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 * 6 * Copyright (C) 2012 John Crispin <blogic@openwrt.org> 7 * 8 */ 9 10 #include <linux/slab.h> 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/types.h> 14 #include <linux/of_platform.h> 15 #include <linux/mutex.h> 16 #include <linux/gpio.h> 17 #include <linux/io.h> 18 #include <linux/of_gpio.h> 19 #include <linux/clk.h> 20 #include <linux/err.h> 21 22 #include <lantiq_soc.h> 23 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 */ 85 u32 shadow; /* shadow the shift registers state */ 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) 102 { 103 struct xway_stp *chip = 104 container_of(gc, struct xway_stp, gc); 105 106 if (val) 107 chip->shadow |= BIT(gpio); 108 else 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); 112 } 113 114 /** 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) 123 { 124 xway_stp_set(gc, gpio, val); 125 126 return 0; 127 } 128 129 /** 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 } 145 146 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) 154 { 155 /* sane defaults */ 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); 161 162 /* 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); 165 166 /* apply led group settings */ 167 xway_stp_w32_mask(chip->virt, XWAY_STP_GROUP_MASK, 168 chip->groups, XWAY_STP_CON1); 169 170 /* 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); 175 176 /* 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); 185 186 /* 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. 192 */ 193 if (chip->reserved) 194 xway_stp_w32_mask(chip->virt, XWAY_STP_UPD_MASK, 195 XWAY_STP_UPD_FPI, XWAY_STP_CON1); 196 197 return 0; 198 } 199 200 static int xway_stp_probe(struct platform_device *pdev) 201 { 202 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 203 const __be32 *shadow, *groups, *dsl, *phy; 204 struct xway_stp *chip; 205 struct clk *clk; 206 int ret = 0; 207 208 if (!res) { 209 dev_err(&pdev->dev, "failed to request STP resource\n"); 210 return -ENOENT; 211 } 212 213 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); 214 if (!chip) 215 return -ENOMEM; 216 217 chip->virt = devm_ioremap_resource(&pdev->dev, res); 218 if (IS_ERR(chip->virt)) 219 return PTR_ERR(chip->virt); 220 221 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); 271 if (!ret) 272 ret = gpiochip_add(&chip->gc); 273 274 if (!ret) 275 dev_info(&pdev->dev, "Init done\n"); 276 277 return ret; 278 } 279 280 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, 288 .driver = { 289 .name = "gpio-stp-xway", 290 .owner = THIS_MODULE, 291 .of_match_table = xway_stp_match, 292 }, 293 }; 294 295 int __init xway_stp_init(void) 296 { 297 return platform_driver_register(&xway_stp_driver); 298 } 299 300 subsys_initcall(xway_stp_init); 301