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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Copyright (C) 2012 John Crispin <john@phrozen.org>
5 */
6
7#include <linux/slab.h>
8#include <linux/init.h>
9#include <linux/module.h>
10#include <linux/types.h>
11#include <linux/of_platform.h>
12#include <linux/mutex.h>
13#include <linux/gpio/driver.h>
14#include <linux/io.h>
15#include <linux/clk.h>
16#include <linux/err.h>
17
18/*
19 * The Serial To Parallel (STP) is found on MIPS based Lantiq socs. It is a
20 * peripheral controller used to drive external shift register cascades. At most
21 * 3 groups of 8 bits can be driven. The hardware is able to allow the DSL modem
22 * to drive the 2 LSBs of the cascade automatically.
23 */
24
25/* control register 0 */
26#define XWAY_STP_CON0 0x00
27/* control register 1 */
28#define XWAY_STP_CON1 0x04
29/* data register 0 */
30#define XWAY_STP_CPU0 0x08
31/* data register 1 */
32#define XWAY_STP_CPU1 0x0C
33/* access register */
34#define XWAY_STP_AR 0x10
35
36/* software or hardware update select bit */
37#define XWAY_STP_CON_SWU BIT(31)
38
39/* automatic update rates */
40#define XWAY_STP_2HZ 0
41#define XWAY_STP_4HZ BIT(23)
42#define XWAY_STP_8HZ BIT(24)
43#define XWAY_STP_10HZ (BIT(24) | BIT(23))
44#define XWAY_STP_SPEED_MASK (BIT(23) | BIT(24) | BIT(25) | BIT(26) | BIT(27))
45
46#define XWAY_STP_FPIS_VALUE BIT(21)
47#define XWAY_STP_FPIS_MASK (BIT(20) | BIT(21))
48
49/* clock source for automatic update */
50#define XWAY_STP_UPD_FPI BIT(31)
51#define XWAY_STP_UPD_MASK (BIT(31) | BIT(30))
52
53/* let the adsl core drive the 2 LSBs */
54#define XWAY_STP_ADSL_SHIFT 24
55#define XWAY_STP_ADSL_MASK 0x3
56
57/* 2 groups of 3 bits can be driven by the phys */
58#define XWAY_STP_PHY_MASK 0x7
59#define XWAY_STP_PHY1_SHIFT 27
60#define XWAY_STP_PHY2_SHIFT 3
61#define XWAY_STP_PHY3_SHIFT 6
62#define XWAY_STP_PHY4_SHIFT 15
63
64/* STP has 3 groups of 8 bits */
65#define XWAY_STP_GROUP0 BIT(0)
66#define XWAY_STP_GROUP1 BIT(1)
67#define XWAY_STP_GROUP2 BIT(2)
68#define XWAY_STP_GROUP_MASK (0x7)
69
70/* Edge configuration bits */
71#define XWAY_STP_FALLING BIT(26)
72#define XWAY_STP_EDGE_MASK BIT(26)
73
74#define xway_stp_r32(m, reg) __raw_readl(m + reg)
75#define xway_stp_w32(m, val, reg) __raw_writel(val, m + reg)
76#define xway_stp_w32_mask(m, clear, set, reg) \
77 xway_stp_w32(m, (xway_stp_r32(m, reg) & ~(clear)) | (set), reg)
78
79struct xway_stp {
80 struct gpio_chip gc;
81 void __iomem *virt;
82 u32 edge; /* rising or falling edge triggered shift register */
83 u32 shadow; /* shadow the shift registers state */
84 u8 groups; /* we can drive 1-3 groups of 8bit each */
85 u8 dsl; /* the 2 LSBs can be driven by the dsl core */
86 u8 phy1; /* 3 bits can be driven by phy1 */
87 u8 phy2; /* 3 bits can be driven by phy2 */
88 u8 phy3; /* 3 bits can be driven by phy3 */
89 u8 phy4; /* 3 bits can be driven by phy4 */
90 u8 reserved; /* mask out the hw driven bits in gpio_request */
91};
92
93/**
94 * xway_stp_get() - gpio_chip->get - get gpios.
95 * @gc: Pointer to gpio_chip device structure.
96 * @gpio: GPIO signal number.
97 *
98 * Gets the shadow value.
99 */
100static int xway_stp_get(struct gpio_chip *gc, unsigned int gpio)
101{
102 struct xway_stp *chip = gpiochip_get_data(gc);
103
104 return (xway_stp_r32(chip->virt, XWAY_STP_CPU0) & BIT(gpio));
105}
106
107/**
108 * xway_stp_set() - gpio_chip->set - set gpios.
109 * @gc: Pointer to gpio_chip device structure.
110 * @gpio: GPIO signal number.
