target/linux/ramips/patches-3.14/0052-i2c-MIPS-adds-ralink-I2C-driver.patch

   1 From 225f36695bb07dad9510f9affd79e63f1a44a195 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Sun, 27 Jul 2014 09:52:56 +0100
   4 Subject: [PATCH 52/57] i2c: MIPS: adds ralink I2C driver
   5
   6 Signed-off-by: John Crispin <blogic@openwrt.org>
   7 ---
   8  .../devicetree/bindings/i2c/i2c-ralink.txt         |   27 ++
   9  drivers/i2c/busses/Kconfig                         |    4 +
  10  drivers/i2c/busses/Makefile                        |    1 +
  11  drivers/i2c/busses/i2c-ralink.c                    |  274 ++++++++++++++++++++
  12  4 files changed, 306 insertions(+)
  13  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-ralink.txt
  14  create mode 100644 drivers/i2c/busses/i2c-ralink.c
  15
  16 Index: linux-3.14.16/Documentation/devicetree/bindings/i2c/i2c-ralink.txt
  17 ===================================================================
  18 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
  19 +++ linux-3.14.16/Documentation/devicetree/bindings/i2c/i2c-ralink.txt  2014-08-24 16:03:20.586671002 +0200
  20 @@ -0,0 +1,27 @@
  21 +I2C for Ralink platforms
  22 +
  23 +Required properties :
  24 +- compatible : Must be "link,rt3052-i2c"
  25 +- reg: physical base address of the controller and length of memory mapped
  26 +     region.
  27 +- #address-cells = <1>;
  28 +- #size-cells = <0>;
  29 +
  30 +Optional properties:
  31 +- Child nodes conforming to i2c bus binding
  32 +
  33 +Example :
  34 +
  35 +palmbus@10000000 {
  36 +       i2c@900 {
  37 +               compatible = "link,rt3052-i2c";
  38 +               reg = <0x900 0x100>;
  39 +               #address-cells = <1>;
  40 +               #size-cells = <0>;
  41 +
  42 +               hwmon@4b {
  43 +                       compatible = "national,lm92";
  44 +                       reg = <0x4b>;
  45 +               };
  46 +       };
  47 +};
  48 Index: linux-3.14.16/drivers/i2c/busses/Kconfig
  49 ===================================================================
  50 --- linux-3.14.16.orig/drivers/i2c/busses/Kconfig       2014-08-08 01:50:59.000000000 +0200
  51 +++ linux-3.14.16/drivers/i2c/busses/Kconfig    2014-08-24 16:03:20.586671002 +0200
  52 @@ -659,6 +659,10 @@
  53           This driver can also be built as a module.  If so, the module
  54           will be called i2c-riic.
  55
  56 +config I2C_RALINK
  57 +       tristate "Ralink I2C Controller"
  58 +       select OF_I2C
  59 +
  60  config HAVE_S3C2410_I2C
  61         bool
  62         help
  63 Index: linux-3.14.16/drivers/i2c/busses/Makefile
  64 ===================================================================
  65 --- linux-3.14.16.orig/drivers/i2c/busses/Makefile      2014-08-08 01:50:59.000000000 +0200
  66 +++ linux-3.14.16/drivers/i2c/busses/Makefile   2014-08-24 16:03:20.586671002 +0200
  67 @@ -63,6 +63,7 @@
  68  obj-$(CONFIG_I2C_PUV3)         += i2c-puv3.o
  69  obj-$(CONFIG_I2C_PXA)          += i2c-pxa.o
  70  obj-$(CONFIG_I2C_PXA_PCI)      += i2c-pxa-pci.o
  71 +obj-$(CONFIG_I2C_RALINK)       += i2c-ralink.o
  72  obj-$(CONFIG_I2C_RIIC)         += i2c-riic.o
  73  obj-$(CONFIG_I2C_S3C2410)      += i2c-s3c2410.o
  74  obj-$(CONFIG_I2C_S6000)                += i2c-s6000.o
  75 Index: linux-3.14.16/drivers/i2c/busses/i2c-ralink.c
  76 ===================================================================
  77 --- /dev/null   1970-01-01 00:00:00.000000000 +0000
  78 +++ linux-3.14.16/drivers/i2c/busses/i2c-ralink.c       2014-08-27 23:07:01.318731261 +0200
  79 @@ -0,0 +1,271 @@
  80 +/*
  81 + * drivers/i2c/busses/i2c-ralink.c
  82 + *
  83 + * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com>
  84 + *
  85 + * This software is licensed under the terms of the GNU General Public
  86 + * License version 2, as published by the Free Software Foundation, and
  87 + * may be copied, distributed, and modified under those terms.
  88 + *
  89 + * This program is distributed in the hope that it will be useful,
  90 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
  91 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  92 + * GNU General Public License for more details.
