1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * GPIO driver for AMD 8111 south bridges
4  *
5  * Copyright (c) 2012 Dmitry Eremin-Solenikov
6  *
7  * Based on the AMD RNG driver:
8  * Copyright 2005 (c) MontaVista Software, Inc.
9  * with the majority of the code coming from:
10  *
11  * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
12  * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
13  *
14  * derived from
15  *
16  * Hardware driver for the AMD 768 Random Number Generator (RNG)
17  * (c) Copyright 2001 Red Hat Inc
18  *
19  * derived from
20  *
21  * Hardware driver for Intel i810 Random Number Generator (RNG)
22  * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
23  * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
24  */
25 #include <linux/ioport.h>
26 #include <linux/module.h>
27 #include <linux/kernel.h>
28 #include <linux/gpio/driver.h>
29 #include <linux/pci.h>
30 #include <linux/spinlock.h>
31 
32 #define PMBASE_OFFSET 0xb0
33 #define PMBASE_SIZE   0x30
34 
35 #define AMD_REG_GPIO(i) (0x10 + (i))
36 
37 #define AMD_GPIO_LTCH_STS	0x40 /* Latch status, w1 */
38 #define AMD_GPIO_RTIN		0x20 /* Real Time in, ro */
39 #define AMD_GPIO_DEBOUNCE	0x10 /* Debounce, rw */
40 #define AMD_GPIO_MODE_MASK	0x0c /* Pin Mode Select, rw */
41 #define AMD_GPIO_MODE_IN	0x00
42 #define AMD_GPIO_MODE_OUT	0x04
43 /* Enable alternative (e.g. clkout, IRQ, etc) function of the pin */
44 #define AMD_GPIO_MODE_ALTFN	0x08 /* Or 0x09 */
45 #define AMD_GPIO_X_MASK		0x03 /* In/Out specific, rw */
46 #define AMD_GPIO_X_IN_ACTIVEHI	0x01 /* Active High */
47 #define AMD_GPIO_X_IN_LATCH	0x02 /* Latched version is selected */
48 #define AMD_GPIO_X_OUT_LOW	0x00
49 #define AMD_GPIO_X_OUT_HI	0x01
50 #define AMD_GPIO_X_OUT_CLK0	0x02
51 #define AMD_GPIO_X_OUT_CLK1	0x03
52 
53 /*
54  * Data for PCI driver interface
55  *
56  * This data only exists for exporting the supported
57  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
58  * register a pci_driver, because someone else might one day
59  * want to register another driver on the same PCI id.
60  */
61 static const struct pci_device_id pci_tbl[] = {
62 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8111_SMBUS), 0 },
63 	{ 0, },	/* terminate list */
64 };
65 MODULE_DEVICE_TABLE(pci, pci_tbl);
66 
67 struct amd_gpio {
68 	struct gpio_chip	chip;
69 	u32			pmbase;
70 	void __iomem		*pm;
71 	struct pci_dev		*pdev;
72 	spinlock_t		lock; /* guards hw registers and orig table */
73 	u8			orig[32];
74 };
75 
amd_gpio_request(struct gpio_chip * chip,unsigned offset)76 static int amd_gpio_request(struct gpio_chip *chip, unsigned offset)
77 {
78 	struct amd_gpio *agp = gpiochip_get_data(chip);
79 
80 	agp->orig[offset] = ioread8(agp->pm + AMD_REG_GPIO(offset)) &
81 		(AMD_GPIO_DEBOUNCE | AMD_GPIO_MODE_MASK | AMD_GPIO_X_MASK);
82 
83 	dev_dbg(&agp->pdev->dev, "Requested gpio %d, data %x\n", offset, agp->orig[offset]);
84 
85 	return 0;
86 }
87 
amd_gpio_free(struct gpio_chip * chip,unsigned offset)88 static void amd_gpio_free(struct gpio_chip *chip, unsigned offset)
89 {
90 	struct amd_gpio *agp = gpiochip_get_data(chip);
91 
92 	dev_dbg(&agp->pdev->dev, "Freed gpio %d, data %x\n", offset, agp->orig[offset]);
93 
94 	iowrite8(agp->orig[offset], agp->pm + AMD_REG_GPIO(offset));
95 }
96 
amd_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)97 static int amd_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
98 {
99 	struct amd_gpio *agp = gpiochip_get_data(chip);
100 	u8 temp;
101 	unsigned long flags;
102 
103 	spin_lock_irqsave(&agp->lock, flags);
104 	temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
105 	temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_OUT | (value ? AMD_GPIO_X_OUT_HI : AMD_GPIO_X_OUT_LOW);
106 	iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
107 	spin_unlock_irqrestore(&agp->lock, flags);
108 
109 	dev_dbg(&agp->pdev->dev, "Setting gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
110 
111 	return 0;
112 }
113 
amd_gpio_get(struct gpio_chip * chip,unsigned offset)114 static int amd_gpio_get(struct gpio_chip *chip, unsigned offset)
115 {
116 	struct amd_gpio *agp = gpiochip_get_data(chip);
