diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/busses/i2c-puv3.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-puv3.c b/drivers/i2c/busses/i2c-puv3.c new file mode 100644 index 000000000..287088b8c --- /dev/null +++ b/drivers/i2c/busses/i2c-puv3.c @@ -0,0 +1,278 @@ +/* + * I2C driver for PKUnity-v3 SoC + * Code specific to PKUnity SoC and UniCore ISA + * + * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> + * Copyright (C) 2001-2010 Guan Xuetao + * + * This program 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/module.h> +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/clk.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <mach/hardware.h> + +/* + * Poll the i2c status register until the specified bit is set. + * Returns 0 if timed out (100 msec). + */ +static short poll_status(unsigned long bit) +{ + int loop_cntr = 1000; + + if (bit & I2C_STATUS_TFNF) { + do { + udelay(10); + } while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0)); + } else { + /* RXRDY handler */ + do { + if (readl(I2C_TAR) == I2C_TAR_EEPROM) + msleep(20); + else + udelay(10); + } while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0)); + } + + return (loop_cntr > 0); +} + +static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length) +{ + int i2c_reg = *buf; + + /* Read data */ + while (length--) { + if (!poll_status(I2C_STATUS_TFNF)) { + dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n"); + return -ETIMEDOUT; + } + + /* send addr */ + writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD); + + /* get ready to next write */ + i2c_reg++; + + /* send read CMD */ + writel(I2C_DATACMD_READ, I2C_DATACMD); + + /* wait until the Rx FIFO have available */ + if (!poll_status(I2C_STATUS_RFNE)) { + dev_dbg(&adap->dev, "RXRDY timeout\n"); + return -ETIMEDOUT; + } + + /* read the data to buf */ + *buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK); + buf++; + } + + return 0; +} + +static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length) +{ + int i2c_reg = *buf; + + /* Do nothing but storing the reg_num to a static variable */ + if (i2c_reg == -1) { + printk(KERN_WARNING "Error i2c reg\n"); + return -ETIMEDOUT; + } + + if (length == 1) + return 0; + + buf++; + length--; + while (length--) { + /* send addr */ + writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD); + + /* send write CMD */ + writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD); + + /* wait until the Rx FIFO have available */ + msleep(20); + + /* read the data to buf */ + i2c_reg++; + buf++; + } + + return 0; +} + +/* + * Generic i2c master transfer entrypoint. + * + */ +static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg, + int num) +{ + int i, ret; + unsigned char swap; + + /* Disable i2c */ + writel(I2C_ENABLE_DISABLE, I2C_ENABLE); + + /* Set the work mode and speed*/ + writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON); + + writel(pmsg->addr, I2C_TAR); + + /* Enable i2c */ + writel(I2C_ENABLE_ENABLE, I2C_ENABLE); + + dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num); + + for (i = 0; i < num; i++) { + dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i, + pmsg->flags & I2C_M_RD ? "read" : "writ", + pmsg->len, pmsg->len > 1 ? "s" : "", + pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr); + + if (pmsg->len && pmsg->buf) { /* sanity check */ + if (pmsg->flags & I2C_M_RD) + ret = xfer_read(adap, pmsg->buf, pmsg->len); + else + ret = xfer_write(adap, pmsg->buf, pmsg->len); + + if (ret) + return ret; + + } + dev_dbg(&adap->dev, "transfer complete\n"); + pmsg++; /* next message */ + } + + /* XXX: fixup be16_to_cpu in bq27x00_battery.c */ + if (pmsg->addr == I2C_TAR_PWIC) { + swap = pmsg->buf[0]; + pmsg->buf[0] = pmsg->buf[1]; + pmsg->buf[1] = swap; + } + + return i; +} + +/* + * Return list of supported functionality. + */ +static u32 puv3_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm puv3_i2c_algorithm = { + .master_xfer = puv3_i2c_xfer, + .functionality = puv3_i2c_func, +}; + +/* + * Main initialization routine. + */ +static int puv3_i2c_probe(struct platform_device *pdev) +{ + struct i2c_adapter *adapter; + struct resource *mem; + int rc; + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!mem) + return -ENODEV; + + if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c")) + return -EBUSY; + + adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL); + if (adapter == NULL) { + dev_err(&pdev->dev, "can't allocate interface!\n"); + rc = -ENOMEM; + goto fail_nomem; + } + snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x", + mem->start); + adapter->algo = &puv3_i2c_algorithm; + adapter->class = I2C_CLASS_HWMON; + adapter->dev.parent = &pdev->dev; + + platform_set_drvdata(pdev, adapter); + + adapter->nr = pdev->id; + rc = i2c_add_numbered_adapter(adapter); + if (rc) + goto fail_add_adapter; + + dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n"); + return 0; + +fail_add_adapter: + kfree(adapter); +fail_nomem: + release_mem_region(mem->start, resource_size(mem)); + + return rc; +} + +static int puv3_i2c_remove(struct platform_device *pdev) +{ + struct i2c_adapter *adapter = platform_get_drvdata(pdev); + struct resource *mem; + + i2c_del_adapter(adapter); + + put_device(&pdev->dev); + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + release_mem_region(mem->start, resource_size(mem)); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int puv3_i2c_suspend(struct device *dev) +{ + int poll_count; + /* Disable the IIC */ + writel(I2C_ENABLE_DISABLE, I2C_ENABLE); + for (poll_count = 0; poll_count < 50; poll_count++) { + if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE) + udelay(25); + } + + return 0; +} + +static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL); +#define PUV3_I2C_PM (&puv3_i2c_pm) + +#else +#define PUV3_I2C_PM NULL +#endif + +static struct platform_driver puv3_i2c_driver = { + .probe = puv3_i2c_probe, + .remove = puv3_i2c_remove, + .driver = { + .name = "PKUnity-v3-I2C", + .pm = PUV3_I2C_PM, + } +}; + +module_platform_driver(puv3_i2c_driver); + +MODULE_DESCRIPTION("PKUnity v3 I2C driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:puv3_i2c"); |