1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2009,2010 One Laptop per Child
4 */
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/acpi.h>
9#include <linux/delay.h>
10#include <linux/i2c.h>
11#include <linux/gpio/consumer.h>
12#include <linux/gpio/machine.h>
13#include <asm/olpc.h>
14
15/* TODO: this eventually belongs in linux/vx855.h */
16#define NR_VX855_GPI 14
17#define NR_VX855_GPO 13
18#define NR_VX855_GPIO 15
19
20#define VX855_GPI(n) (n)
21#define VX855_GPO(n) (NR_VX855_GPI + (n))
22#define VX855_GPIO(n) (NR_VX855_GPI + NR_VX855_GPO + (n))
23
24#include "olpc_dcon.h"
25
26/* Hardware setup on the XO 1.5:
27 * DCONLOAD connects to VX855_GPIO1 (not SMBCK2)
28 * DCONBLANK connects to VX855_GPIO8 (not SSPICLK) unused in driver
29 * DCONSTAT0 connects to VX855_GPI10 (not SSPISDI)
30 * DCONSTAT1 connects to VX855_GPI11 (not nSSPISS)
31 * DCONIRQ connects to VX855_GPIO12
32 * DCONSMBDATA connects to VX855 graphics CRTSPD
33 * DCONSMBCLK connects to VX855 graphics CRTSPCLK
34 */
35
36#define VX855_GENL_PURPOSE_OUTPUT 0x44c /* PMIO_Rx4c-4f */
37#define VX855_GPI_STATUS_CHG 0x450 /* PMIO_Rx50 */
38#define VX855_GPI_SCI_SMI 0x452 /* PMIO_Rx52 */
39#define BIT_GPIO12 0x40
40
41#define PREFIX "OLPC DCON:"
42
43enum dcon_gpios {
44 OLPC_DCON_STAT0,
45 OLPC_DCON_STAT1,
46 OLPC_DCON_LOAD,
47};
48
49struct gpiod_lookup_table gpios_table = {
50 .dev_id = NULL,
51 .table = {
52 GPIO_LOOKUP("VX855 South Bridge", VX855_GPIO(1), "dcon_load",
53 GPIO_ACTIVE_LOW),
54 GPIO_LOOKUP("VX855 South Bridge", VX855_GPI(10), "dcon_stat0",
55 GPIO_ACTIVE_LOW),
56 GPIO_LOOKUP("VX855 South Bridge", VX855_GPI(11), "dcon_stat1",
57 GPIO_ACTIVE_LOW),
58 { },
59 },
60};
61
62static const struct dcon_gpio gpios_asis[] = {
63 [OLPC_DCON_STAT0] = { .name = "dcon_stat0", .flags = GPIOD_ASIS },
64 [OLPC_DCON_STAT1] = { .name = "dcon_stat1", .flags = GPIOD_ASIS },
65 [OLPC_DCON_LOAD] = { .name = "dcon_load", .flags = GPIOD_ASIS },
66};
67
68static struct gpio_desc *gpios[3];
69
70static void dcon_clear_irq(void)
71{
72 /* irq status will appear in PMIO_Rx50[6] (RW1C) on gpio12 */
73 outb(BIT_GPIO12, VX855_GPI_STATUS_CHG);
74}
75
76static int dcon_was_irq(void)
77{
78 u8 tmp;
79
80 /* irq status will appear in PMIO_Rx50[6] on gpio12 */
81 tmp = inb(VX855_GPI_STATUS_CHG);
82
83 return !!(tmp & BIT_GPIO12);
84}
85
86static int dcon_init_xo_1_5(struct dcon_priv *dcon)
87{
88 unsigned int irq;
89 const struct dcon_gpio *pin = &gpios_asis[0];
90 int i;
91 int ret;
92
93 /* Add GPIO look up table */
94 gpios_table.dev_id = dev_name(dev: &dcon->client->dev);
95 gpiod_add_lookup_table(table: &gpios_table);
96
97 /* Get GPIO descriptor */
98 for (i = 0; i < ARRAY_SIZE(gpios_asis); i++) {
99 gpios[i] = devm_gpiod_get(dev: &dcon->client->dev, con_id: pin[i].name,
100 flags: pin[i].flags);
101 if (IS_ERR(ptr: gpios[i])) {
102 ret = PTR_ERR(ptr: gpios[i]);
103 pr_err("failed to request %s GPIO: %d\n", pin[i].name,
104 ret);
105 return ret;
106 }
107 }
108
109 dcon_clear_irq();
110
111 /* set PMIO_Rx52[6] to enable SCI/SMI on gpio12 */
112 outb(inb(VX855_GPI_SCI_SMI) | BIT_GPIO12, VX855_GPI_SCI_SMI);
113
114 /* Determine the current state of DCONLOAD, likely set by firmware */
115 /* GPIO1 */
116 dcon->curr_src = (inl(VX855_GENL_PURPOSE_OUTPUT) & 0x1000) ?