  93 + *
  94 + */
  95 +
  96 +#include <linux/interrupt.h>
  97 +#include <linux/kernel.h>
  98 +#include <linux/module.h>
  99 +#include <linux/reset.h>
 100 +#include <linux/delay.h>
 101 +#include <linux/slab.h>
 102 +#include <linux/init.h>
 103 +#include <linux/errno.h>
 104 +#include <linux/platform_device.h>
 105 +#include <linux/i2c.h>
 106 +#include <linux/io.h>
 107 +#include <linux/err.h>
 108 +
 109 +#include <asm/mach-ralink/ralink_regs.h>
 110 +
 111 +#define REG_CONFIG_REG         0x00
 112 +#define REG_CLKDIV_REG         0x04
 113 +#define REG_DEVADDR_REG                0x08
 114 +#define REG_ADDR_REG           0x0C
 115 +#define REG_DATAOUT_REG                0x10
 116 +#define REG_DATAIN_REG         0x14
 117 +#define REG_STATUS_REG         0x18
 118 +#define REG_STARTXFR_REG       0x1C
 119 +#define REG_BYTECNT_REG                0x20
 120 +
 121 +#define I2C_STARTERR           BIT(4)
 122 +#define I2C_ACKERR             BIT(3)
 123 +#define I2C_DATARDY            BIT(2)
 124 +#define I2C_SDOEMPTY           BIT(1)
 125 +#define I2C_BUSY               BIT(0)
 126 +
 127 +#define I2C_DEVADLEN_7         (6 << 2)
 128 +#define I2C_ADDRDIS            BIT(1)
 129 +
 130 +#define I2C_RETRY              0x400
 131 +
 132 +#define CLKDIV_VALUE           200 // clock rate is 40M, 40M / (200*2) = 100k (standard i2c bus rate).
 133 +//#define CLKDIV_VALUE         50 // clock rate is 40M, 40M / (50*2) = 400k (fast i2c bus rate).
 134 +
 135 +#define READ_CMD               0x01
 136 +#define WRITE_CMD              0x00
 137 +#define READ_BLOCK              64
 138 +
 139 +static void __iomem *membase;
 140 +static struct i2c_adapter *adapter;
 141 +
 142 +static void rt_i2c_w32(u32 val, unsigned reg)
 143 +{
 144 +       iowrite32(val, membase + reg);
 145 +}
 146 +
 147 +static u32 rt_i2c_r32(unsigned reg)
 148 +{
 149 +       return ioread32(membase + reg);
 150 +}
 151 +
 152 +static inline int rt_i2c_wait_rx_done(void)
 153 +{
 154 +       int retries = I2C_RETRY;
 155 +
 156 +       do {
 157 +               if (!retries--)
 158 +                       break;
 159 +       } while(!(rt_i2c_r32(REG_STATUS_REG) & I2C_DATARDY));
 160 +
 161 +       return (retries < 0);
 162 +}
 163 +
 164 +static inline int rt_i2c_wait_idle(void)
 165 +{
 166 +       int retries = I2C_RETRY;
 167 +
 168 +       do {
 169 +               if (!retries--)
 170 +                       break;
 171 +       } while(rt_i2c_r32(REG_STATUS_REG) & I2C_BUSY);
 172 +
 173 +       return (retries < 0);
 174 +}
 175 +
 176 +static inline int rt_i2c_wait_tx_done(void)
 177 +{
 178 +       int retries = I2C_RETRY;
 179 +
 180 +       do {
 181 +               if (!retries--)
 182 +                       break;
 183 +       } while(!(rt_i2c_r32(REG_STATUS_REG) & I2C_SDOEMPTY));
 184 +
 185 +       return (retries < 0);
 186 +}
 187 +
 188 +static int rt_i2c_handle_msg(struct i2c_adapter *a, struct i2c_msg* msg)
 189 +{
 190 +       int i = 0, j = 0, pos = 0;
 191 +       int nblock = msg->len / READ_BLOCK;
 192 +        int rem = msg->len % READ_BLOCK;
 193 +
 194 +       if (msg->flags & I2C_M_TEN) {
 195 +               printk("10 bits addr not supported\n");
 196 +               return -EINVAL;
 197 +       }
 198 +
 199 +       if (msg->flags & I2C_M_RD) {
 200 +               for (i = 0; i < nblock; i++) {
 201 +                       rt_i2c_wait_idle();
 202 +                       rt_i2c_w32(READ_BLOCK - 1, REG_BYTECNT_REG);
 203 +                       rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
 204 +                       for (j = 0; j < READ_BLOCK; j++) {
 205 +                               if (rt_i2c_wait_rx_done())
 206 +                                       return -1;
 207 +                               msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
 208 +                       }
 209 +               }
 210 +
 211 +               rt_i2c_wait_idle();
 212 +               rt_i2c_w32(rem - 1, REG_BYTECNT_REG);
 213 +               rt_i2c_w32(READ_CMD, REG_STARTXFR_REG);
 214 +               for (i = 0; i < rem; i++) {
 215 +                       if (rt_i2c_wait_rx_done())
 216 +                               return -1;
 217 +                       msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG);
