root/drivers/i2c/busses/i2c-thunderx-pcidrv.c
/*
 * Cavium ThunderX i2c driver.
 *
 * Copyright (C) 2015,2016 Cavium Inc.
 * Authors: Fred Martin <fmartin@caviumnetworks.com>
 *          Jan Glauber <jglauber@cavium.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/i2c-smbus.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_irq.h>
#include <linux/pci.h>

#include "i2c-octeon-core.h"

#define DRV_NAME "i2c-thunderx"

#define PCI_DEVICE_ID_THUNDER_TWSI      0xa012

#define SYS_FREQ_DEFAULT                800000000
#define OTX2_REF_FREQ_DEFAULT           100000000

#define TWSI_INT_ENA_W1C                0x1028
#define TWSI_INT_ENA_W1S                0x1030

/*
 * Enable the CORE interrupt.
 * The interrupt will be asserted when there is non-STAT_IDLE state in the
 * SW_TWSI_EOP_TWSI_STAT register.
 */
static void thunder_i2c_int_enable(struct octeon_i2c *i2c)
{
        octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
                                i2c->twsi_base + TWSI_INT_ENA_W1S);
}

/*
 * Disable the CORE interrupt.
 */
static void thunder_i2c_int_disable(struct octeon_i2c *i2c)
{
        octeon_i2c_writeq_flush(TWSI_INT_CORE_INT,
                                i2c->twsi_base + TWSI_INT_ENA_W1C);
}

static void thunder_i2c_hlc_int_enable(struct octeon_i2c *i2c)
{
        octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
                                i2c->twsi_base + TWSI_INT_ENA_W1S);
}

static void thunder_i2c_hlc_int_disable(struct octeon_i2c *i2c)
{
        octeon_i2c_writeq_flush(TWSI_INT_ST_INT | TWSI_INT_TS_INT,
                                i2c->twsi_base + TWSI_INT_ENA_W1C);
}

static u32 thunderx_i2c_functionality(struct i2c_adapter *adap)
{
        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
               I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL;
}

static const struct i2c_algorithm thunderx_i2c_algo = {
        .xfer = octeon_i2c_xfer,
        .functionality = thunderx_i2c_functionality,
};

static const struct i2c_adapter thunderx_i2c_ops = {
        .owner  = THIS_MODULE,
        .name   = "ThunderX adapter",
        .algo   = &thunderx_i2c_algo,
};

static void thunder_i2c_clock_enable(struct device *dev, struct octeon_i2c *i2c)
{
        int ret;

        if (acpi_disabled) {
                /* DT */
                i2c->clk = clk_get(dev, NULL);
                if (IS_ERR(i2c->clk)) {
                        i2c->clk = NULL;
                        goto skip;
                }

                ret = clk_prepare_enable(i2c->clk);
                if (ret)
                        goto skip;
                i2c->sys_freq = clk_get_rate(i2c->clk);
        } else {
                /* ACPI */
                if (device_property_read_u32(dev, "sclk", &i2c->sys_freq))
                        device_property_read_u32(dev, "ioclk", &i2c->sys_freq);
        }

skip:
        if (!i2c->sys_freq)
                i2c->sys_freq = SYS_FREQ_DEFAULT;
}

static void thunder_i2c_clock_disable(struct device *dev, struct clk *clk)
{
        if (!clk)
                return;
        clk_disable_unprepare(clk);
        clk_put(clk);
}

static int thunder_i2c_smbus_setup_of(struct octeon_i2c *i2c,
                                      struct device_node *node)
{
        struct i2c_client *ara;

        if (!node)
                return -EINVAL;

        i2c->alert_data.irq = irq_of_parse_and_map(node, 0);
        if (!i2c->alert_data.irq)
                return -EINVAL;

        ara = i2c_new_smbus_alert_device(&i2c->adap, &i2c->alert_data);
        if (IS_ERR(ara))
                return PTR_ERR(ara);

        i2c->ara = ara;

        return 0;
}

static int thunder_i2c_smbus_setup(struct octeon_i2c *i2c,
                                   struct device_node *node)
{
        /* TODO: ACPI support */
        if (!acpi_disabled)
                return -EOPNOTSUPP;

        return thunder_i2c_smbus_setup_of(i2c, node);
}

static void thunder_i2c_smbus_remove(struct octeon_i2c *i2c)
{
        i2c_unregister_device(i2c->ara);
}

