libnvdimm/altmap: Track namespace boundaries in altmap
[linux-2.6-block.git] / drivers / gpio / gpio-stp-xway.c
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d2912cb1 1// SPDX-License-Identifier: GPL-2.0-only
935c500c 2/*
935c500c 3 *
baddc7ca 4 * Copyright (C) 2012 John Crispin <john@phrozen.org>
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5 */
6
7#include <linux/slab.h>
8#include <linux/init.h>
54f30066 9#include <linux/module.h>
935c500c 10#include <linux/types.h>
54f30066 11#include <linux/of_platform.h>
935c500c 12#include <linux/mutex.h>
97a48fcd 13#include <linux/gpio/driver.h>
54f30066 14#include <linux/io.h>
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15#include <linux/clk.h>
16#include <linux/err.h>
935c500c 17
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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 (0xf << 23)
45
46/* clock source for automatic update */
47#define XWAY_STP_UPD_FPI BIT(31)
48#define XWAY_STP_UPD_MASK (BIT(31) | BIT(30))
49
50/* let the adsl core drive the 2 LSBs */
51#define XWAY_STP_ADSL_SHIFT 24
52#define XWAY_STP_ADSL_MASK 0x3
53
54/* 2 groups of 3 bits can be driven by the phys */
08b085a0 55#define XWAY_STP_PHY_MASK 0x7
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56#define XWAY_STP_PHY1_SHIFT 27
57#define XWAY_STP_PHY2_SHIFT 15
58
59/* STP has 3 groups of 8 bits */
60#define XWAY_STP_GROUP0 BIT(0)
61#define XWAY_STP_GROUP1 BIT(1)
62#define XWAY_STP_GROUP2 BIT(2)
63#define XWAY_STP_GROUP_MASK (0x7)
64
65/* Edge configuration bits */
66#define XWAY_STP_FALLING BIT(26)
67#define XWAY_STP_EDGE_MASK BIT(26)
68
69#define xway_stp_r32(m, reg) __raw_readl(m + reg)
70#define xway_stp_w32(m, val, reg) __raw_writel(val, m + reg)
71#define xway_stp_w32_mask(m, clear, set, reg) \
c0ec7012 72 xway_stp_w32(m, (xway_stp_r32(m, reg) & ~(clear)) | (set), reg)
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73
74struct xway_stp {
75 struct gpio_chip gc;
76 void __iomem *virt;
77 u32 edge; /* rising or falling edge triggered shift register */
c9e854cf 78 u32 shadow; /* shadow the shift registers state */
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79 u8 groups; /* we can drive 1-3 groups of 8bit each */
80 u8 dsl; /* the 2 LSBs can be driven by the dsl core */
81 u8 phy1; /* 3 bits can be driven by phy1 */
82 u8 phy2; /* 3 bits can be driven by phy2 */
83 u8 reserved; /* mask out the hw driven bits in gpio_request */
84};
85
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86/**
87 * xway_stp_get() - gpio_chip->get - get gpios.
88 * @gc: Pointer to gpio_chip device structure.
89 * @gpio: GPIO signal number.
90 *
91 * Gets the shadow value.
92 */
93static int xway_stp_get(struct gpio_chip *gc, unsigned int gpio)
94{
95 struct xway_stp *chip = gpiochip_get_data(gc);
96
97 return (xway_stp_r32(chip->virt, XWAY_STP_CPU0) & BIT(gpio));
98}
99
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100/**
101 * xway_stp_set() - gpio_chip->set - set gpios.
102 * @gc: Pointer to gpio_chip device structure.
103 * @gpio: GPIO signal number.
104 * @val: Value to be written to specified signal.
105 *
106 * Set the shadow value and call ltq_ebu_apply.
