diff options
Diffstat (limited to 'target/linux/cns3xxx/files/drivers/i2c/busses/i2c-cns3xxx.c')
| -rw-r--r-- | target/linux/cns3xxx/files/drivers/i2c/busses/i2c-cns3xxx.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/target/linux/cns3xxx/files/drivers/i2c/busses/i2c-cns3xxx.c b/target/linux/cns3xxx/files/drivers/i2c/busses/i2c-cns3xxx.c new file mode 100644 index 0000000..7acff37 --- /dev/null +++ b/target/linux/cns3xxx/files/drivers/i2c/busses/i2c-cns3xxx.c @@ -0,0 +1,374 @@ +/* + * Cavium CNS3xxx I2C Host Controller + * + * Copyright 2010 Cavium Network + * Copyright 2012 Gateworks Corporation + * Chris Lang <clang@gateworks.com> + * Tim Harvey <tharvey@gateworks.com> + * + * This file is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, Version 2, as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <asm/io.h> +#include <linux/wait.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/slab.h> +#include <linux/clk.h> + +/* + * We need the memory map + */ + +#define I2C_MEM_MAP_ADDR(x) (i2c->base + x) +#define I2C_MEM_MAP_VALUE(x) (*((unsigned int volatile*)I2C_MEM_MAP_ADDR(x))) + +#define I2C_CONTROLLER_REG I2C_MEM_MAP_VALUE(0x00) +#define I2C_TIME_OUT_REG I2C_MEM_MAP_VALUE(0x04) +#define I2C_SLAVE_ADDRESS_REG I2C_MEM_MAP_VALUE(0x08) +#define I2C_WRITE_DATA_REG I2C_MEM_MAP_VALUE(0x0C) +#define I2C_READ_DATA_REG I2C_MEM_MAP_VALUE(0x10) +#define I2C_INTERRUPT_STATUS_REG I2C_MEM_MAP_VALUE(0x14) +#define I2C_INTERRUPT_ENABLE_REG I2C_MEM_MAP_VALUE(0x18) +#define I2C_TWI_OUT_DLY_REG I2C_MEM_MAP_VALUE(0x1C) + +#define I2C_BUS_ERROR_FLAG (0x1) +#define I2C_ACTION_DONE_FLAG (0x2) + +#define CNS3xxx_I2C_ENABLE() (I2C_CONTROLLER_REG) |= ((unsigned int)0x1 << 31) +#define CNS3xxx_I2C_DISABLE() (I2C_CONTROLLER_REG) &= ~((unsigned int)0x1 << 31) +#define CNS3xxx_I2C_ENABLE_INTR() (I2C_INTERRUPT_ENABLE_REG) |= 0x03 +#define CNS3xxx_I2C_DISABLE_INTR() (I2C_INTERRUPT_ENABLE_REG) &= 0xfc + +#define TWI_TIMEOUT (10*HZ) +#define I2C_100KHZ 100000 +#define I2C_200KHZ 200000 +#define I2C_300KHZ 300000 +#define I2C_400KHZ 400000 + +#define CNS3xxx_I2C_CLK I2C_100KHZ + +#define STATE_DONE 1 +#define STATE_ERROR 2 + +struct cns3xxx_i2c { + struct device *dev; + void __iomem *base; /* virtual */ + wait_queue_head_t wait; + struct i2c_adapter adap; + struct i2c_msg *msg; + u8 state; /* see STATE_ */ + u8 error; /* see TWI_STATUS register */ + int rd_wr_len; + u8 *buf; +}; + +static u32 cns3xxx_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static int +cns3xxx_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg) +{ + struct cns3xxx_i2c *i2c = i2c_get_adapdata(adap); + int i, j; + u8 buf[1] = { 0 }; + + if (msg->len == 0) { + /* + * We are probably doing a probe for a device here, + * so set the length to one, and data to 0 + */ + msg->len = 1; + i2c->buf = buf; + } else { + i2c->buf = msg->buf; + } + + if (msg->flags & I2C_M_TEN) { + printk + ("%s:%d: Presently the driver does not handle extended addressing\n", + __FUNCTION__, __LINE__); + return -EINVAL; + } + i2c->msg = msg; + + for (i = 0; i < msg->len; i++) { + if (msg->len - i >= 4) + i2c->rd_wr_len = 3; + else + i2c->rd_wr_len = msg->len - i - 1; + + // Set Data Width and TWI_EN + I2C_CONTROLLER_REG = 0x80000000 | (i2c->rd_wr_len << 2) | (i2c->rd_wr_len); + + // Clear Write Reg + I2C_WRITE_DATA_REG = 0; + + // Set the slave address + I2C_SLAVE_ADDRESS_REG = (msg->addr << 1); + + // Are we Writing + if (!