111 * @val: Value to be written to specified signal.
112 *
113 * Set the shadow value and call ltq_ebu_apply.
114 */
115static void xway_stp_set(struct gpio_chip *gc, unsigned gpio, int val)
116{
117 struct xway_stp *chip = gpiochip_get_data(gc);
118
119 if (val)
120 chip->shadow |= BIT(gpio);
121 else
122 chip->shadow &= ~BIT(gpio);
123 xway_stp_w32(chip->virt, chip->shadow, XWAY_STP_CPU0);
124 if (!chip->reserved)
125 xway_stp_w32_mask(chip->virt, 0, XWAY_STP_CON_SWU, XWAY_STP_CON0);
126}
127
128/**
129 * xway_stp_dir_out() - gpio_chip->dir_out - set gpio direction.
130 * @gc: Pointer to gpio_chip device structure.
131 * @gpio: GPIO signal number.
132 * @val: Value to be written to specified signal.
133 *
134 * Same as xway_stp_set, always returns 0.
135 */
136static int xway_stp_dir_out(struct gpio_chip *gc, unsigned gpio, int val)
137{
138 xway_stp_set(gc, gpio, val);
139
140 return 0;
141}
142
143/**
144 * xway_stp_request() - gpio_chip->request
145 * @gc: Pointer to gpio_chip device structure.
146 * @gpio: GPIO signal number.
147 *
148 * We mask out the HW driven pins
149 */
150static int xway_stp_request(struct gpio_chip *gc, unsigned gpio)
151{
152 struct xway_stp *chip = gpiochip_get_data(gc);
153
154 if ((gpio < 8) && (chip->reserved & BIT(gpio))) {
155 dev_err(gc->parent, "GPIO %d is driven by hardware\n", gpio);
156 return -ENODEV;
157 }
158
159 return 0;
160}
161
162/**
163 * xway_stp_hw_init() - Configure the STP unit and enable the clock gate
164 * @chip: Pointer to the xway_stp chip structure
165 */
166static void xway_stp_hw_init(struct xway_stp *chip)
167{
168 /* sane defaults */
169 xway_stp_w32(chip->virt, 0, XWAY_STP_AR);
170 xway_stp_w32(chip->virt, 0, XWAY_STP_CPU0);
171 xway_stp_w32(chip->virt, 0, XWAY_STP_CPU1);
172 xway_stp_w32(chip->virt, XWAY_STP_CON_SWU, XWAY_STP_CON0);
173 xway_stp_w32(chip->virt, 0, XWAY_STP_CON1);
174
175 /* apply edge trigger settings for the shift register */
176 xway_stp_w32_mask(chip->virt, XWAY_STP_EDGE_MASK,
177 chip->edge, XWAY_STP_CON0);
178
179 /* apply led group settings */
180 xway_stp_w32_mask(chip->virt, XWAY_STP_GROUP_MASK,
181 chip->groups, XWAY_STP_CON1);
182
183 /* tell the hardware which pins are controlled by the dsl modem */
184 xway_stp_w32_mask(chip->virt,
185 XWAY_STP_ADSL_MASK << XWAY_STP_ADSL_SHIFT,
186 chip->dsl << XWAY_STP_ADSL_SHIFT,
187 XWAY_STP_CON0);
188
189 /* tell the hardware which pins are controlled by the phys */
190 xway_stp_w32_mask(chip->virt,
191 XWAY_STP_PHY_MASK << XWAY_STP_PHY1_SHIFT,
192 chip->phy1 << XWAY_STP_PHY1_SHIFT,
193 XWAY_STP_CON0);
194 xway_stp_w32_mask(chip->virt,
195 XWAY_STP_PHY_MASK << XWAY_STP_PHY2_SHIFT,
196 chip->phy2 << XWAY_STP_PHY2_SHIFT,
197 XWAY_STP_CON1);
198
199 if (of_machine_is_compatible("lantiq,grx390")
200 || of_machine_is_compatible("lantiq,ar10")) {
201 xway_stp_w32_mask(chip->virt,
202 XWAY_STP_PHY_MASK << XWAY_STP_PHY3_SHIFT,
203 chip->phy3 << XWAY_STP_PHY3_SHIFT,
204 XWAY_STP_CON1);
205 }
206
207 if (of_machine_is_compatible("lantiq,grx390")) {
208 xway_stp_w32_mask(chip->virt,
209 XWAY_STP_PHY_MASK << XWAY_STP_PHY4_SHIFT,
210 chip->phy4 << XWAY_STP_PHY4_SHIFT,
211 XWAY_STP_CON1);
212 }
213
214 /* mask out the hw driven bits in gpio_request */
215 chip->reserved = (chip->phy4 << 11) | (chip->phy3 << 8) | (chip->phy2 << 5)
216 | (chip->phy1 << 2) | chip->dsl;
217
218 /*
219 * if we have pins that are driven by hw, we need to tell the stp what
220 * clock to use as a timer.
