xref: /openbmc/linux/drivers/i2c/busses/i2c-hydra.c (revision c942fddf)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3     i2c Support for the Apple `Hydra' Mac I/O
4 
5     Copyright (c) 1999-2004 Geert Uytterhoeven <geert@linux-m68k.org>
6 
7     Based on i2c Support for Via Technologies 82C586B South Bridge
8     Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>
9 
10 */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/pci.h>
15 #include <linux/types.h>
16 #include <linux/i2c.h>
17 #include <linux/i2c-algo-bit.h>
18 #include <linux/io.h>
19 #include <asm/hydra.h>
20 
21 
22 #define HYDRA_CPD_PD0	0x00000001	/* CachePD lines */
23 #define HYDRA_CPD_PD1	0x00000002
24 #define HYDRA_CPD_PD2	0x00000004
25 #define HYDRA_CPD_PD3	0x00000008
26 
27 #define HYDRA_SCLK	HYDRA_CPD_PD0
28 #define HYDRA_SDAT	HYDRA_CPD_PD1
29 #define HYDRA_SCLK_OE	0x00000010
30 #define HYDRA_SDAT_OE	0x00000020
31 
pdregw(void * data,u32 val)32 static inline void pdregw(void *data, u32 val)
33 {
34 	struct Hydra *hydra = (struct Hydra *)data;
35 	writel(val, &hydra->CachePD);
36 }
37 
pdregr(void * data)38 static inline u32 pdregr(void *data)
39 {
40 	struct Hydra *hydra = (struct Hydra *)data;
41 	return readl(&hydra->CachePD);
42 }
43 
hydra_bit_setscl(void * data,int state)44 static void hydra_bit_setscl(void *data, int state)
45 {
46 	u32 val = pdregr(data);
47 	if (state)
48 		val &= ~HYDRA_SCLK_OE;
49 	else {
50 		val &= ~HYDRA_SCLK;
51 		val |= HYDRA_SCLK_OE;
52 	}
53 	pdregw(data, val);
54 }
55 
hydra_bit_setsda(void * data,int state)56 static void hydra_bit_setsda(void *data, int state)
57 {
58 	u32 val = pdregr(data);
59 	if (state)
60 		val &= ~HYDRA_SDAT_OE;
61 	else {
62 		val &= ~HYDRA_SDAT;
63 		val |= HYDRA_SDAT_OE;
64 	}
65 	pdregw(data, val);
66 }
67 
hydra_bit_getscl(void * data)68 static int hydra_bit_getscl(void *data)
69 {
70 	return (pdregr(data) & HYDRA_SCLK) != 0;
71 }
72 
hydra_bit_getsda(void * data)73 static int hydra_bit_getsda(void *data)
74 {
75 	return (pdregr(data) & HYDRA_SDAT) != 0;
76 }
77 
78 /* ------------------------------------------------------------------------ */
79 
80 static struct i2c_algo_bit_data hydra_bit_data = {
81 	.setsda		= hydra_bit_setsda,
82 	.setscl		= hydra_bit_setscl,
83 	.getsda		= hydra_bit_getsda,
84 	.getscl		= hydra_bit_getscl,
85 	.udelay		= 5,
86 	.timeout	= HZ
87 };
88 
89 static struct i2c_adapter hydra_adap = {
90 	.owner		= THIS_MODULE,
91 	.name		= "Hydra i2c",
92 	.algo_data	= &hydra_bit_data,
93 };
94 
95 static const struct pci_device_id hydra_ids[] = {
96 	{ PCI_DEVICE(PCI_VENDOR_ID_APPLE, PCI_DEVICE_ID_APPLE_HYDRA) },
97 	{ 0, }
98 };
99 
100 MODULE_DEVICE_TABLE (pci, hydra_ids);
101 
hydra_probe(struct pci_dev * dev,const struct pci_device_id * id)102 static int hydra_probe(struct pci_dev *dev,
103 				 const struct pci_device_id *id)
104 {
105 	unsigned long base = pci_resource_start(dev, 0);
106 	int res;
107 
108 	if (!request_mem_region(base+offsetof(struct Hydra, CachePD), 4,
109 				hydra_adap.name))
110 		return -EBUSY;
111 
112 	hydra_bit_data.data = pci_ioremap_bar(dev, 0);
113 	if (hydra_bit_data.data == NULL) {
114 		release_mem_region(base+offsetof(struct Hydra, CachePD), 4);
115 		return -ENODEV;
116 	}
117 
118 	pdregw(hydra_bit_data.data, 0);		/* clear SCLK_OE and SDAT_OE */
119 	hydra_adap.dev.parent = &dev->dev;
120 	res = i2c_bit_add_bus(&hydra_adap);
121 	if (res < 0) {
122 		iounmap(hydra_bit_data.data);
123 		release_mem_region(base+offsetof(struct Hydra, CachePD), 4);
124 		return res;
125 	}
126 	return 0;
127 }
128 
hydra_remove(struct pci_dev * dev)129 static void hydra_remove(struct pci_dev *dev)
130 {
131 	pdregw(hydra_bit_data.data, 0);		/* clear SCLK_OE and SDAT_OE */
132 	i2c_del_adapter(&hydra_adap);
133 	iounmap(hydra_bit_data.data);
134 	release_mem_region(pci_resource_start(dev, 0)+
135 			   offsetof(struct Hydra, CachePD), 4);
136 }
137 
138 
139 static struct pci_driver hydra_driver = {
140 	.name		= "hydra_smbus",
141 	.id_table	= hydra_ids,
142 	.probe		= hydra_probe,
143 	.remove		= hydra_remove,
144 };
145 
146 module_pci_driver(hydra_driver);
147 
148 MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
149 MODULE_DESCRIPTION("i2c for Apple Hydra Mac I/O");
150 MODULE_LICENSE("GPL");
151