aboutsummaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-stp-xway.c
blob: e35096bf3cfb4f4faf1a46fed1ae79e2bd10e847 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
/*
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 *
 *  Copyright (C) 2012 John Crispin <blogic@openwrt.org>
 *
 */

#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/of_platform.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/of_gpio.h>
#include <linux/clk.h>
#include <linux/err.h>

#include <lantiq_soc.h>

/*
 * The Serial To Parallel (STP) is found on MIPS based Lantiq socs. It is a
 * peripheral controller used to drive external shift register cascades. At most
 * 3 groups of 8 bits can be driven. The hardware is able to allow the DSL modem
 * to drive the 2 LSBs of the cascade automatically.
 */

/* control register 0 */
#define XWAY_STP_CON0		0x00
/* control register 1 */
#define XWAY_STP_CON1		0x04
/* data register 0 */
#define XWAY_STP_CPU0		0x08
/* data register 1 */
#define XWAY_STP_CPU1		0x0C
/* access register */
#define XWAY_STP_AR		0x10

/* software or hardware update select bit */
#define XWAY_STP_CON_SWU	BIT(31)

/* automatic update rates */
#define XWAY_STP_2HZ		0
#define XWAY_STP_4HZ		BIT(23)
#define XWAY_STP_8HZ		BIT(24)
#define XWAY_STP_10HZ		(BIT(24) | BIT(23))
#define XWAY_STP_SPEED_MASK	(0xf << 23)

/* clock source for automatic update */
#define XWAY_STP_UPD_FPI	BIT(31)
#define XWAY_STP_UPD_MASK	(BIT(31) | BIT(30))

/* let the adsl core drive the 2 LSBs */
#define XWAY_STP_ADSL_SHIFT	24
#define XWAY_STP_ADSL_MASK	0x3

/* 2 groups of 3 bits can be driven by the phys */
#define XWAY_STP_PHY_MASK	0x3
#define XWAY_STP_PHY1_SHIFT	27
#define XWAY_STP_PHY2_SHIFT	15

/* STP has 3 groups of 8 bits */
#define XWAY_STP_GROUP0		BIT(0)
#define XWAY_STP_GROUP1		BIT(1)
#define XWAY_STP_GROUP2		BIT(2)
#define XWAY_STP_GROUP_MASK	(0x7)

/* Edge configuration bits */
#define XWAY_STP_FALLING	BIT(26)
#define XWAY_STP_EDGE_MASK	BIT(26)

#define xway_stp_r32(m, reg)		__raw_readl(m + reg)
#define xway_stp_w32(m, val, reg)	__raw_writel(val, m + reg)
#define xway_stp_w32_mask(m, clear, set, reg) \
		ltq_w32((ltq_r32(m + reg) & ~(clear)) | (set), \
		m + reg)

struct xway_stp {
	struct gpio_chip gc;
	void __iomem *virt;
	u32 edge;	/* rising or falling edge triggered shift register */
	u16 shadow;	/* shadow the shift registers state */
	u8 groups;	/* we can drive 1-3 groups of 8bit each */
	u8 dsl;		/* the 2 LSBs can be driven by the dsl core */
	u8 phy1;	/* 3 bits can be driven by phy1 */
	u8 phy2;	/* 3 bits can be driven by phy2 */
	u8 reserved;	/* mask out the hw driven bits in gpio_request */
};

/**
 * xway_stp_set() - gpio_chip->set - set gpios.
 * @gc:     Pointer to gpio_chip device structure.
 * @gpio:   GPIO signal number.
 * @val:    Value to be written to specified signal.
 *
 * Set the shadow value and call ltq_ebu_apply.
 */
static void xway_stp_set(struct gpio_chip *gc, unsigned gpio, int val)
{
	struct xway_stp *chip =
		container_of(gc, struct xway_stp, gc);

	if (val)
		chip->shadow |= BIT(gpio);
	else
		chip->shadow &= ~BIT(gpio);
	xway_stp_w32(chip->virt, chip->shadow, XWAY_STP_CPU0);
	xway_stp_w32_mask(chip->virt, 0, XWAY_STP_CON_SWU, XWAY_STP_CON0);
}

/**
 * xway_stp_dir_out() - gpio_chip->dir_out - set gpio direction.
 * @gc:     Pointer to gpio_chip device structure.
 * @gpio:   GPIO signal number.
 * @val:    Value to be written to specified signal.
 *
 * Same as xway_stp_set, always returns 0.
 */
static int xway_stp_dir_out(struct gpio_chip *gc, unsigned gpio, int val)
{
	xway_stp_set(gc, gpio, val);

	return 0;
}

/**
 * xway_stp_request() - gpio_chip->request
 * @gc:     Pointer to gpio_chip device structure.
 * @gpio:   GPIO signal number.
 *
 * We mask out the HW driven pins
 */
static int xway_stp_request(struct gpio_chip *gc, unsigned gpio)
{
	struct xway_stp *chip =
		container_of(gc, struct xway_stp, gc);

	if ((gpio < 8) && (chip->reserved & BIT(gpio))) {
		dev_err(gc->dev, "GPIO %d is driven by hardware\n", gpio);
		return -ENODEV;
	}

	return 0;
}

/**
 * xway_stp_hw_init() - Configure the STP unit and enable the clock gate
 * @virt: pointer to the remapped register range
 */
static int xway_stp_hw_init(struct xway_stp *chip)
{
	/* sane defaults */
	xway_stp_w32(chip->virt, 0, XWAY_STP_AR);
	xway_stp_w32(chip->virt, 0, XWAY_STP_CPU0);
	xway_stp_w32(chip->virt, 0, XWAY_STP_CPU1);
	xway_stp_w32(chip->virt, XWAY_STP_CON_SWU, XWAY_STP_CON0);
	xway_stp_w32(chip->virt, 0, XWAY_STP_CON1);

