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935c500c JC |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify it | |
3 | * under the terms of the GNU General Public License version 2 as published | |
4 | * by the Free Software Foundation. | |
5 | * | |
54f30066 | 6 | * Copyright (C) 2012 John Crispin <[email protected]> |
935c500c JC |
7 | * |
8 | */ | |
9 | ||
10 | #include <linux/slab.h> | |
11 | #include <linux/init.h> | |
54f30066 | 12 | #include <linux/module.h> |
935c500c | 13 | #include <linux/types.h> |
54f30066 | 14 | #include <linux/of_platform.h> |
935c500c | 15 | #include <linux/mutex.h> |
935c500c | 16 | #include <linux/gpio.h> |
54f30066 JC |
17 | #include <linux/io.h> |
18 | #include <linux/of_gpio.h> | |
19 | #include <linux/clk.h> | |
20 | #include <linux/err.h> | |
935c500c JC |
21 | |
22 | #include <lantiq_soc.h> | |
23 | ||
54f30066 JC |
24 | /* |
25 | * The Serial To Parallel (STP) is found on MIPS based Lantiq socs. It is a | |
26 | * peripheral controller used to drive external shift register cascades. At most | |
27 | * 3 groups of 8 bits can be driven. The hardware is able to allow the DSL modem | |
28 | * to drive the 2 LSBs of the cascade automatically. | |
29 | */ | |
30 | ||
31 | /* control register 0 */ | |
32 | #define XWAY_STP_CON0 0x00 | |
33 | /* control register 1 */ | |
34 | #define XWAY_STP_CON1 0x04 | |
35 | /* data register 0 */ | |
36 | #define XWAY_STP_CPU0 0x08 | |
37 | /* data register 1 */ | |
38 | #define XWAY_STP_CPU1 0x0C | |
39 | /* access register */ | |
40 | #define XWAY_STP_AR 0x10 | |
41 | ||
42 | /* software or hardware update select bit */ | |
43 | #define XWAY_STP_CON_SWU BIT(31) | |
44 | ||
45 | /* automatic update rates */ | |
46 | #define XWAY_STP_2HZ 0 | |
47 | #define XWAY_STP_4HZ BIT(23) | |
48 | #define XWAY_STP_8HZ BIT(24) | |
49 | #define XWAY_STP_10HZ (BIT(24) | BIT(23)) | |
50 | #define XWAY_STP_SPEED_MASK (0xf << 23) | |
51 | ||
52 | /* clock source for automatic update */ | |
53 | #define XWAY_STP_UPD_FPI BIT(31) | |
54 | #define XWAY_STP_UPD_MASK (BIT(31) | BIT(30)) | |
55 | ||
56 | /* let the adsl core drive the 2 LSBs */ | |
57 | #define XWAY_STP_ADSL_SHIFT 24 | |
58 | #define XWAY_STP_ADSL_MASK 0x3 | |
59 | ||
60 | /* 2 groups of 3 bits can be driven by the phys */ | |
61 | #define XWAY_STP_PHY_MASK 0x3 | |
62 | #define XWAY_STP_PHY1_SHIFT 27 | |
63 | #define XWAY_STP_PHY2_SHIFT 15 | |
64 | ||
65 | /* STP has 3 groups of 8 bits */ | |
66 | #define XWAY_STP_GROUP0 BIT(0) | |
67 | #define XWAY_STP_GROUP1 BIT(1) | |
68 | #define XWAY_STP_GROUP2 BIT(2) | |
69 | #define XWAY_STP_GROUP_MASK (0x7) | |
70 | ||
71 | /* Edge configuration bits */ | |
72 | #define XWAY_STP_FALLING BIT(26) | |
73 | #define XWAY_STP_EDGE_MASK BIT(26) | |
74 | ||
75 | #define xway_stp_r32(m, reg) __raw_readl(m + reg) | |
76 | #define xway_stp_w32(m, val, reg) __raw_writel(val, m + reg) | |
77 | #define xway_stp_w32_mask(m, clear, set, reg) \ | |