(msg->flags & I2C_M_RD)) { + I2C_CONTROLLER_REG |= (1 << 4); + if (i != 0) { + /* + * We need to set the address in the first byte. + * The base address is going to be in buf[0] and then + * it needs to be incremented by i - 1. + */ + i2c->buf--; + *i2c->buf = buf[0] + i - 1; + + if (i2c->rd_wr_len < 3) { + i += i2c->rd_wr_len; + i2c->rd_wr_len++; + I2C_CONTROLLER_REG = 0x80000000 | (1 << 4) | (i2c->rd_wr_len << 2) | (i2c->rd_wr_len); + } else { + i += i2c->rd_wr_len - 1; + } + } else { + i += i2c->rd_wr_len; + buf[0] = *i2c->buf; + } + for (j = 0; j <= i2c->rd_wr_len; j++) { + I2C_WRITE_DATA_REG |= ((*i2c->buf++) << (8 * j)); + } + } else { + i += i2c->rd_wr_len; + } + + // Start the Transfer + i2c->state = 0; // Clear out the State + i2c->error = 0; + I2C_CONTROLLER_REG |= (1 << 6); + + if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || + (i2c->state == STATE_DONE), TWI_TIMEOUT)) { + if (i2c->state == STATE_ERROR) { + dev_dbg(i2c->dev, "controller error: 0x%2x", i2c->error); + return -EAGAIN; // try again + } + } else { + dev_err(i2c->dev, "controller timed out " + "waiting for start condition to finish\n"); + return -ETIMEDOUT; + } + } + return 0; +} + +static int +cns3xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + int i; + int ret; + for (i = 0; i < num; i++) + { + ret = cns3xxx_i2c_xfer_msg(adap, &msgs[i]); + if (ret < 0) { + return ret; + } + } + return num; +} + + +static struct i2c_algorithm cns3xxx_i2c_algo = { + .master_xfer = cns3xxx_i2c_xfer, + .functionality = cns3xxx_i2c_func, +}; + +static struct i2c_adapter cns3xxx_i2c_adapter = { + .owner = THIS_MODULE, + .algo = &cns3xxx_i2c_algo, + .algo_data = NULL, + .nr = 0, + .name = "CNS3xxx I2C 0", + .retries = 5, +}; + +static void cns3xxx_i2c_adapter_init(struct cns3xxx_i2c *i2c) +{ + struct clk *clk; + + clk = devm_clk_get(i2c->dev, "cpu"); + if (WARN_ON(!clk)) + return; + + /* Disable the I2C */ + I2C_CONTROLLER_REG = 0; /* Disabled the I2C */ + + /* Check the Reg Dump when testing */ + I2C_TIME_OUT_REG = + (((((clk_get_rate(clk) / (2 * CNS3xxx_I2C_CLK)) - + 1) & 0x3FF) << 8) | (1 << 7) | 0x7F); + I2C_TWI_OUT_DLY_REG |= 0x3; + + /* Enable The Interrupt */ + CNS3xxx_I2C_ENABLE_INTR(); + + /* Clear Interrupt Status (0x2 | 0x1) */ + I2C_INTERRUPT_STATUS_REG |= (I2C_ACTION_DONE_FLAG | I2C_BUS_ERROR_FLAG); + + /* Enable the I2C Controller */ + CNS3xxx_I2C_ENABLE(); +} + +static irqreturn_t cns3xxx_i2c_isr(int irq, void *dev_id) +{ + struct cns3xxx_i2c *i2c = dev_id; + int i; + uint32_t stat = I2C_INTERRUPT_STATUS_REG; + + /* Clear Interrupt */ + I2C_INTERRUPT_STATUS_REG |= 0x1; + + if (stat & I2C_BUS_ERROR_FLAG) { + i2c->state = STATE_ERROR; + i2c->error = (I2C_INTERRUPT_STATUS_REG & 0xff00)>>8; + } else { + if (i2c->msg->flags & I2C_M_RD) { + for (i = 0; i <= i2c->rd_wr_len; i++) + { + *i2c->buf++ = ((I2C_READ_DATA_REG >> (8 * i)) & 0xff); + } + } + i2c->state = STATE_DONE; + } + wake_up(&i2c->wait); + return IRQ_HANDLED; +} + +static int cns3xxx_i2c_probe(struct platform_device *pdev) +{ + struct cns3xxx_i2c *i2c; + struct resource *res, *res2; + int ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + printk("%s: IORESOURCE_MEM not defined \n", __FUNCTION__); + return -ENODEV; + } + + res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!res2) { + printk("%s: IORESOURCE_IRQ not defined \n", __FUNCTION__); + return -ENODEV; + } + + i2c = kzalloc(sizeof(*i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + if (!request_mem_region(res->start, res->end - res->start + 1, + pdev->name)) { + dev_err(&pdev->dev, "Memory region busy\n"); + ret = -EBUSY; + goto request_mem_failed; + } + + i2c->dev = &pdev->dev; + i2c->base = ioremap(res->start, res->end - res->start + 1); + if (!i2c->base) { + dev_err(&pdev->dev, "Unable to map registers\n"); + ret = -EIO; + goto map_failed; + } + + cns3xxx_i2c_adapter_init(i2c); + + init_waitqueue_head(&i2c->wait); + ret = request_irq(res2->start, cns3xxx_i2c_isr, 0, pdev->name, i2c); + if (ret) { + dev_err(&pdev->dev, "Cannot claim IRQ\n"); + goto request_irq_failed; + } + + platform_set_drvdata(pdev, i2c); + i2c->adap = cns3xxx_i2c_adapter; + i2c_set_adapdata(&i2c->adap, i2c); + i2c->adap.dev.parent = &pdev->dev; + + /* add i2c adapter to i2c tree */ + ret = i2c_add_numbered_adapter(&i2c->adap); + if (ret) { + dev_err(&pdev->dev, "Failed to add adapter\n"); + goto add_adapter_failed; + } + + return 0; + + add_adapter_failed: + free_irq(res2->start, i2c); + request_irq_failed: + iounmap(i2c->base); + map_failed: + release_mem_region(res->start, res->end - res->start + 1); + request_mem_failed: + kfree(i2c); + + return ret; +} + +static int cns3xxx_i2c_remove(struct platform_device *pdev) +{ + struct cns3xxx_i2c *i2c = platform_get_drvdata(pdev); + struct resource *res; + + /* disable i2c logic */ + CNS3xxx_I2C_DISABLE_INTR(); + CNS3xxx_I2C_DISABLE(); + /* remove adapter & data */ + i2c_del_adapter(&i2c->adap); + platform_set_drvdata(pdev, NULL); + + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (res) + free_irq(res->start, i2c); + + iounmap(i2c->base); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res) + release_mem_region(res->start, res->end - res->start + 1); + + kfree(i2c); + + return 0; +} + +static struct platform_driver cns3xxx_i2c_driver = { + .probe = cns3xxx_i2c_probe, + .remove = cns3xxx_i2c_remove, + .driver = { + .owner = THIS_MODULE, + .name = "cns3xxx-i2c", + }, +}; + +static int __init cns3xxx_i2c_init(void) +{ + return platform_driver_register(&cns3xxx_i2c_driver); +} + +static void __exit cns3xxx_i2c_exit(void) +{ + platform_driver_unregister(&cns3xxx_i2c_driver); +} + +module_init(cns3xxx_i2c_init); +module_exit(cns3xxx_i2c_exit); + +MODULE_AUTHOR("Cavium Networks"); +MODULE_DESCRIPTION("Cavium CNS3XXX I2C Controller"); +MODULE_LICENSE("GPL"); |