static int thunder_i2c_probe_pci(struct pci_dev *pdev,
                                 const struct pci_device_id *ent)
{
        struct device *dev = &pdev->dev;
        struct octeon_i2c *i2c;
        int ret;

        i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
        if (!i2c)
                return -ENOMEM;

        i2c->roff.sw_twsi = 0x1000;
        i2c->roff.twsi_int = 0x1010;
        i2c->roff.sw_twsi_ext = 0x1018;
        i2c->roff.mode = 0x1038;
        i2c->roff.block_ctl = 0x1048;
        i2c->roff.block_sts = 0x1050;
        i2c->roff.block_fifo = 0x1058;

        i2c->dev = dev;
        pci_set_drvdata(pdev, i2c);
        ret = pcim_enable_device(pdev);
        if (ret)
                return ret;

        ret = pcim_request_all_regions(pdev, DRV_NAME);
        if (ret)
                return ret;

        i2c->twsi_base = pcim_iomap(pdev, 0, pci_resource_len(pdev, 0));
        if (!i2c->twsi_base)
                return -EINVAL;

        thunder_i2c_clock_enable(dev, i2c);
        ret = device_property_read_u32(dev, "clock-frequency", &i2c->twsi_freq);
        if (ret)
                i2c->twsi_freq = I2C_MAX_STANDARD_MODE_FREQ;

        init_waitqueue_head(&i2c->queue);

        i2c->int_enable = thunder_i2c_int_enable;
        i2c->int_disable = thunder_i2c_int_disable;
        i2c->hlc_int_enable = thunder_i2c_hlc_int_enable;
        i2c->hlc_int_disable = thunder_i2c_hlc_int_disable;

        ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
        if (ret < 0)
                goto error;

        ret = devm_request_irq(dev, pci_irq_vector(pdev, 0), octeon_i2c_isr, 0,
                               DRV_NAME, i2c);
        if (ret)
                goto error;

        ret = octeon_i2c_init_lowlevel(i2c);
        if (ret)
                goto error;

        /*
         * For OcteonTX2 chips, set reference frequency to 100MHz
         * as refclk_src in TWSI_MODE register defaults to 100MHz.
         */
        if (octeon_i2c_is_otx2(pdev) && IS_LS_FREQ(i2c->twsi_freq))
                i2c->sys_freq = OTX2_REF_FREQ_DEFAULT;
        octeon_i2c_set_clock(i2c);

        i2c->adap = thunderx_i2c_ops;
        i2c->adap.retries = 5;
        i2c->adap.class = I2C_CLASS_HWMON;
        i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info;
        i2c->adap.dev.parent = dev;
        i2c->adap.dev.of_node = pdev->dev.of_node;
        i2c->adap.dev.fwnode = dev->fwnode;
        snprintf(i2c->adap.name, sizeof(i2c->adap.name),
                 "Cavium ThunderX i2c adapter at %s", dev_name(dev));
        i2c_set_adapdata(&i2c->adap, i2c);

        ret = i2c_add_adapter(&i2c->adap);
        if (ret)
                goto error;

        dev_info(i2c->dev, "Probed. Set system clock to %u\n", i2c->sys_freq);

        ret = thunder_i2c_smbus_setup(i2c, pdev->dev.of_node);
        if (ret)
                dev_info(dev, "SMBUS alert not active on this bus\n");

        return 0;

error:
        thunder_i2c_clock_disable(dev, i2c->clk);
        return ret;
}

static void thunder_i2c_remove_pci(struct pci_dev *pdev)
{
        struct octeon_i2c *i2c = pci_get_drvdata(pdev);

        thunder_i2c_smbus_remove(i2c);
        thunder_i2c_clock_disable(&pdev->dev, i2c->clk);
        i2c_del_adapter(&i2c->adap);
}

static const struct pci_device_id thunder_i2c_pci_id_table[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_THUNDER_TWSI) },
        { 0, }
};

MODULE_DEVICE_TABLE(pci, thunder_i2c_pci_id_table);

static struct pci_driver thunder_i2c_pci_driver = {
        .name           = DRV_NAME,
        .id_table       = thunder_i2c_pci_id_table,
        .probe          = thunder_i2c_probe_pci,
        .remove         = thunder_i2c_remove_pci,
};

module_pci_driver(thunder_i2c_pci_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Fred Martin <fmartin@caviumnetworks.com>");
MODULE_DESCRIPTION("I2C-Bus adapter for Cavium ThunderX SOC");