88 	struct sandbox_emul_fake_regs *regs;
89 
90 	if (!check_address_valid(usid, pid, off))
91 		return -EIO;
92 
93 	regs = priv->gpios[pid & 0x3].r; /* Last 3 bits of pid are gpio # */
94 
95 	if (regs[0x46].value == 0) /* Block disabled */
96 		return 0;
97 
98 	switch (off) {
99 	case 0x8: /* Status */
100 		if (regs[0x46].value == 0) /* Block disabled */
101 			return 0;
102 		return regs[off].value;
103 	default:
104 		if (regs[off].perms & EMUL_PERM_R)
105 			return regs[off].value;
106 		else
107 			return 0;
108 	}
109 }
110 
111 static struct dm_spmi_ops sandbox_spmi_ops = {
112 	.read = sandbox_spmi_read,
113 	.write = sandbox_spmi_write,
114 };
115 
116 static int sandbox_spmi_probe(struct udevice *dev)
117 {
118 	struct sandbox_spmi_priv *priv = dev_get_priv(dev);
119 	int i;
120 
121 	for (i = 0; i < EMUL_GPIO_COUNT; ++i) {
122 		struct sandbox_emul_fake_regs *regs = priv->gpios[i].r;
123 		regs[4].perms = EMUL_PERM_R;
124 		regs[4].value = 0x10;
125 		regs[5].perms = EMUL_PERM_R;
126 		regs[5].value = 0x5;
127 		regs[8].access_mask = 0x81;
128 		regs[8].perms = EMUL_PERM_RW;
129 		regs[0x40].access_mask = 0x7F;
130 		regs[0x40].perms = EMUL_PERM_RW;
131 		regs[0x41].access_mask = 7;
132 		regs[0x41].perms = EMUL_PERM_RW;
133 		regs[0x42].access_mask = 7;
134 		regs[0x42].perms = EMUL_PERM_RW;
135 		regs[0x42].value = 0x4;
136 		regs[0x45].access_mask = 0x3F;
137 		regs[0x45].perms = EMUL_PERM_RW;
138 		regs[0x45].value = 0x1;
139 		regs[0x46].access_mask = 0x80;
140 		regs[0x46].perms = EMUL_PERM_RW;
141 		regs[0x46].value = 0x80;
142 	}
143 	return 0;
144 }
145 
146 static const struct udevice_id sandbox_spmi_ids[] = {
147 	{ .compatible = "sandbox,spmi" },
148 	{ }
149 };
150 
151 U_BOOT_DRIVER(msm_spmi) = {
152 	.name = "sandbox_spmi",
153 	.id = UCLASS_SPMI,
154 	.of_match = sandbox_spmi_ids,
155 	.ops = &sandbox_spmi_ops,
156 	.probe = sandbox_spmi_probe,
157 	.priv_auto_alloc_size = sizeof(struct sandbox_spmi_priv),
158 };
159