117 DCON_SOURCE_CPU : DCON_SOURCE_DCON;
118 dcon->pending_src = dcon->curr_src;
119
120 /* we're sharing the IRQ with ACPI */
121 irq = acpi_gbl_FADT.sci_interrupt;
122 if (request_irq(irq, handler: &dcon_interrupt, IRQF_SHARED, name: "DCON", dev: dcon)) {
123 pr_err("DCON (IRQ%d) allocation failed\n", irq);
124 return 1;
125 }
126
127 return 0;
128}
129
130static void set_i2c_line(int sda, int scl)
131{
132 unsigned char tmp;
133 unsigned int port = 0x26;
134
135 /* FIXME: This directly accesses the CRT GPIO controller !!! */
136 outb(value: port, port: 0x3c4);
137 tmp = inb(port: 0x3c5);
138
139 if (scl)
140 tmp |= 0x20;
141 else
142 tmp &= ~0x20;
143
144 if (sda)
145 tmp |= 0x10;
146 else
147 tmp &= ~0x10;
148
149 tmp |= 0x01;
150
151 outb(value: port, port: 0x3c4);
152 outb(value: tmp, port: 0x3c5);
153}
154
155static void dcon_wiggle_xo_1_5(void)
156{
157 int x;
158
159 /*
160 * According to HiMax, when powering the DCON up we should hold
161 * SMB_DATA high for 8 SMB_CLK cycles. This will force the DCON
162 * state machine to reset to a (sane) initial state. Mitch Bradley
163 * did some testing and discovered that holding for 16 SMB_CLK cycles
164 * worked a lot more reliably, so that's what we do here.
165 */
166 set_i2c_line(sda: 1, scl: 1);
167
168 for (x = 0; x < 16; x++) {
169 udelay(5);
170 set_i2c_line(sda: 1, scl: 0);
171 udelay(5);
172 set_i2c_line(sda: 1, scl: 1);
173 }
174 udelay(5);
175
176 /* set PMIO_Rx52[6] to enable SCI/SMI on gpio12 */
177 outb(inb(VX855_GPI_SCI_SMI) | BIT_GPIO12, VX855_GPI_SCI_SMI);
178}
179
180static void dcon_set_dconload_xo_1_5(int val)
181{
182 gpiod_set_value(desc: gpios[OLPC_DCON_LOAD], value: val);
183}
184
185static int dcon_read_status_xo_1_5(u8 *status)
186{
187 if (!dcon_was_irq())
188 return -1;
189
190 /* i believe this is the same as "inb(0x44b) & 3" */
191 *status = gpiod_get_value(desc: gpios[OLPC_DCON_STAT0]);
192 *status |= gpiod_get_value(desc: gpios[OLPC_DCON_STAT1]) << 1;
193
194 dcon_clear_irq();
195
196 return 0;
197}
198
199struct dcon_platform_data dcon_pdata_xo_1_5 = {
200 .init = dcon_init_xo_1_5,
201 .bus_stabilize_wiggle = dcon_wiggle_xo_1_5,
202 .set_dconload = dcon_set_dconload_xo_1_5,
203 .read_status = dcon_read_status_xo_1_5,
204};
205

source code of linux/drivers/staging/olpc_dcon/olpc_dcon_xo_1_5.c