drivers/mfd/stw481x.c

   1 /*
   2  * Core driver for STw4810/STw4811
   3  *
   4  * Copyright (C) 2013 ST-Ericsson SA
   5  * Written on behalf of Linaro for ST-Ericsson
   6  *
   7  * Author: Linus Walleij <linus.walleij@linaro.org>
   8  *
   9  * License terms: GNU General Public License (GPL) version 2
  10  */
  11
  12 #include <linux/err.h>
  13 #include <linux/i2c.h>
  14 #include <linux/init.h>
  15 #include <linux/mfd/core.h>
  16 #include <linux/mfd/stw481x.h>
  17 #include <linux/module.h>
  18 #include <linux/regmap.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/slab.h>
  21
  22 /*
  23  * This driver can only access the non-USB portions of STw4811, the register
  24  * range 0x00-0x10 dealing with USB is bound to the two special I2C pins used
  25  * for USB control.
  26  */
  27
  28 /* Registers inside the power control address space */
  29 #define STW_PC_VCORE_SEL        0x05U
  30 #define STW_PC_VAUX_SEL         0x06U
  31 #define STW_PC_VPLL_SEL         0x07U
  32
  33 /**
  34  * stw481x_get_pctl_reg() - get a power control register
  35  * @stw481x: handle to the stw481x chip
  36  * @reg: power control register to fetch
  37  *
  38  * The power control registers is a set of one-time-programmable registers
  39  * in its own register space, accessed by writing addess bits to these
  40  * two registers: bits 7,6,5 of PCTL_REG_LO corresponds to the 3 LSBs of
  41  * the address and bits 8,9 of PCTL_REG_HI corresponds to the 2 MSBs of
  42  * the address, forming an address space of 5 bits, i.e. 32 registers
  43  * 0x00 ... 0x1f can be obtained.
  44  */
  45 static int stw481x_get_pctl_reg(struct stw481x *stw481x, u8 reg)
  46 {
  47         u8 msb = (reg >> 3) & 0x03;
  48         u8 lsb = (reg << 5) & 0xe0;
  49         unsigned int val;
  50         u8 vrfy;
  51         int ret;
  52
  53         ret = regmap_write(stw481x->map, STW_PCTL_REG_HI, msb);
  54         if (ret)
  55                 return ret;
  56         ret = regmap_write(stw481x->map, STW_PCTL_REG_LO, lsb);
  57         if (ret)
  58                 return ret;
  59         ret = regmap_read(stw481x->map, STW_PCTL_REG_HI, &val);
  60         if (ret)
  61                 return ret;
  62         vrfy = (val & 0x03) << 3;
  63         ret = regmap_read(stw481x->map, STW_PCTL_REG_LO, &val);
  64         if (ret)
  65                 return ret;
  66         vrfy |= ((val >> 5) & 0x07);
  67         if (vrfy != reg)
  68                 return -EIO;
  69         return (val >> 1) & 0x0f;
  70 }
  71
  72 static int stw481x_startup(struct stw481x *stw481x)
  73 {
  74         /* Voltages multiplied by 100 */
  75         u8 vcore_val[] = { 100, 105, 110, 115, 120, 122, 124, 126, 128,
  76                            130, 132, 134, 136, 138, 140, 145 };
  77         u8 vpll_val[] = { 105, 120, 130, 180 };
  78         u8 vaux_val[] = { 15, 18, 25, 28 };
  79         u8 vcore;
  80         u8 vcore_slp;
  81         u8 vpll;
  82         u8 vaux;
  83         bool vaux_en;
  84         bool it_warn;
  85         int ret;
  86         unsigned int val;
  87
  88         ret = regmap_read(stw481x->map, STW_CONF1, &val);
  89         if (ret)
  90                 return ret;
  91         vaux_en = !!(val & STW_CONF1_PDN_VAUX);
  92         it_warn = !!(val & STW_CONF1_IT_WARN);
  93
  94         dev_info(&stw481x->client->dev, "voltages %s\n",
  95                 (val & STW_CONF1_V_MONITORING) ? "OK" : "LOW");
  96         dev_info(&stw481x->client->dev, "MMC level shifter %s\n",
  97                 (val & STW_CONF1_MMC_LS_STATUS) ? "high impedance" : "ON");
  98         dev_info(&stw481x->client->dev, "VMMC: %s\n",
  99                 (val & STW_CONF1_PDN_VMMC) ? "ON" : "disabled");
 100
 101         dev_info(&stw481x->client->dev, "STw481x power control registers:\n");
 102
 103         ret = stw481x_get_pctl_reg(stw481x, STW_PC_VCORE_SEL);
 104         if (ret < 0)
 105                 return ret;
 106         vcore = ret & 0x0f;
 107
 108         ret = stw481x_get_pctl_reg(stw481x, STW_PC_VAUX_SEL);
 109         if (ret < 0)
 110                 return ret;
 111         vaux = (ret >> 2) & 3;
 112         vpll = (ret >> 4) & 1; /* Save bit 4 */
 113
 114         ret = stw481x_get_pctl_reg(stw481x, STW_PC_VPLL_SEL);
 115         if (ret < 0)
 116                 return ret;
 117         vpll |= (ret >> 1) & 2;
 118
 119         dev_info(&stw481x->client->dev, "VCORE: %u.%uV %s\n",
 120                 vcore_val[vcore] / 100, vcore_val[vcore] % 100,
 121                 (ret & 4) ? "ON" : "OFF");
 122
 123         dev_info(&stw481x->client->dev, "VPLL:  %u.%uV %s\n",
 124                 vpll_val[vpll] / 100, vpll_val[vpll] % 100,
 125                 (ret & 0x10) ? "ON" : "OFF");
 126
 127         dev_info(&stw481x->client->dev, "VAUX:  %u.%uV %s\n",
 128                 vaux_val[vaux] / 10, vaux_val[vaux] % 10,
 129                 vaux_en ? "ON" : "OFF");
 130
 131         ret = regmap_read(stw481x->map, STW_CONF2, &val);
 132         if (ret)
 133                 return ret;
 134
 135         dev_info(&stw481x->client->dev, "TWARN: %s threshold, %s\n",
 136                 it_warn ? "below" : "above",
 137                 (val & STW_CONF2_MASK_TWARN) ?
