linux/drivers/i2c/busses/i2c-thunderx-pcidrv.c
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   1/*
   2 * Cavium ThunderX i2c driver.
   3 *
   4 * Copyright (C) 2015,2016 Cavium Inc.
   5 * Authors: Fred Martin <fmartin@caviumnetworks.com>
   6 *          Jan Glauber <jglauber@cavium.com>
   7 *
   8 * This file is licensed under the terms of the GNU General Public
   9 * License version 2. This program is licensed "as is" without any
  10 * warranty of any kind, whether express or implied.
  11 */
  12
  13#include <linux/acpi.h>
  14#include <linux/clk.h>
  15#include <linux/delay.h>
  16#include <linux/i2c.h>
  17#include <linux/i2c-smbus.h>
  18#include <linux/interrupt.h>
  19#include <linux/kernel.h>
  20#include <linux/module.h>
  21#include <linux/of_irq.h>
  22#include <linux/pci.h>
  23
  24#include "i2c-octeon-core.h"
  25
  26#define DRV_NAME "i2c-thunderx"
  27
  28#define PCI_DEVICE_ID_THUNDER_TWSI      0xa012
  29
  30#define SYS_FREQ_DEFAULT                700000000
  31
  32#define TWSI_INT_ENA_W1C                0x1028
  33#define TWSI_INT_ENA_W1S                0x1030
  34
  35/*
  36 * Enable the CORE interrupt.
  37 * The interrupt will be asserted when there is non-STAT_IDLE state in the
  38 * SW_TWSI_EOP_TWSI_STAT register.
  39 */
  40static void thunder_i2c_int_enable(struct octeon_i2c *i2c)
  41{
  42        octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
  43                                i2c->twsi_base + TWSI_INT_ENA_W1S);
  44}
  45
  46/*
  47 * Disable the CORE interrupt.
  48 */
  49static void thunder_i2c_int_disable(struct octeon_i2c *i2c)
  50{
  51        octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
  52                                i2c->twsi_base + TWSI_INT_ENA_W1C);
  53}
  54
  55static void thunder_i2c_hlc_int_enable(struct octeon_i2c *i2c)
  56{
  57        octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
  58                                i2c->twsi_base + TWSI_INT_ENA_W1S);
  59}
  60
  61static void thunder_i2c_hlc_int_disable(struct octeon_i2c *i2c)
  62{
  63        octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
  64                                i2c->twsi_base + TWSI_INT_ENA_W1C);
  65}
  66
  67static u32 thunderx_i2c_functionality(struct i2c_adapter *adap)
  68{
  69        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
  70               I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL;
  71}
  72
  73static const struct i2c_algorithm thunderx_i2c_algo = {
  74        .master_xfer = octeon_i2c_xfer,
  75        .functionality = thunderx_i2c_functionality,
  76};
  77
  78static struct i2c_adapter thunderx_i2c_ops = {
  79        .owner  = THIS_MODULE,
  80        .name   = "ThunderX adapter",
  81        .algo   = &thunderx_i2c_algo,
  82};
  83
  84static void thunder_i2c_clock_enable(struct device *dev, struct octeon_i2c *i2c)
  85{
  86        int ret;
  87
  88        i2c->clk = clk_get(dev, NULL);
  89        if (IS_ERR(i2c->clk)) {
  90                i2c->clk = NULL;
  91                goto skip;
  92        }
  93
  94        ret = clk_prepare_enable(i2c->clk);
  95        if (ret)
  96                goto skip;
  97        i2c->sys_freq = clk_get_rate(i2c->clk);
  98
  99skip:
 100        if (!i2c->sys_freq)
 101                i2c->sys_freq = SYS_FREQ_DEFAULT;
 102}
 103
 104static void thunder_i2c_clock_disable(struct device *dev, struct clk *clk)
 105{
 106        if (!clk)
 107                return;
 108        clk_disable_unprepare(clk);
 109        clk_put(clk);
 110}
 111
 112static int thunder_i2c_smbus_setup_of(struct octeon_i2c *i2c,
 113                                      struct device_node *node)
 114{
 115        u32 type;
 116
 117        if (!node)
 118                return -EINVAL;
 119
 120        i2c->alert_data.irq = irq_of_parse_and_map(node, 0);
 121        if (!i2c->alert_data.irq)
 122                return -EINVAL;
 123
 124        type = irqd_get_trigger_type(irq_get_irq_data(i2c->alert_data.irq));
 125        i2c->alert_data.alert_edge_triggered =
 126                (type & IRQ_TYPE_LEVEL_MASK) ? 1 : 0;
 127
 128        i2c->ara = i2c_setup_smbus_alert(&i2c->adap, &i2c->alert_data);
 129        if (!i2c->ara)
 130                return -ENODEV;
 131        return 0;
 132}
