arch/arm/plat-omap/i2c.c

   1 /*
   2  * linux/arch/arm/plat-omap/i2c.c
   3  *
   4  * Helper module for board specific I2C bus registration
   5  *
   6  * Copyright (C) 2007 Nokia Corporation.
   7  *
   8  * Contact: Jarkko Nikula <jhnikula@gmail.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * version 2 as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  22  * 02110-1301 USA
  23  *
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/i2c.h>
  29 #include <linux/i2c-omap.h>
  30 #include <linux/slab.h>
  31 #include <linux/err.h>
  32 #include <linux/clk.h>
  33
  34 #include <mach/irqs.h>
  35 #include <plat/i2c.h>
  36 #include <plat/omap-pm.h>
  37 #include <plat/omap_device.h>
  38
  39 #define OMAP_I2C_SIZE           0x3f
  40 #define OMAP1_I2C_BASE          0xfffb3800
  41 #define OMAP1_INT_I2C           (32 + 4)
  42
  43 static const char name[] = "omap_i2c";
  44
  45 #define I2C_RESOURCE_BUILDER(base, irq)                 \
  46         {                                               \
  47                 .start  = (base),                       \
  48                 .end    = (base) + OMAP_I2C_SIZE,       \
  49                 .flags  = IORESOURCE_MEM,               \
  50         },                                              \
  51         {                                               \
  52                 .start  = (irq),                        \
  53                 .flags  = IORESOURCE_IRQ,               \
  54         },
  55
  56 static struct resource i2c_resources[][2] = {
  57         { I2C_RESOURCE_BUILDER(0, 0) },
  58 };
  59
  60 #define I2C_DEV_BUILDER(bus_id, res, data)              \
  61         {                                               \
  62                 .id     = (bus_id),                     \
  63                 .name   = name,                         \
  64                 .num_resources  = ARRAY_SIZE(res),      \
  65                 .resource       = (res),                \
  66                 .dev            = {                     \
  67                         .platform_data  = (data),       \
  68                 },                                      \
  69         }
  70
  71 #define MAX_OMAP_I2C_HWMOD_NAME_LEN     16
  72 #define OMAP_I2C_MAX_CONTROLLERS 4
  73 static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];
  74 static struct platform_device omap_i2c_devices[] = {
  75         I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_pdata[0]),
  76 };
  77
  78 #define OMAP_I2C_CMDLINE_SETUP  (BIT(31))
  79
  80 static int __init omap_i2c_nr_ports(void)
  81 {
  82         int ports = 0;
  83
  84         if (cpu_class_is_omap1())
  85                 ports = 1;
  86         else if (cpu_is_omap24xx())
  87                 ports = 2;
  88         else if (cpu_is_omap34xx())
  89                 ports = 3;
  90         else if (cpu_is_omap44xx())
  91                 ports = 4;
  92
  93         return ports;
  94 }
  95
  96 static inline int omap1_i2c_add_bus(int bus_id)
  97 {
  98         struct platform_device *pdev;
  99         struct omap_i2c_bus_platform_data *pdata;
 100         struct resource *res;
 101
 102         omap1_i2c_mux_pins(bus_id);
 103
 104         pdev = &omap_i2c_devices[bus_id - 1];
 105         res = pdev->resource;
 106         res[0].start = OMAP1_I2C_BASE;
 107         res[0].end = res[0].start + OMAP_I2C_SIZE;
 108         res[1].start = OMAP1_INT_I2C;
 109         pdata = &i2c_pdata[bus_id - 1];
 110
 111         /* all OMAP1 have IP version 1 register set */
 112         pdata->rev = OMAP_I2C_IP_VERSION_1;
 113
 114         /* all OMAP1 I2C are implemented like this */
 115         pdata->flags = OMAP_I2C_FLAG_NO_FIFO |
 116                        OMAP_I2C_FLAG_SIMPLE_CLOCK |
 117                        OMAP_I2C_FLAG_16BIT_DATA_REG |
 118                        OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK;
 119
 120         /* how the cpu bus is wired up differs for 7xx only */
 121
 122         if (cpu_is_omap7xx())
 123                 pdata->flags |= OMAP_I2C_FLAG_BUS_SHIFT_1;
 124         else
 125                 pdata->flags |= OMAP_I2C_FLAG_BUS_SHIFT_2;
 126
 127         return platform_device_register(pdev);
 128 }
 129
 130
 131 #ifdef CONFIG_ARCH_OMAP2PLUS
 132 /*
 133  * XXX This function is a temporary compatibility wrapper - only
 134  * needed until the I2C driver can be converted to call
 135  * omap_pm_set_max_dev_wakeup_lat() and handle a return code.