107 */
108static void xway_stp_set(struct gpio_chip *gc, unsigned gpio, int val)
935c500c 109{
c63b30b0 110 struct xway_stp *chip = gpiochip_get_data(gc);
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111
112 if (val)
113 chip->shadow |= BIT(gpio);
935c500c 114 else
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115 chip->shadow &= ~BIT(gpio);
116 xway_stp_w32(chip->virt, chip->shadow, XWAY_STP_CPU0);
117 xway_stp_w32_mask(chip->virt, 0, XWAY_STP_CON_SWU, XWAY_STP_CON0);
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118}
119
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120/**
121 * xway_stp_dir_out() - gpio_chip->dir_out - set gpio direction.
122 * @gc: Pointer to gpio_chip device structure.
123 * @gpio: GPIO signal number.
124 * @val: Value to be written to specified signal.
125 *
126 * Same as xway_stp_set, always returns 0.
127 */
128static int xway_stp_dir_out(struct gpio_chip *gc, unsigned gpio, int val)
935c500c 129{
54f30066 130 xway_stp_set(gc, gpio, val);
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131
132 return 0;
133}
134
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135/**
136 * xway_stp_request() - gpio_chip->request
137 * @gc: Pointer to gpio_chip device structure.
138 * @gpio: GPIO signal number.
139 *
140 * We mask out the HW driven pins
141 */
142static int xway_stp_request(struct gpio_chip *gc, unsigned gpio)
143{
c63b30b0 144 struct xway_stp *chip = gpiochip_get_data(gc);
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145
146 if ((gpio < 8) && (chip->reserved & BIT(gpio))) {
58383c78 147 dev_err(gc->parent, "GPIO %d is driven by hardware\n", gpio);
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148 return -ENODEV;
149 }
935c500c 150
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151 return 0;
152}
153
154/**
155 * xway_stp_hw_init() - Configure the STP unit and enable the clock gate
8a7b1797 156 * @chip: Pointer to the xway_stp chip structure
54f30066 157 */
8a7b1797 158static void xway_stp_hw_init(struct xway_stp *chip)
935c500c 159{
935c500c 160 /* sane defaults */
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161 xway_stp_w32(chip->virt, 0, XWAY_STP_AR);
162 xway_stp_w32(chip->virt, 0, XWAY_STP_CPU0);
163 xway_stp_w32(chip->virt, 0, XWAY_STP_CPU1);
164 xway_stp_w32(chip->virt, XWAY_STP_CON_SWU, XWAY_STP_CON0);
165 xway_stp_w32(chip->virt, 0, XWAY_STP_CON1);
935c500c 166
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167 /* apply edge trigger settings for the shift register */
168 xway_stp_w32_mask(chip->virt, XWAY_STP_EDGE_MASK,
169 chip->edge, XWAY_STP_CON0);
935c500c 170
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171 /* apply led group settings */
172 xway_stp_w32_mask(chip->virt, XWAY_STP_GROUP_MASK,
173 chip->groups, XWAY_STP_CON1);
935c500c 174
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175 /* tell the hardware which pins are controlled by the dsl modem */
176 xway_stp_w32_mask(chip->virt,
177 XWAY_STP_ADSL_MASK << XWAY_STP_ADSL_SHIFT,
178 chip->dsl << XWAY_STP_ADSL_SHIFT,
179 XWAY_STP_CON0);
935c500c 180
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181 /* tell the hardware which pins are controlled by the phys */
182 xway_stp_w32_mask(chip->virt,
183 XWAY_STP_PHY_MASK << XWAY_STP_PHY1_SHIFT,
184 chip->phy1 << XWAY_STP_PHY1_SHIFT,
185 XWAY_STP_CON0);
186 xway_stp_w32_mask(chip->virt,
187 XWAY_STP_PHY_MASK << XWAY_STP_PHY2_SHIFT,
188 chip->phy2 << XWAY_STP_PHY2_SHIFT,
189 XWAY_STP_CON1);
935c500c 190
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191 /* mask out the hw driven bits in gpio_request */
192 chip->reserved = (chip->phy2 << 5) | (chip->phy1 << 2) | chip->dsl;
193
194 /*
195 * if we have pins that are driven by hw, we need to tell the stp what
196 * clock to use as a timer.
