| /* |
| * i2c-ocores.c: I2C bus driver for OpenCores I2C controller |
| * (http://www.opencores.org/projects.cgi/web/i2c/overview). |
| * |
| * Peter Korsgaard <jacmet@sunsite.dk> |
| * |
| * 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/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/errno.h> |
| #include <linux/platform_device.h> |
| #include <linux/i2c.h> |
| #include <linux/interrupt.h> |
| #include <linux/wait.h> |
| #include <linux/i2c-ocores.h> |
| #include <linux/slab.h> |
| #include <linux/io.h> |
| |
| struct ocores_i2c { |
| void __iomem *base; |
| int regstep; |
| wait_queue_head_t wait; |
| struct i2c_adapter adap; |
| struct i2c_msg *msg; |
| int pos; |
| int nmsgs; |
| int state; /* see STATE_ */ |
| int clock_khz; |
| }; |
| |
| /* registers */ |
| #define OCI2C_PRELOW 0 |
| #define OCI2C_PREHIGH 1 |
| #define OCI2C_CONTROL 2 |
| #define OCI2C_DATA 3 |
| #define OCI2C_CMD 4 /* write only */ |
| #define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */ |
| |
| #define OCI2C_CTRL_IEN 0x40 |
| #define OCI2C_CTRL_EN 0x80 |
| |
| #define OCI2C_CMD_START 0x91 |
| #define OCI2C_CMD_STOP 0x41 |
| #define OCI2C_CMD_READ 0x21 |
| #define OCI2C_CMD_WRITE 0x11 |
| #define OCI2C_CMD_READ_ACK 0x21 |
| #define OCI2C_CMD_READ_NACK 0x29 |
| #define OCI2C_CMD_IACK 0x01 |
| |
| #define OCI2C_STAT_IF 0x01 |
| #define OCI2C_STAT_TIP 0x02 |
| #define OCI2C_STAT_ARBLOST 0x20 |
| #define OCI2C_STAT_BUSY 0x40 |
| #define OCI2C_STAT_NACK 0x80 |
| |
| #define STATE_DONE 0 |
| #define STATE_START 1 |
| #define STATE_WRITE 2 |
| #define STATE_READ 3 |
| #define STATE_ERROR 4 |
| |
| static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value) |
| { |
| iowrite8(value, i2c->base + reg * i2c->regstep); |
| } |
| |
| static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg) |
| { |
| return ioread8(i2c->base + reg * i2c->regstep); |
| } |
| |
| static void ocores_process(struct ocores_i2c *i2c) |
| { |
| struct i2c_msg *msg = i2c->msg; |
| u8 stat = oc_getreg(i2c, OCI2C_STATUS); |
| |
| if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) { |
| /* stop has been sent */ |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK); |
| wake_up(&i2c->wait); |
| return; |
| } |
| |
| /* error? */ |
| if (stat & OCI2C_STAT_ARBLOST) { |
| i2c->state = STATE_ERROR; |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); |
| return; |
| } |
| |
| if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) { |
| i2c->state = |
| (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE; |
| |
| if (stat & OCI2C_STAT_NACK) { |
| i2c->state = STATE_ERROR; |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); |
| return; |
| } |
| } else |
| msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA); |
| |
| /* end of msg? */ |
| if (i2c->pos == msg->len) { |
| i2c->nmsgs--; |
| i2c->msg++; |
| i2c->pos = 0; |
| msg = i2c->msg; |
| |
| if (i2c->nmsgs) { /* end? */ |
| /* send start? */ |
| if (!(msg->flags & I2C_M_NOSTART)) { |
| u8 addr = (msg->addr << 1); |
| |
| if (msg->flags & I2C_M_RD) |
| addr |= 1; |
| |
| i2c->state = STATE_START; |
| |
| oc_setreg(i2c, OCI2C_DATA, addr); |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); |
| return; |
| } else |
| i2c->state = (msg->flags & I2C_M_RD) |
| ? STATE_READ : STATE_WRITE; |
| } else { |
| i2c->state = STATE_DONE; |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); |
| return; |
| } |
| } |
| |
| if (i2c->state == STATE_READ) { |
| oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ? |
| OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK); |
| } else { |
| oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]); |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE); |
| } |
| } |
| |
| static irqreturn_t ocores_isr(int irq, void *dev_id) |
| { |
| struct ocores_i2c *i2c = dev_id; |
| |
| ocores_process(i2c); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) |
| { |
| struct ocores_i2c *i2c = i2c_get_adapdata(adap); |
| |
| i2c->msg = msgs; |
| i2c->pos = 0; |
| i2c->nmsgs = num; |
| i2c->state = STATE_START; |
| |
| oc_setreg(i2c, OCI2C_DATA, |
| (i2c->msg->addr << 1) | |
| ((i2c->msg->flags & I2C_M_RD) ? 1:0)); |
| |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); |
| |
| if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || |
| (i2c->state == STATE_DONE), HZ)) |
| return (i2c->state == STATE_DONE) ? num : -EIO; |
| else |
| return -ETIMEDOUT; |
| } |
| |
| static void ocores_init(struct ocores_i2c *i2c) |
| { |
| int prescale; |
| u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL); |
| |
| /* make sure the device is disabled */ |
| oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); |
| |
| prescale = (i2c->clock_khz / (5*100)) - 1; |
| oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff); |
| oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8); |
| |
| /* Init the device */ |
| oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK); |
| oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN); |
| } |
| |
| |
| static u32 ocores_func(struct i2c_adapter *adap) |
| { |
| return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; |
| } |
| |
| static const struct i2c_algorithm ocores_algorithm = { |
| .master_xfer = ocores_xfer, |
| .functionality = ocores_func, |
| }; |
| |
| static struct i2c_adapter ocores_adapter = { |
| .owner = THIS_MODULE, |
| .name = "i2c-ocores", |
| .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, |
| .algo = &ocores_algorithm, |
| }; |
| |
| |
| static int __devinit ocores_i2c_probe(struct platform_device *pdev) |
| { |
| struct ocores_i2c *i2c; |
| struct ocores_i2c_platform_data *pdata; |
| struct resource *res, *res2; |
| int ret; |
| int i; |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| if (!res) |
| return -ENODEV; |
| |
| res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0); |
| if (!res2) |
| return -ENODEV; |
| |
| pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data; |
| if (!pdata) |
| return -ENODEV; |
| |
| i2c = kzalloc(sizeof(*i2c), GFP_KERNEL); |
| if (!i2c) |
| return -ENOMEM; |
| |
| if (!request_mem_region(res->start, resource_size(res), |
| pdev->name)) { |
| dev_err(&pdev->dev, "Memory region busy\n"); |
| ret = -EBUSY; |
| goto request_mem_failed; |
| } |
| |
| i2c->base = ioremap(res->start, resource_size(res)); |
| if (!i2c->base) { |
| dev_err(&pdev->dev, "Unable to map registers\n"); |
| ret = -EIO; |
| goto map_failed; |
| } |
| |
| i2c->regstep = pdata->regstep; |
| i2c->clock_khz = pdata->clock_khz; |
| ocores_init(i2c); |
| |
| init_waitqueue_head(&i2c->wait); |
| ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c); |
| if (ret) { |
| dev_err(&pdev->dev, "Cannot claim IRQ\n"); |
| goto request_irq_failed; |
| } |
| |
| /* hook up driver to tree */ |
| platform_set_drvdata(pdev, i2c); |
| i2c->adap = ocores_adapter; |
| i2c_set_adapdata(&i2c->adap, i2c); |
| i2c->adap.dev.parent = &pdev->dev; |
| |
| /* add i2c adapter to i2c tree */ |
| ret = i2c_add_adapter(&i2c->adap); |
| if (ret) { |
| dev_err(&pdev->dev, "Failed to add adapter\n"); |
| goto add_adapter_failed; |
| } |
| |
| /* add in known devices to the bus */ |
| for (i = 0; i < pdata->num_devices; i++) |
| i2c_new_device(&i2c->adap, pdata->devices + i); |
| |
| return 0; |
| |
| add_adapter_failed: |
| free_irq(res2->start, i2c); |
| request_irq_failed: |
| iounmap(i2c->base); |
| map_failed: |
| release_mem_region(res->start, resource_size(res)); |
| request_mem_failed: |
| kfree(i2c); |
| |
| return ret; |
| } |
| |
| static int __devexit ocores_i2c_remove(struct platform_device* pdev) |
| { |
| struct ocores_i2c *i2c = platform_get_drvdata(pdev); |
| struct resource *res; |
| |
| /* disable i2c logic */ |
| oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL) |
| & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); |
| |
| /* 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, resource_size(res)); |
| |
| kfree(i2c); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM |
| static int ocores_i2c_suspend(struct platform_device *pdev, pm_message_t state) |
| { |
| struct ocores_i2c *i2c = platform_get_drvdata(pdev); |
| u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL); |
| |
| /* make sure the device is disabled */ |
| oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); |
| |
| return 0; |
| } |
| |
| static int ocores_i2c_resume(struct platform_device *pdev) |
| { |
| struct ocores_i2c *i2c = platform_get_drvdata(pdev); |
| |
| ocores_init(i2c); |
| |
| return 0; |
| } |
| #else |
| #define ocores_i2c_suspend NULL |
| #define ocores_i2c_resume NULL |
| #endif |
| |
| /* work with hotplug and coldplug */ |
| MODULE_ALIAS("platform:ocores-i2c"); |
| |
| static struct platform_driver ocores_i2c_driver = { |
| .probe = ocores_i2c_probe, |
| .remove = __devexit_p(ocores_i2c_remove), |
| .suspend = ocores_i2c_suspend, |
| .resume = ocores_i2c_resume, |
| .driver = { |
| .owner = THIS_MODULE, |
| .name = "ocores-i2c", |
| }, |
| }; |
| |
| static int __init ocores_i2c_init(void) |
| { |
| return platform_driver_register(&ocores_i2c_driver); |
| } |
| |
| static void __exit ocores_i2c_exit(void) |
| { |
| platform_driver_unregister(&ocores_i2c_driver); |
| } |
| |
| module_init(ocores_i2c_init); |
| module_exit(ocores_i2c_exit); |
| |
| MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>"); |
| MODULE_DESCRIPTION("OpenCores I2C bus driver"); |
| MODULE_LICENSE("GPL"); |