 136  */
 137 static void omap_pm_set_max_mpu_wakeup_lat_compat(struct device *dev, long t)
 138 {
 139         omap_pm_set_max_mpu_wakeup_lat(dev, t);
 140 }
 141
 142 static inline int omap2_i2c_add_bus(int bus_id)
 143 {
 144         int l;
 145         struct omap_hwmod *oh;
 146         struct platform_device *pdev;
 147         char oh_name[MAX_OMAP_I2C_HWMOD_NAME_LEN];
 148         struct omap_i2c_bus_platform_data *pdata;
 149         struct omap_i2c_dev_attr *dev_attr;
 150
 151         omap2_i2c_mux_pins(bus_id);
 152
 153         l = snprintf(oh_name, MAX_OMAP_I2C_HWMOD_NAME_LEN, "i2c%d", bus_id);
 154         WARN(l >= MAX_OMAP_I2C_HWMOD_NAME_LEN,
 155                 "String buffer overflow in I2C%d device setup\n", bus_id);
 156         oh = omap_hwmod_lookup(oh_name);
 157         if (!oh) {
 158                         pr_err("Could not look up %s\n", oh_name);
 159                         return -EEXIST;
 160         }
 161
 162         pdata = &i2c_pdata[bus_id - 1];
 163         /*
 164          * pass the hwmod class's CPU-specific knowledge of I2C IP revision in
 165          * use, and functionality implementation flags, up to the OMAP I2C
 166          * driver via platform data
 167          */
 168         pdata->rev = oh->class->rev;
 169
 170         dev_attr = (struct omap_i2c_dev_attr *)oh->dev_attr;
 171         pdata->flags = dev_attr->flags;
 172
 173         /*
 174          * When waiting for completion of a i2c transfer, we need to
 175          * set a wake up latency constraint for the MPU. This is to
 176          * ensure quick enough wakeup from idle, when transfer
 177          * completes.
 178          * Only omap3 has support for constraints
 179          */
 180         if (cpu_is_omap34xx())
 181                 pdata->set_mpu_wkup_lat = omap_pm_set_max_mpu_wakeup_lat_compat;
 182         pdev = omap_device_build(name, bus_id, oh, pdata,
 183                         sizeof(struct omap_i2c_bus_platform_data),
 184                         NULL, 0, 0);
 185         WARN(IS_ERR(pdev), "Could not build omap_device for %s\n", name);
 186
 187         return PTR_RET(pdev);
 188 }
 189 #else
 190 static inline int omap2_i2c_add_bus(int bus_id)
 191 {
 192         return 0;
 193 }
 194 #endif
 195
 196 static int __init omap_i2c_add_bus(int bus_id)
 197 {
 198         if (cpu_class_is_omap1())
 199                 return omap1_i2c_add_bus(bus_id);
 200         else
 201                 return omap2_i2c_add_bus(bus_id);
 202 }
 203
 204 /**
 205  * omap_i2c_bus_setup - Process command line options for the I2C bus speed
 206  * @str: String of options
 207  *
 208  * This function allow to override the default I2C bus speed for given I2C
 209  * bus with a command line option.
 210  *
 211  * Format: i2c_bus=bus_id,clkrate (in kHz)
 212  *
 213  * Returns 1 on success, 0 otherwise.
 214  */
 215 static int __init omap_i2c_bus_setup(char *str)
 216 {
 217         int ports;
 218         int ints[3];
 219
 220         ports = omap_i2c_nr_ports();
 221         get_options(str, 3, ints);
 222         if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
 223                 return 0;
 224         i2c_pdata[ints[1] - 1].clkrate = ints[2];
 225         i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP;
 226
 227         return 1;
 228 }
 229 __setup("i2c_bus=", omap_i2c_bus_setup);
 230
 231 /*
 232  * Register busses defined in command line but that are not registered with
 233  * omap_register_i2c_bus from board initialization code.
 234  */
 235 static int __init omap_register_i2c_bus_cmdline(void)
 236 {
 237         int i, err = 0;
 238
 239         for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++)
 240                 if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
 241                         i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
 242                         err = omap_i2c_add_bus(i + 1);
 243                         if (err)
 244                                 goto out;
 245                 }
 246
 247 out:
 248         return err;
 249 }
 250 subsys_initcall(omap_register_i2c_bus_cmdline);
 251
 252 /**
 253  * omap_register_i2c_bus - register I2C bus with device descriptors
 254  * @bus_id: bus id counting from number 1
 255  * @clkrate: clock rate of the bus in kHz
 256  * @info: pointer into I2C device descriptor table or NULL
 257  * @len: number of descriptors in the table
 258  *
 259  * Returns 0 on success or an error code.
 260  */
 261 int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
 262                           struct i2c_board_info const *info,
 263                           unsigned len)
 264 {
 265         int err;
 266
 267         BUG_ON(bus_id < 1 || bus_id > omap_i2c_nr_ports());
 268
 269         if (info) {
 270                 err = i2c_register_board_info(bus_id, info, len);
 271                 if (err)
 272                         return err;
 273         }
 274
 275         if (!i2c_pdata[bus_id - 1].clkrate)
 276                 i2c_pdata[bus_id - 1].clkrate = clkrate;
 277
 278         i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
 279
 280         return omap_i2c_add_bus(bus_id);
 281 }