117 	u8 temp;
118 
119 	temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
120 
121 	dev_dbg(&agp->pdev->dev, "Getting gpio %d, reg=%02x\n", offset, temp);
122 
123 	return (temp & AMD_GPIO_RTIN) ? 1 : 0;
124 }
125 
amd_gpio_dirout(struct gpio_chip * chip,unsigned offset,int value)126 static int amd_gpio_dirout(struct gpio_chip *chip, unsigned offset, int value)
127 {
128 	struct amd_gpio *agp = gpiochip_get_data(chip);
129 	u8 temp;
130 	unsigned long flags;
131 
132 	spin_lock_irqsave(&agp->lock, flags);
133 	temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
134 	temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_OUT | (value ? AMD_GPIO_X_OUT_HI : AMD_GPIO_X_OUT_LOW);
135 	iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
136 	spin_unlock_irqrestore(&agp->lock, flags);
137 
138 	dev_dbg(&agp->pdev->dev, "Dirout gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
139 
140 	return 0;
141 }
142 
amd_gpio_dirin(struct gpio_chip * chip,unsigned offset)143 static int amd_gpio_dirin(struct gpio_chip *chip, unsigned offset)
144 {
145 	struct amd_gpio *agp = gpiochip_get_data(chip);
146 	u8 temp;
147 	unsigned long flags;
148 
149 	spin_lock_irqsave(&agp->lock, flags);
150 	temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
151 	temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_IN;
152 	iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
153 	spin_unlock_irqrestore(&agp->lock, flags);
154 
155 	dev_dbg(&agp->pdev->dev, "Dirin gpio %d, reg=%02x\n", offset, temp);
156 
157 	return 0;
158 }
159 
160 static struct amd_gpio gp = {
161 	.chip = {
162 		.label		= "AMD GPIO",
163 		.owner		= THIS_MODULE,
164 		.base		= -1,
165 		.ngpio		= 32,
166 		.request	= amd_gpio_request,
167 		.free		= amd_gpio_free,
168 		.set_rv		= amd_gpio_set,
169 		.get		= amd_gpio_get,
170 		.direction_output = amd_gpio_dirout,
171 		.direction_input = amd_gpio_dirin,
172 	},
173 };
174 
amd_gpio_init(void)175 static int __init amd_gpio_init(void)
176 {
177 	int err = -ENODEV;
178 	struct pci_dev *pdev = NULL;
179 	const struct pci_device_id *ent;
180 
181 	/* We look for our device - AMD South Bridge
182 	 * I don't know about a system with two such bridges,
183 	 * so we can assume that there is max. one device.
184 	 *
185 	 * We can't use plain pci_driver mechanism,
186 	 * as the device is really a multiple function device,
187 	 * main driver that binds to the pci_device is an smbus
188 	 * driver and have to find & bind to the device this way.
189 	 */
190 	for_each_pci_dev(pdev) {
191 		ent = pci_match_id(pci_tbl, pdev);
192 		if (ent)
193 			goto found;
194 	}
195 	/* Device not found. */
196 	goto out;
197 
198 found:
199 	err = pci_read_config_dword(pdev, 0x58, &gp.pmbase);
200 	if (err) {
201 		err = pcibios_err_to_errno(err);
202 		goto out;
203 	}
204 	err = -EIO;
205 	gp.pmbase &= 0x0000FF00;
206 	if (gp.pmbase == 0)
207 		goto out;
208 	if (!devm_request_region(&pdev->dev, gp.pmbase + PMBASE_OFFSET,
209 		PMBASE_SIZE, "AMD GPIO")) {
210 		dev_err(&pdev->dev, "AMD GPIO region 0x%x already in use!\n",
211 			gp.pmbase + PMBASE_OFFSET);
212 		err = -EBUSY;
213 		goto out;
214 	}
215 	gp.pm = ioport_map(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE);
216 	if (!gp.pm) {
217 		dev_err(&pdev->dev, "Couldn't map io port into io memory\n");
218 		err = -ENOMEM;
219 		goto out;
220 	}
221 	gp.pdev = pdev;
222 	gp.chip.parent = &pdev->dev;
223 
224 	spin_lock_init(&gp.lock);
225 
226 	dev_info(&pdev->dev, "AMD-8111 GPIO detected\n");
227 	err = gpiochip_add_data(&gp.chip, &gp);
228 	if (err) {
229 		dev_err(&pdev->dev, "GPIO registering failed (%d)\n", err);
230 		ioport_unmap(gp.pm);
231 		goto out;
232 	}
233 	return 0;
234 
235 out:
236 	pci_dev_put(pdev);
237 	return err;
238 }
239 
amd_gpio_exit(void)240 static void __exit amd_gpio_exit(void)
241 {
242 	gpiochip_remove(&gp.chip);
243 	ioport_unmap(gp.pm);
244 	pci_dev_put(gp.pdev);
245 }
246 
247 module_init(amd_gpio_init);
248 module_exit(amd_gpio_exit);
249 
250 MODULE_AUTHOR("The Linux Kernel team");
251 MODULE_DESCRIPTION("GPIO driver for AMD chipsets");
252 MODULE_LICENSE("GPL");
253