935c500c 197 */
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198 if (chip->reserved)
199 xway_stp_w32_mask(chip->virt, XWAY_STP_UPD_MASK,
200 XWAY_STP_UPD_FPI, XWAY_STP_CON1);
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201}
202
3836309d 203static int xway_stp_probe(struct platform_device *pdev)
935c500c 204{
50f09073 205 u32 shadow, groups, dsl, phy;
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206 struct xway_stp *chip;
207 struct clk *clk;
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208 int ret = 0;
209
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210 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
211 if (!chip)
212 return -ENOMEM;
213
6ba7c53b 214 chip->virt = devm_platform_ioremap_resource(pdev, 0);
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215 if (IS_ERR(chip->virt))
216 return PTR_ERR(chip->virt);
8ab2a6d2 217
58383c78 218 chip->gc.parent = &pdev->dev;
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219 chip->gc.label = "stp-xway";
220 chip->gc.direction_output = xway_stp_dir_out;
5b9b2b52 221 chip->gc.get = xway_stp_get;
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222 chip->gc.set = xway_stp_set;
223 chip->gc.request = xway_stp_request;
224 chip->gc.base = -1;
225 chip->gc.owner = THIS_MODULE;
226
227 /* store the shadow value if one was passed by the devicetree */
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228 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,shadow", &shadow))
229 chip->shadow = shadow;
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230
231 /* find out which gpio groups should be enabled */
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232 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,groups", &groups))
233 chip->groups = groups & XWAY_STP_GROUP_MASK;
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234 else
235 chip->groups = XWAY_STP_GROUP0;
236 chip->gc.ngpio = fls(chip->groups) * 8;
237
238 /* find out which gpios are controlled by the dsl core */
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239 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,dsl", &dsl))
240 chip->dsl = dsl & XWAY_STP_ADSL_MASK;
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241
242 /* find out which gpios are controlled by the phys */
243 if (of_machine_is_compatible("lantiq,ar9") ||
244 of_machine_is_compatible("lantiq,gr9") ||
245 of_machine_is_compatible("lantiq,vr9")) {
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246 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy1", &phy))
247 chip->phy1 = phy & XWAY_STP_PHY_MASK;
248 if (!of_property_read_u32(pdev->dev.of_node, "lantiq,phy2", &phy))
249 chip->phy2 = phy & XWAY_STP_PHY_MASK;
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250 }
251
252 /* check which edge trigger we should use, default to a falling edge */
253 if (!of_find_property(pdev->dev.of_node, "lantiq,rising", NULL))
254 chip->edge = XWAY_STP_FALLING;
255
bd791c48 256 clk = devm_clk_get(&pdev->dev, NULL);
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257 if (IS_ERR(clk)) {
258 dev_err(&pdev->dev, "Failed to get clock\n");
259 return PTR_ERR(clk);
260 }
54f30066 261
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262 ret = clk_prepare_enable(clk);
263 if (ret)
264 return ret;
54f30066 265
8a7b1797 266 xway_stp_hw_init(chip);
935c500c 267
8a7b1797 268 ret = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
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269 if (ret) {
270 clk_disable_unprepare(clk);
8a7b1797 271 return ret;
bd791c48 272 }
935c500c 273
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274 dev_info(&pdev->dev, "Init done\n");
275
276 return 0;
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277}
278
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279static const struct of_device_id xway_stp_match[] = {
280 { .compatible = "lantiq,gpio-stp-xway" },
281 {},
282};
283MODULE_DEVICE_TABLE(of, xway_stp_match);
284
285static struct platform_driver xway_stp_driver = {
286 .probe = xway_stp_probe,
935c500c 287 .driver = {
54f30066 288 .name = "gpio-stp-xway",
54f30066 289 .of_match_table = xway_stp_match,
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290 },
291};
292
afdadc06 293static int __init xway_stp_init(void)
935c500c 294{
54f30066 295 return platform_driver_register(&xway_stp_driver);
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296}
297
54f30066 298subsys_initcall(xway_stp_init);