 133
 134static int thunder_i2c_smbus_setup(struct octeon_i2c *i2c,
 135                                   struct device_node *node)
 136{
 137        /* TODO: ACPI support */
 138        if (!acpi_disabled)
 139                return -EOPNOTSUPP;
 140
 141        return thunder_i2c_smbus_setup_of(i2c, node);
 142}
 143
 144static void thunder_i2c_smbus_remove(struct octeon_i2c *i2c)
 145{
 146        if (i2c->ara)
 147                i2c_unregister_device(i2c->ara);
 148}
 149
 150static int thunder_i2c_probe_pci(struct pci_dev *pdev,
 151                                 const struct pci_device_id *ent)
 152{
 153        struct device *dev = &pdev->dev;
 154        struct octeon_i2c *i2c;
 155        int ret;
 156
 157        i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
 158        if (!i2c)
 159                return -ENOMEM;
 160
 161        i2c->roff.sw_twsi = 0x1000;
 162        i2c->roff.twsi_int = 0x1010;
 163        i2c->roff.sw_twsi_ext = 0x1018;
 164
 165        i2c->dev = dev;
 166        pci_set_drvdata(pdev, i2c);
 167        ret = pcim_enable_device(pdev);
 168        if (ret)
 169                return ret;
 170
 171        ret = pci_request_regions(pdev, DRV_NAME);
 172        if (ret)
 173                return ret;
 174
 175        i2c->twsi_base = pcim_iomap(pdev, 0, pci_resource_len(pdev, 0));
 176        if (!i2c->twsi_base)
 177                return -EINVAL;
 178
 179        thunder_i2c_clock_enable(dev, i2c);
 180        ret = device_property_read_u32(dev, "clock-frequency", &i2c->twsi_freq);
 181        if (ret)
 182                i2c->twsi_freq = 100000;
 183
 184        init_waitqueue_head(&i2c->queue);
 185
 186        i2c->int_enable = thunder_i2c_int_enable;
 187        i2c->int_disable = thunder_i2c_int_disable;
 188        i2c->hlc_int_enable = thunder_i2c_hlc_int_enable;
 189        i2c->hlc_int_disable = thunder_i2c_hlc_int_disable;
 190
 191        ret = pci_enable_msix(pdev, &i2c->i2c_msix, 1);
 192        if (ret)
 193                goto error;
 194
 195        ret = devm_request_irq(dev, i2c->i2c_msix.vector, octeon_i2c_isr, 0,
 196                               DRV_NAME, i2c);
 197        if (ret)
 198                goto error;
 199
 200        ret = octeon_i2c_init_lowlevel(i2c);
 201        if (ret)
 202                goto error;
 203
 204        octeon_i2c_set_clock(i2c);
 205
 206        i2c->adap = thunderx_i2c_ops;
 207        i2c->adap.retries = 5;
 208        i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info;
 209        i2c->adap.dev.parent = dev;
 210        i2c->adap.dev.of_node = pdev->dev.of_node;
 211        snprintf(i2c->adap.name, sizeof(i2c->adap.name),
 212                 "Cavium ThunderX i2c adapter at %s", dev_name(dev));
 213        i2c_set_adapdata(&i2c->adap, i2c);
 214
 215        ret = i2c_add_adapter(&i2c->adap);
 216        if (ret)
 217                goto error;
 218
 219        dev_info(i2c->dev, "Probed. Set system clock to %u\n", i2c->sys_freq);
 220
 221        ret = thunder_i2c_smbus_setup(i2c, pdev->dev.of_node);
 222        if (ret)
 223                dev_info(dev, "SMBUS alert not active on this bus\n");
 224
 225        return 0;
 226
 227error:
 228        thunder_i2c_clock_disable(dev, i2c->clk);
 229        return ret;
 230}
 231
 232static void thunder_i2c_remove_pci(struct pci_dev *pdev)
 233{
 234        struct octeon_i2c *i2c = pci_get_drvdata(pdev);
 235
 236        thunder_i2c_smbus_remove(i2c);
 237        thunder_i2c_clock_disable(&pdev->dev, i2c->clk);
 238        i2c_del_adapter(&i2c->adap);
 239}
 240
 241static const struct pci_device_id thunder_i2c_pci_id_table[] = {
 242        { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_THUNDER_TWSI) },
 243        { 0, }
 244};
 245
 246MODULE_DEVICE_TABLE(pci, thunder_i2c_pci_id_table);
 247
 248static struct pci_driver thunder_i2c_pci_driver = {
 249        .name           = DRV_NAME,
 250        .id_table       = thunder_i2c_pci_id_table,
 251        .probe          = thunder_i2c_probe_pci,
 252        .remove         = thunder_i2c_remove_pci,
 253};
 254
 255module_pci_driver(thunder_i2c_pci_driver);
 256
 257MODULE_LICENSE("GPL");
 258MODULE_AUTHOR("Fred Martin <fmartin@caviumnetworks.com>");
 259MODULE_DESCRIPTION("I2C-Bus adapter for Cavium ThunderX SOC");
 260