221 */
222 if (chip->reserved) {
223 xway_stp_w32_mask(chip->virt, XWAY_STP_UPD_MASK,
224 XWAY_STP_UPD_FPI, XWAY_STP_CON1);
225 xway_stp_w32_mask(chip->virt, XWAY_STP_SPEED_MASK,
226 XWAY_STP_10HZ, XWAY_STP_CON1);
227 xway_stp_w32_mask(chip->virt, XWAY_STP_FPIS_MASK,
228 XWAY_STP_FPIS_VALUE, XWAY_STP_CON1);
229 }
230}
231
232static int xway_stp_probe(struct platform_device *pdev)
233{
234 u32 shadow, groups, dsl, phy;
235 struct xway_stp *chip;
236 struct clk *clk;
237 int ret = 0;
238
239 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
240 if (!chip)
241 return -ENOMEM;
242
243 chip->virt = devm_platform_ioremap_resource(pdev, 0);
244 if (IS_ERR(chip->virt))
245 return PTR_ERR(chip->virt);
246
247 chip->gc.parent = &pdev->dev;
248 chip->gc.label = "stp-xway";
249 chip->gc.direction_output = xway_stp_dir_out;
250 chip->gc.get = xway_stp_get;
251 chip->gc.set = xway_stp_set;
252 chip->gc.request = xway_stp_request;
253 chip->gc.base = -1;
254 chip->gc.owner = THIS_MODULE;
255
256 /* store the shadow value if one was passed by the devicetree */
257 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,shadow", &shadow))
258 chip->shadow = shadow;
259
260 /* find out which gpio groups should be enabled */
261 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,groups", &groups))
262 chip->groups = groups & XWAY_STP_GROUP_MASK;
263 else
264 chip->groups = XWAY_STP_GROUP0;
265 chip->gc.ngpio = fls(chip->groups) * 8;
266
267 /* find out which gpios are controlled by the dsl core */
268 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,dsl", &dsl))
269 chip->dsl = dsl & XWAY_STP_ADSL_MASK;
270
271 /* find out which gpios are controlled by the phys */
272 if (of_machine_is_compatible("lantiq,ar9") ||
273 of_machine_is_compatible("lantiq,gr9") ||
274 of_machine_is_compatible("lantiq,vr9") ||
275 of_machine_is_compatible("lantiq,ar10") ||
276 of_machine_is_compatible("lantiq,grx390")) {
277 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy1", &phy))
278 chip->phy1 = phy & XWAY_STP_PHY_MASK;
279 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy2", &phy))
280 chip->phy2 = phy & XWAY_STP_PHY_MASK;
281 }
282
283 if (of_machine_is_compatible("lantiq,ar10") ||
284 of_machine_is_compatible("lantiq,grx390")) {
285 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy3", &phy))
286 chip->phy3 = phy & XWAY_STP_PHY_MASK;
287 }
288
289 if (of_machine_is_compatible("lantiq,grx390")) {
290 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy4", &phy))
291 chip->phy4 = phy & XWAY_STP_PHY_MASK;
292 }
293
294 /* check which edge trigger we should use, default to a falling edge */
295 if (!of_find_property(pdev->dev.of_node, "lantiq,rising", NULL))
296 chip->edge = XWAY_STP_FALLING;
297
298 clk = devm_clk_get(&pdev->dev, NULL);
299 if (IS_ERR(clk)) {
300 dev_err(&pdev->dev, "Failed to get clock\n");
301 return PTR_ERR(clk);
302 }
303
304 ret = clk_prepare_enable(clk);
305 if (ret)
306 return ret;
307
308 xway_stp_hw_init(chip);
309
310 ret = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
311 if (ret) {
312 clk_disable_unprepare(clk);
313 return ret;
314 }
315
316 dev_info(&pdev->dev, "Init done\n");
317
318 return 0;
319}
320
321static const struct of_device_id xway_stp_match[] = {
322 { .compatible = "lantiq,gpio-stp-xway" },
323 {},
324};
325MODULE_DEVICE_TABLE(of, xway_stp_match);
326
327static struct platform_driver xway_stp_driver = {
328 .probe = xway_stp_probe,
329 .driver = {
330 .name = "gpio-stp-xway",
331 .of_match_table = xway_stp_match,
332 },
333};
334
335static int __init xway_stp_init(void)
336{
337 return platform_driver_register(&xway_stp_driver);
338}
339
340subsys_initcall(xway_stp_init);