 218 +               }
 219 +       } else {
 220 +               rt_i2c_wait_idle();
 221 +               rt_i2c_w32(msg->len - 1, REG_BYTECNT_REG);
 222 +               for (i = 0; i < msg->len; i++) {
 223 +                       rt_i2c_w32(msg->buf[i], REG_DATAOUT_REG);
 224 +                       rt_i2c_w32(WRITE_CMD, REG_STARTXFR_REG);
 225 +                       if (rt_i2c_wait_tx_done())
 226 +                               return -1;
 227 +               }
 228 +       }
 229 +
 230 +       return 0;
 231 +}
 232 +
 233 +static int rt_i2c_master_xfer(struct i2c_adapter *a, struct i2c_msg *m, int n)
 234 +{
 235 +       int i = 0;
 236 +       int ret = 0;
 237 +
 238 +       if (rt_i2c_wait_idle()) {
 239 +               printk("i2c transfer failed\n");
 240 +               return 0;
 241 +       }
 242 +
 243 +       device_reset(a->dev.parent);
 244 +
 245 +       rt_i2c_w32(m->addr, REG_DEVADDR_REG);
 246 +       rt_i2c_w32(I2C_DEVADLEN_7 | I2C_ADDRDIS, REG_CONFIG_REG);
 247 +       rt_i2c_w32(CLKDIV_VALUE, REG_CLKDIV_REG);
 248 +
 249 +       for (i = 0; i < n && !ret; i++)
 250 +               ret = rt_i2c_handle_msg(a, &m[i]);
 251 +
 252 +       if (ret) {
 253 +               printk("i2c transfer failed\n");
 254 +               return 0;
 255 +       }
 256 +
 257 +       return n;
 258 +}
 259 +
 260 +static u32 rt_i2c_func(struct i2c_adapter *a)
 261 +{
 262 +       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 263 +}
 264 +
 265 +static const struct i2c_algorithm rt_i2c_algo = {
 266 +       .master_xfer    = rt_i2c_master_xfer,
 267 +       .functionality  = rt_i2c_func,
 268 +};
 269 +
 270 +static int rt_i2c_probe(struct platform_device *pdev)
 271 +{
 272 +       struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 273 +       int ret;
 274 +
 275 +       if (!res) {
 276 +               dev_err(&pdev->dev, "no memory resource found\n");
 277 +               return -ENODEV;
 278 +       }
 279 +
 280 +       adapter = devm_kzalloc(&pdev->dev, sizeof(struct i2c_adapter), GFP_KERNEL);
 281 +       if (!adapter) {
 282 +               dev_err(&pdev->dev, "failed to allocate i2c_adapter\n");
 283 +               return -ENOMEM;
 284 +       }
 285 +
 286 +       membase = devm_request_and_ioremap(&pdev->dev, res);
 287 +       if (IS_ERR(membase))
 288 +               return PTR_ERR(membase);
 289 +
 290 +       strlcpy(adapter->name, dev_name(&pdev->dev), sizeof(adapter->name));
 291 +       adapter->owner = THIS_MODULE;
 292 +       adapter->nr = pdev->id;
 293 +       adapter->timeout = HZ;
 294 +       adapter->algo = &rt_i2c_algo;
 295 +       adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 296 +       adapter->dev.parent = &pdev->dev;
 297 +       adapter->dev.of_node = pdev->dev.of_node;
 298 +
 299 +       ret = i2c_add_numbered_adapter(adapter);
 300 +       if (ret)
 301 +               return ret;
 302 +
 303 +       platform_set_drvdata(pdev, adapter);
 304 +
 305 +       dev_info(&pdev->dev, "loaded\n");
 306 +
 307 +       return 0;
 308 +}
 309 +
 310 +static int rt_i2c_remove(struct platform_device *pdev)
 311 +{
 312 +       platform_set_drvdata(pdev, NULL);
 313 +
 314 +       return 0;
 315 +}
 316 +
 317 +static const struct of_device_id i2c_rt_dt_ids[] = {
 318 +       { .compatible = "ralink,rt2880-i2c", },
 319 +       { /* sentinel */ }
 320 +};
 321 +
 322 +MODULE_DEVICE_TABLE(of, i2c_rt_dt_ids);
 323 +
 324 +static struct platform_driver rt_i2c_driver = {
 325 +       .probe          = rt_i2c_probe,
 326 +       .remove         = rt_i2c_remove,
 327 +       .driver         = {
 328 +               .owner  = THIS_MODULE,
 329 +               .name   = "i2c-ralink",
 330 +               .of_match_table = i2c_rt_dt_ids,
 331 +       },
 332 +};
 333 +
 334 +static int __init i2c_rt_init (void)
 335 +{
 336 +       return platform_driver_register(&rt_i2c_driver);
 337 +}
 338 +subsys_initcall(i2c_rt_init);
 339 +
 340 +static void __exit i2c_rt_exit (void)
 341 +{
 342 +       platform_driver_unregister(&rt_i2c_driver);
 343 +}
 344 +
 345 +module_exit (i2c_rt_exit);
 346 +
 347 +MODULE_AUTHOR("Steven Liu <steven_liu@mediatek.com>");
 348 +MODULE_DESCRIPTION("Ralink I2c host driver");
 349 +MODULE_LICENSE("GPL");
 350 +MODULE_ALIAS("platform:Ralink-I2C");