78 | ltq_w32((ltq_r32(m + reg) & ~(clear)) | (set), \ | |
79 | m + reg) | |
80 | ||
81 | struct xway_stp { | |
82 | struct gpio_chip gc; | |
83 | void __iomem *virt; | |
84 | u32 edge; /* rising or falling edge triggered shift register */ | |
c9e854cf | 85 | u32 shadow; /* shadow the shift registers state */ |
54f30066 JC |
86 | u8 groups; /* we can drive 1-3 groups of 8bit each */ |
87 | u8 dsl; /* the 2 LSBs can be driven by the dsl core */ | |
88 | u8 phy1; /* 3 bits can be driven by phy1 */ | |
89 | u8 phy2; /* 3 bits can be driven by phy2 */ | |
90 | u8 reserved; /* mask out the hw driven bits in gpio_request */ | |
91 | }; | |
92 | ||
93 | /** | |
94 | * xway_stp_set() - gpio_chip->set - set gpios. | |
95 | * @gc: Pointer to gpio_chip device structure. | |
96 | * @gpio: GPIO signal number. | |
97 | * @val: Value to be written to specified signal. | |
98 | * | |
99 | * Set the shadow value and call ltq_ebu_apply. | |
100 | */ | |
101 | static void xway_stp_set(struct gpio_chip *gc, unsigned gpio, int val) | |
935c500c | 102 | { |
54f30066 JC |
103 | struct xway_stp *chip = |
104 | container_of(gc, struct xway_stp, gc); | |
105 | ||
106 | if (val) | |
107 | chip->shadow |= BIT(gpio); | |
935c500c | 108 | else |
54f30066 JC |
109 | chip->shadow &= ~BIT(gpio); |
110 | xway_stp_w32(chip->virt, chip->shadow, XWAY_STP_CPU0); | |
111 | xway_stp_w32_mask(chip->virt, 0, XWAY_STP_CON_SWU, XWAY_STP_CON0); | |
935c500c JC |
112 | } |
113 | ||
54f30066 JC |
114 | /** |
115 | * xway_stp_dir_out() - gpio_chip->dir_out - set gpio direction. | |
116 | * @gc: Pointer to gpio_chip device structure. | |
117 | * @gpio: GPIO signal number. | |
118 | * @val: Value to be written to specified signal. | |
119 | * | |
120 | * Same as xway_stp_set, always returns 0. | |
121 | */ | |
122 | static int xway_stp_dir_out(struct gpio_chip *gc, unsigned gpio, int val) | |
935c500c | 123 | { |
54f30066 | 124 | xway_stp_set(gc, gpio, val); |
935c500c JC |
125 | |
126 | return 0; | |
127 | } | |
128 | ||
54f30066 JC |
129 | /** |
130 | * xway_stp_request() - gpio_chip->request | |
131 | * @gc: Pointer to gpio_chip device structure. | |
132 | * @gpio: GPIO signal number. | |
133 | * | |
134 | * We mask out the HW driven pins | |
135 | */ | |
136 | static int xway_stp_request(struct gpio_chip *gc, unsigned gpio) | |
137 | { | |
138 | struct xway_stp *chip = | |
139 | container_of(gc, struct xway_stp, gc); | |
140 | ||
141 | if ((gpio < 8) && (chip->reserved & BIT(gpio))) { | |
142 | dev_err(gc->dev, "GPIO %d is driven by hardware\n", gpio); | |
143 | return -ENODEV; | |
144 | } | |
935c500c | 145 | |
54f30066 JC |
146 | return 0; |
147 | } | |
148 | ||
149 | /** | |
150 | * xway_stp_hw_init() - Configure the STP unit and enable the clock gate | |
151 | * @virt: pointer to the remapped register range | |
152 | */ | |
153 | static int xway_stp_hw_init(struct xway_stp *chip) | |
935c500c | 154 | { |
