/* * i2c-ocores.c: I2C bus driver for OpenCores I2C controller * (http://www.opencores.org/projects.cgi/web/i2c/overview). * * Peter Korsgaard * * 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. */ /* * Device tree configuration: * * Required properties: * - compatible : "opencores,i2c-ocores" * - reg : bus address start and address range size of device * - interrupts : interrupt number * - regstep : size of device registers in bytes * - clock-frequency : frequency of bus clock in Hz * * Example: * * i2c0: ocores@a0000000 { * compatible = "opencores,i2c-ocores"; * reg = <0xa0000000 0x8>; * interrupts = <10>; * * regstep = <1>; * clock-frequency = <20000000>; * * -- Devices connected on this I2C bus get * -- defined here; address- and size-cells * -- apply to these child devices * * #address-cells = <1>; * #size-cells = <0>; * * dummy@60 { * compatible = "dummy"; * reg = <60>; * }; * }; * */ #include #include #include #include #include #include #include #include #include #include #include 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, }; #ifdef CONFIG_OF static int ocores_i2c_of_probe(struct platform_device* pdev, struct ocores_i2c* i2c) { __be32* val; val = of_get_property(pdev->dev.of_node, "regstep", NULL); if (!val) { dev_err(&pdev->dev, "Missing required parameter 'regstep'"); return -ENODEV; } i2c->regstep = be32_to_cpup(val); val = of_get_property(pdev->dev.of_node, "clock-frequency", NULL); if (!val) { dev_err(&pdev->dev, "Missing required parameter 'clock-frequency'"); return -ENODEV; } i2c->clock_khz = be32_to_cpup(val) / 1000; return 0; } #else #define ocores_i2c_of_probe(pdev,i2c) -ENODEV #endif 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; i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res), pdev->name)) { dev_err(&pdev->dev, "Memory region busy\n"); return -EBUSY; } i2c->base = devm_ioremap_nocache(&pdev->dev, res->start, resource_size(res)); if (!i2c->base) { dev_err(&pdev->dev, "Unable to map registers\n"); return -EIO; } pdata = pdev->dev.platform_data; if (pdata) { i2c->regstep = pdata->regstep; i2c->clock_khz = pdata->clock_khz; } else { ret = ocores_i2c_of_probe(pdev, i2c); if (ret) return ret; } ocores_init(i2c); init_waitqueue_head(&i2c->wait); ret = devm_request_irq(&pdev->dev, res2->start, ocores_isr, 0, pdev->name, i2c); if (ret) { dev_err(&pdev->dev, "Cannot claim IRQ\n"); return ret; } /* 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; i2c->adap.dev.of_node = pdev->dev.of_node; /* add i2c adapter to i2c tree */ ret = i2c_add_adapter(&i2c->adap); if (ret) { dev_err(&pdev->dev, "Failed to add adapter\n"); return ret; } /* add in known devices to the bus */ if (pdata) { for (i = 0; i < pdata->num_devices; i++) i2c_new_device(&i2c->adap, pdata->devices + i); } return 0; } static int __devexit ocores_i2c_remove(struct platform_device* pdev) { struct ocores_i2c *i2c = platform_get_drvdata(pdev); /* 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); 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 static struct of_device_id ocores_i2c_match[] = { { .compatible = "opencores,i2c-ocores", }, {}, }; MODULE_DEVICE_TABLE(of, ocores_i2c_match); /* 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", .of_match_table = ocores_i2c_match, }, }; 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 "); MODULE_DESCRIPTION("OpenCores I2C bus driver"); MODULE_LICENSE("GPL");