diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-stmp378x.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-stmp378x.c | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-stmp378x.c b/drivers/i2c/busses/i2c-stmp378x.c new file mode 100644 index 000000000000..4a01b55f5f07 --- /dev/null +++ b/drivers/i2c/busses/i2c-stmp378x.c @@ -0,0 +1,337 @@ +/* + * Freescale STMP378X I2C bus driver + * + * Author: Dmitrij Frasenyak <sed@embeddedalley.com> + * + * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ +/* #define DEBUG */ + +#include <linux/device.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/completion.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/io.h> + +#include <mach/regs-i2c.h> +#include <mach/regs-apbx.h> +#include <mach/i2c.h> + +static void reset_i2c_module(void) +{ + int count; + count = 1000; + HW_I2C_CTRL0_SET(BM_I2C_CTRL0_SFTRST); + udelay(10); /* Reseting the module can take multiple clocks.*/ + while (--count && (!(HW_I2C_CTRL0_RD() & BM_I2C_CTRL0_CLKGATE))) + udelay(1); + + if (!count) { + printk(KERN_ERR "timeout reseting the module\n"); + BUG(); + } + + /* take controller out of reset */ + HW_I2C_CTRL0_CLR(BM_I2C_CTRL0_SFTRST | BM_I2C_CTRL0_CLKGATE); + udelay(10); + HW_I2C_CTRL1_SET(0x0000FF00); /* Wil catch all error (IRQ mask) */ + +} + +/* + * Low level master read/write transaction. + */ +static int stmp378x_i2c_xfer_msg(struct i2c_adapter *adap, + struct i2c_msg *msg, int stop) +{ + struct stmp378x_i2c_dev *dev = i2c_get_adapdata(adap); + int err; + + init_completion(&dev->cmd_complete); + dev->cmd_err = 0; + + dev_dbg(dev->dev, " Start XFER ===>\n"); + dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n", + msg->addr, msg->len, msg->flags, stop); + + if ((msg->len == 0) || (msg->len > (PAGE_SIZE - 1))) + return -EINVAL; + + if (msg->flags & I2C_M_RD) { + hw_i2c_setup_read(msg->addr , + msg->buf , + msg->len, + stop ? BM_I2C_CTRL0_POST_SEND_STOP : 0); + + hw_i2c_run(1); /* read */ + } else { + hw_i2c_setup_write(msg->addr , + msg->buf , + msg->len, + stop ? BM_I2C_CTRL0_POST_SEND_STOP : 0); + + hw_i2c_run(0); /* write */ + } + + err = wait_for_completion_interruptible_timeout( + &dev->cmd_complete, + msecs_to_jiffies(1000) + ); + + if (err < 0) { + dev_dbg(dev->dev, "controler is timed out\n"); + return -ETIMEDOUT; + } + if ((!dev->cmd_err) && (msg->flags & I2C_M_RD)) + hw_i2c_finish_read(msg->buf, msg->len); + + dev_dbg(dev->dev, "<============= Done with err=%d\n", dev->cmd_err); + + + return dev->cmd_err; +} + + +static int +stmp378x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) +{ + int i; + int err; + + if (!msgs->len) + return -EINVAL; + + for (i = 0; i < num; i++) { + err = stmp378x_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1))); + if (err) + break; + } + + if (err == 0) + err = num; + + return err; +} + +static u32 +stmp378x_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); +} + +/* + * Debug. Don't need dma_irq for the final version + */ + +static irqreturn_t +stmp378x_i2c_dma_isr(int this_irq, void *dev_id) +{ + hw_i2c_clear_dma_interrupt(); + return IRQ_HANDLED; + +} + +#define I2C_IRQ_MASK 0x000000FF + +static irqreturn_t +stmp378x_i2c_isr(int this_irq, void *dev_id) +{ + struct stmp378x_i2c_dev *dev = dev_id; + u32 stat; + u32 done_mask = + BM_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | + BM_I2C_CTRL1_BUS_FREE_IRQ ; + + stat = HW_I2C_CTRL1_RD() & I2C_IRQ_MASK; + if (!stat) + return IRQ_NONE; + + if (stat & BM_I2C_CTRL1_NO_SLAVE_ACK_IRQ) { + dev->cmd_err = -EREMOTEIO; + + /* + * Stop DMA + * Clear NAK + */ + HW_I2C_CTRL1_SET(BM_I2C_CTRL1_CLR_GOT_A_NAK); + hw_i2c_reset_dma(); + reset_i2c_module(); + + complete(&dev->cmd_complete); + + goto done; + } + +/* Don't care about BM_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ */ + if (stat & ( + BM_I2C_CTRL1_EARLY_TERM_IRQ | + BM_I2C_CTRL1_MASTER_LOSS_IRQ | + BM_I2C_CTRL1_SLAVE_STOP_IRQ | + BM_I2C_CTRL1_SLAVE_IRQ + )) { + dev->cmd_err = -EIO; + complete(&dev->cmd_complete); + goto done; + } + if ((stat & done_mask) == done_mask) + complete(&dev->cmd_complete); + + +done: + HW_I2C_CTRL1_CLR(stat); + return IRQ_HANDLED; +} + +static const struct i2c_algorithm stmp378x_i2c_algo = { + .master_xfer = stmp378x_i2c_xfer, + .functionality = stmp378x_i2c_func, +}; + + +static int +stmp378x_i2c_probe(struct platform_device *pdev) +{ + struct stmp378x_i2c_dev *dev; + struct i2c_adapter *adap; + struct resource *irq; + int err = 0; + + /* NOTE: driver uses the static register mapping */ + dev = kzalloc(sizeof(struct stmp378x_i2c_dev), GFP_KERNEL); + if (!dev) { + dev_err(&pdev->dev, "no mem \n"); + return -ENOMEM; + } + + irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); /* Error */ + if (!irq) { + dev_err(&pdev->dev, "no err_irq resource\n"); + err = -ENODEV; + goto nores; + } + dev->irq_err = irq->start; + + irq = platform_get_resource(pdev, IORESOURCE_IRQ, 1); /* DMA */ + if (!irq) { + dev_err(&pdev->dev, "no dma_irq resource\n"); + err = -ENODEV; + goto nores; + } + + dev->irq_dma = irq->start; + dev->dev = &pdev->dev; + + err = request_irq(dev->irq_err, stmp378x_i2c_isr, 0, pdev->name, dev); + if (err) { + dev_err(&pdev->dev, "Can't get IRQ\n"); + goto no_err_irq; + } + + err = request_irq(dev->irq_dma, + stmp378x_i2c_dma_isr, + 0, pdev->name, dev); + if (err) { + dev_err(&pdev->dev, "Can't get IRQ\n"); + goto no_dma_irq; + } + + err = hw_i2c_init(&pdev->dev); + if (err) { + dev_err(&pdev->dev, "HW Init failed\n"); + goto init_failed; + } + + HW_I2C_CTRL1_SET(0x0000FF00); /* Will catch all error (IRQ mask) */ + + adap = &dev->adapter; + i2c_set_adapdata(adap, dev); + adap->owner = THIS_MODULE; + adap->class = I2C_CLASS_HWMON; + strncpy(adap->name, "378x I2C adapter", sizeof(adap->name)); + adap->algo = &stmp378x_i2c_algo; + adap->dev.parent = &pdev->dev; + + adap->nr = pdev->id; + err = i2c_add_numbered_adapter(adap); + if (err) { + dev_err(&pdev->dev, "Failed to add adapter\n"); + goto no_i2c_adapter; + + } + + return 0; + +no_i2c_adapter: + hw_i2c_stop(dev->dev); +init_failed: + free_irq(dev->irq_dma, dev); +no_dma_irq: + free_irq(dev->irq_err, dev); +no_err_irq: +nores: + kfree(dev); + return err; +} + +static int +stmp378x_i2c_remove(struct platform_device *pdev) +{ + struct stmp378x_i2c_dev *dev = platform_get_drvdata(pdev); + int res; + + res = i2c_del_adapter(&dev->adapter); + if (res) + return -EBUSY; + + hw_i2c_stop(dev->dev); + + platform_set_drvdata(pdev, NULL); + + free_irq(dev->irq_err, dev); + free_irq(dev->irq_dma, dev); + + kfree(dev); + return 0; +} + +static struct platform_driver stmp378x_i2c_driver = { + .probe = stmp378x_i2c_probe, + .remove = __devexit_p(stmp378x_i2c_remove), + .driver = { + .name = "i2c_stmp", + .owner = THIS_MODULE, + }, +}; + +/* I2C may be needed to bring up other drivers */ + +static int __init stmp378x_i2c_init_driver(void) +{ + return platform_driver_register(&stmp378x_i2c_driver); +} +subsys_initcall(stmp378x_i2c_init_driver); + +static void __exit stmp378x_i2c_exit_driver(void) +{ + platform_driver_unregister(&stmp378x_i2c_driver); +} +module_exit(stmp378x_i2c_exit_driver); + +MODULE_AUTHOR("old_chap@embeddedalley.com"); +MODULE_DESCRIPTION("IIC for Freescale STMP378x"); +MODULE_LICENSE("GPL"); |