935c500c | 155 | /* sane defaults */ |
54f30066 JC |
156 | xway_stp_w32(chip->virt, 0, XWAY_STP_AR); |
157 | xway_stp_w32(chip->virt, 0, XWAY_STP_CPU0); | |
158 | xway_stp_w32(chip->virt, 0, XWAY_STP_CPU1); | |
159 | xway_stp_w32(chip->virt, XWAY_STP_CON_SWU, XWAY_STP_CON0); | |
160 | xway_stp_w32(chip->virt, 0, XWAY_STP_CON1); | |
935c500c | 161 | |
54f30066 JC |
162 | /* apply edge trigger settings for the shift register */ |
163 | xway_stp_w32_mask(chip->virt, XWAY_STP_EDGE_MASK, | |
164 | chip->edge, XWAY_STP_CON0); | |
935c500c | 165 | |
54f30066 JC |
166 | /* apply led group settings */ |
167 | xway_stp_w32_mask(chip->virt, XWAY_STP_GROUP_MASK, | |
168 | chip->groups, XWAY_STP_CON1); | |
935c500c | 169 | |
54f30066 JC |
170 | /* tell the hardware which pins are controlled by the dsl modem */ |
171 | xway_stp_w32_mask(chip->virt, | |
172 | XWAY_STP_ADSL_MASK << XWAY_STP_ADSL_SHIFT, | |
173 | chip->dsl << XWAY_STP_ADSL_SHIFT, | |
174 | XWAY_STP_CON0); | |
935c500c | 175 | |
54f30066 JC |
176 | /* tell the hardware which pins are controlled by the phys */ |
177 | xway_stp_w32_mask(chip->virt, | |
178 | XWAY_STP_PHY_MASK << XWAY_STP_PHY1_SHIFT, | |
179 | chip->phy1 << XWAY_STP_PHY1_SHIFT, | |
180 | XWAY_STP_CON0); | |
181 | xway_stp_w32_mask(chip->virt, | |
182 | XWAY_STP_PHY_MASK << XWAY_STP_PHY2_SHIFT, | |
183 | chip->phy2 << XWAY_STP_PHY2_SHIFT, | |
184 | XWAY_STP_CON1); | |
935c500c | 185 | |
54f30066 JC |
186 | /* mask out the hw driven bits in gpio_request */ |
187 | chip->reserved = (chip->phy2 << 5) | (chip->phy1 << 2) | chip->dsl; | |
188 | ||
189 | /* | |
190 | * if we have pins that are driven by hw, we need to tell the stp what | |
191 | * clock to use as a timer. | |
935c500c | 192 | */ |
54f30066 JC |
193 | if (chip->reserved) |
194 | xway_stp_w32_mask(chip->virt, XWAY_STP_UPD_MASK, | |
195 | XWAY_STP_UPD_FPI, XWAY_STP_CON1); | |
935c500c | 196 | |
935c500c JC |
197 | return 0; |
198 | } | |
199 | ||
3836309d | 200 | static int xway_stp_probe(struct platform_device *pdev) |
935c500c JC |
201 | { |
202 | struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
54f30066 JC |
203 | const __be32 *shadow, *groups, *dsl, *phy; |
204 | struct xway_stp *chip; | |
205 | struct clk *clk; | |
935c500c JC |
206 | int ret = 0; |
207 | ||
935c500c | 208 | if (!res) { |
54f30066 JC |
209 | dev_err(&pdev->dev, "failed to request STP resource\n"); |
210 | return -ENOENT; | |
935c500c | 211 | } |
54f30066 JC |
212 | |
213 | chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); | |
214 | if (!chip) | |
215 | return -ENOMEM; | |
216 | ||
641d0342 TR |
217 | chip->virt = devm_ioremap_resource(&pdev->dev, res); |
218 | if (IS_ERR(chip->virt)) | |
219 | return PTR_ERR(chip->virt); | |
8ab2a6d2 | 220 | |
54f30066 JC |
221 | chip->gc.dev = &pdev->dev; |
222 | chip->gc.label = "stp-xway"; | |
223 | chip->gc.direction_output = xway_stp_dir_out; | |
224 | chip->gc.set = xway_stp_set; | |