 138                  "enabled" : "mask through VDDOK");
 139         dev_info(&stw481x->client->dev, "VMMC: %s\n",
 140                 (val & STW_CONF2_VMMC_EXT) ? "internal" : "external");
 141         dev_info(&stw481x->client->dev, "IT WAKE UP: %s\n",
 142                 (val & STW_CONF2_MASK_IT_WAKE_UP) ? "enabled" : "masked");
 143         dev_info(&stw481x->client->dev, "GPO1: %s\n",
 144                 (val & STW_CONF2_GPO1) ? "low" : "high impedance");
 145         dev_info(&stw481x->client->dev, "GPO2: %s\n",
 146                 (val & STW_CONF2_GPO2) ? "low" : "high impedance");
 147
 148         ret = regmap_read(stw481x->map, STW_VCORE_SLEEP, &val);
 149         if (ret)
 150                 return ret;
 151         vcore_slp = val & 0x0f;
 152         dev_info(&stw481x->client->dev, "VCORE SLEEP: %u.%uV\n",
 153                 vcore_val[vcore_slp] / 100, vcore_val[vcore_slp] % 100);
 154
 155         return 0;
 156 }
 157
 158 /*
 159  * MFD cells - we have one cell which is selected operation
 160  * mode, and we always have a GPIO cell.
 161  */
 162 static struct mfd_cell stw481x_cells[] = {
 163         {
 164                 .of_compatible = "st,stw481x-vmmc",
 165                 .name = "stw481x-vmmc-regulator",
 166                 .id = -1,
 167         },
 168 };
 169
 170 const struct regmap_config stw481x_regmap_config = {
 171         .reg_bits = 8,
 172         .val_bits = 8,
 173 };
 174
 175 static int stw481x_probe(struct i2c_client *client,
 176                          const struct i2c_device_id *id)
 177 {
 178         struct stw481x                  *stw481x;
 179         int ret;
 180         int i;
 181
 182         stw481x = devm_kzalloc(&client->dev, sizeof(*stw481x), GFP_KERNEL);
 183         if (!stw481x)
 184                 return -ENOMEM;
 185
 186         i2c_set_clientdata(client, stw481x);
 187         stw481x->client = client;
 188         stw481x->map = devm_regmap_init_i2c(client, &stw481x_regmap_config);
 189
 190         ret = stw481x_startup(stw481x);
 191         if (ret) {
 192                 dev_err(&client->dev, "chip initialization failed\n");
 193                 return ret;
 194         }
 195
 196         /* Set up and register the platform devices. */
 197         for (i = 0; i < ARRAY_SIZE(stw481x_cells); i++) {
 198                 /* One state holder for all drivers, this is simple */
 199                 stw481x_cells[i].platform_data = stw481x;
 200                 stw481x_cells[i].pdata_size = sizeof(*stw481x);
 201         }
 202
 203         ret = mfd_add_devices(&client->dev, 0, stw481x_cells,
 204                         ARRAY_SIZE(stw481x_cells), NULL, 0, NULL);
 205         if (ret)
 206                 return ret;
 207
 208         dev_info(&client->dev, "initialized STw481x device\n");
 209
 210         return ret;
 211 }
 212
 213 static int stw481x_remove(struct i2c_client *client)
 214 {
 215         mfd_remove_devices(&client->dev);
 216         return 0;
 217 }
 218
 219 /*
 220  * This ID table is completely unused, as this is a pure
 221  * device-tree probed driver, but it has to be here due to
 222  * the structure of the I2C core.
 223  */
 224 static const struct i2c_device_id stw481x_id[] = {
 225         { "stw481x", 0 },
 226         { },
 227 };
 228
 229 static const struct of_device_id stw481x_match[] = {
 230         { .compatible = "st,stw4810", },
 231         { .compatible = "st,stw4811", },
 232         { },
 233 };
 234 MODULE_DEVICE_TABLE(of, stw481x_match);
 235
 236 static struct i2c_driver stw481x_driver = {
 237         .driver = {
 238                 .name   = "stw481x",
 239                 .of_match_table = stw481x_match,
 240         },
 241         .probe          = stw481x_probe,
 242         .remove         = stw481x_remove,
 243         .id_table       = stw481x_id,
 244 };
 245
 246 module_i2c_driver(stw481x_driver);
 247
 248 MODULE_AUTHOR("Linus Walleij");
 249 MODULE_DESCRIPTION("STw481x PMIC driver");
 250 MODULE_LICENSE("GPL v2");