	/* apply edge trigger settings for the shift register */
	xway_stp_w32_mask(chip->virt, XWAY_STP_EDGE_MASK,
				chip->edge, XWAY_STP_CON0);

	/* apply led group settings */
	xway_stp_w32_mask(chip->virt, XWAY_STP_GROUP_MASK,
				chip->groups, XWAY_STP_CON1);

	/* tell the hardware which pins are controlled by the dsl modem */
	xway_stp_w32_mask(chip->virt,
			XWAY_STP_ADSL_MASK << XWAY_STP_ADSL_SHIFT,
			chip->dsl << XWAY_STP_ADSL_SHIFT,
			XWAY_STP_CON0);

	/* tell the hardware which pins are controlled by the phys */
	xway_stp_w32_mask(chip->virt,
			XWAY_STP_PHY_MASK << XWAY_STP_PHY1_SHIFT,
			chip->phy1 << XWAY_STP_PHY1_SHIFT,
			XWAY_STP_CON0);
	xway_stp_w32_mask(chip->virt,
			XWAY_STP_PHY_MASK << XWAY_STP_PHY2_SHIFT,
			chip->phy2 << XWAY_STP_PHY2_SHIFT,
			XWAY_STP_CON1);

	/* mask out the hw driven bits in gpio_request */
	chip->reserved = (chip->phy2 << 5) | (chip->phy1 << 2) | chip->dsl;

	/*
	 * if we have pins that are driven by hw, we need to tell the stp what
	 * clock to use as a timer.
	 */
	if (chip->reserved)
		xway_stp_w32_mask(chip->virt, XWAY_STP_UPD_MASK,
			XWAY_STP_UPD_FPI, XWAY_STP_CON1);

	return 0;
}

static int __devinit xway_stp_probe(struct platform_device *pdev)
{
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	const __be32 *shadow, *groups, *dsl, *phy;
	struct xway_stp *chip;
	struct clk *clk;
	int ret = 0;

	if (!res) {
		dev_err(&pdev->dev, "failed to request STP resource\n");
		return -ENOENT;
	}

	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
	if (!chip)
		return -ENOMEM;

	chip->virt = devm_request_and_ioremap(&pdev->dev, res);
	if (!chip->virt) {
		dev_err(&pdev->dev, "failed to remap STP memory\n");
		return -ENOMEM;
	}
	chip->gc.dev = &pdev->dev;
	chip->gc.label = "stp-xway";
	chip->gc.direction_output = xway_stp_dir_out;
	chip->gc.set = xway_stp_set;
	chip->gc.request = xway_stp_request;
	chip->gc.base = -1;
	chip->gc.owner = THIS_MODULE;

	/* store the shadow value if one was passed by the devicetree */
	shadow = of_get_property(pdev->dev.of_node, "lantiq,shadow", NULL);
	if (shadow)
		chip->shadow = be32_to_cpu(*shadow);

	/* find out which gpio groups should be enabled */
	groups = of_get_property(pdev->dev.of_node, "lantiq,groups", NULL);
	if (groups)
		chip->groups = be32_to_cpu(*groups) & XWAY_STP_GROUP_MASK;
	else
		chip->groups = XWAY_STP_GROUP0;
	chip->gc.ngpio = fls(chip->groups) * 8;

	/* find out which gpios are controlled by the dsl core */
	dsl = of_get_property(pdev->dev.of_node, "lantiq,dsl", NULL);
	if (dsl)
		chip->dsl = be32_to_cpu(*dsl) & XWAY_STP_ADSL_MASK;

	/* find out which gpios are controlled by the phys */
	if (of_machine_is_compatible("lantiq,ar9") ||
			of_machine_is_compatible("lantiq,gr9") ||
			of_machine_is_compatible("lantiq,vr9")) {
		phy = of_get_property(pdev->dev.of_node, "lantiq,phy1", NULL);
		if (phy)
			chip->phy1 = be32_to_cpu(*phy) & XWAY_STP_PHY_MASK;
		phy = of_get_property(pdev->dev.of_node, "lantiq,phy2", NULL);
		if (phy)
			chip->phy2 = be32_to_cpu(*phy) & XWAY_STP_PHY_MASK;
	}

	/* check which edge trigger we should use, default to a falling edge */
	if (!of_find_property(pdev->dev.of_node, "lantiq,rising", NULL))
		chip->edge = XWAY_STP_FALLING;

	clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "Failed to get clock\n");
		return PTR_ERR(clk);
	}
	clk_enable(clk);

	ret = xway_stp_hw_init(chip);
	if (!ret)
		ret = gpiochip_add(&chip->gc);

	if (!ret)
		dev_info(&pdev->dev, "Init done\n");

	return ret;
}

static const struct of_device_id xway_stp_match[] = {
	{ .compatible = "lantiq,gpio-stp-xway" },
	{},
};
MODULE_DEVICE_TABLE(of, xway_stp_match);

static struct platform_driver xway_stp_driver = {
	.probe = xway_stp_probe,
	.driver = {
		.name = "gpio-stp-xway",
		.owner = THIS_MODULE,
		.of_match_table = xway_stp_match,
	},
};

int __init xway_stp_init(void)
{
	return platform_driver_register(&xway_stp_driver);
}

subsys_initcall(xway_stp_init);