225 | chip->gc.request = xway_stp_request; | |
226 | chip->gc.base = -1; | |
227 | chip->gc.owner = THIS_MODULE; | |
228 | ||
229 | /* store the shadow value if one was passed by the devicetree */ | |
230 | shadow = of_get_property(pdev->dev.of_node, "lantiq,shadow", NULL); | |
231 | if (shadow) | |
232 | chip->shadow = be32_to_cpu(*shadow); | |
233 | ||
234 | /* find out which gpio groups should be enabled */ | |
235 | groups = of_get_property(pdev->dev.of_node, "lantiq,groups", NULL); | |
236 | if (groups) | |
237 | chip->groups = be32_to_cpu(*groups) & XWAY_STP_GROUP_MASK; | |
238 | else | |
239 | chip->groups = XWAY_STP_GROUP0; | |
240 | chip->gc.ngpio = fls(chip->groups) * 8; | |
241 | ||
242 | /* find out which gpios are controlled by the dsl core */ | |
243 | dsl = of_get_property(pdev->dev.of_node, "lantiq,dsl", NULL); | |
244 | if (dsl) | |
245 | chip->dsl = be32_to_cpu(*dsl) & XWAY_STP_ADSL_MASK; | |
246 | ||
247 | /* find out which gpios are controlled by the phys */ | |
248 | if (of_machine_is_compatible("lantiq,ar9") || | |
249 | of_machine_is_compatible("lantiq,gr9") || | |
250 | of_machine_is_compatible("lantiq,vr9")) { | |
251 | phy = of_get_property(pdev->dev.of_node, "lantiq,phy1", NULL); | |
252 | if (phy) | |
253 | chip->phy1 = be32_to_cpu(*phy) & XWAY_STP_PHY_MASK; | |
254 | phy = of_get_property(pdev->dev.of_node, "lantiq,phy2", NULL); | |
255 | if (phy) | |
256 | chip->phy2 = be32_to_cpu(*phy) & XWAY_STP_PHY_MASK; | |
257 | } | |
258 | ||
259 | /* check which edge trigger we should use, default to a falling edge */ | |
260 | if (!of_find_property(pdev->dev.of_node, "lantiq,rising", NULL)) | |
261 | chip->edge = XWAY_STP_FALLING; | |
262 | ||
263 | clk = clk_get(&pdev->dev, NULL); | |
264 | if (IS_ERR(clk)) { | |
265 | dev_err(&pdev->dev, "Failed to get clock\n"); | |
266 | return PTR_ERR(clk); | |
267 | } | |
268 | clk_enable(clk); | |
269 | ||
270 | ret = xway_stp_hw_init(chip); | |
935c500c | 271 | if (!ret) |
54f30066 JC |
272 | ret = gpiochip_add(&chip->gc); |
273 | ||
274 | if (!ret) | |
275 | dev_info(&pdev->dev, "Init done\n"); | |
935c500c JC |
276 | |
277 | return ret; | |
278 | } | |
279 | ||
54f30066 JC |
280 | static const struct of_device_id xway_stp_match[] = { |
281 | { .compatible = "lantiq,gpio-stp-xway" }, | |
282 | {}, | |
283 | }; | |
284 | MODULE_DEVICE_TABLE(of, xway_stp_match); | |
285 | ||
286 | static struct platform_driver xway_stp_driver = { | |
287 | .probe = xway_stp_probe, | |
935c500c | 288 | .driver = { |
54f30066 | 289 | .name = "gpio-stp-xway", |
935c500c | 290 | .owner = THIS_MODULE, |
54f30066 | 291 | .of_match_table = xway_stp_match, |
935c500c JC |
292 | }, |
293 | }; | |
294 | ||
54f30066 | 295 | int __init xway_stp_init(void) |
935c500c | 296 | { |
54f30066 | 297 | return platform_driver_register(&xway_stp_driver); |
935c500c JC |
298 | } |
299 | ||
54f30066 | 300 | subsys_initcall(xway_stp_init); |