/* * i2c-ocores.c: I2C bus driver for OpenCores I2C controller * (http://www.opencores.org/projects.cgi/web/i2c/overview). * * Peter Korsgaard * * Support for the GRLIB port of the controller by * Andreas Larsson * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include struct ocores_i2c { void __iomem *base; u32 reg_shift; u32 reg_io_width; wait_queue_head_t wait; struct i2c_adapter adap; struct i2c_msg *msg; int pos; int nmsgs; int state; /* see STATE_ */ int clock_khz; void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value); u8 (*getreg)(struct ocores_i2c *i2c, int reg); }; /* 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 #define TYPE_OCORES 0 #define TYPE_GRLIB 1 static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value) { iowrite8(value, i2c->base + (reg << i2c->reg_shift)); } static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value) { iowrite16(value, i2c->base + (reg << i2c->reg_shift)); } static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value) { iowrite32(value, i2c->base + (reg << i2c->reg_shift)); } static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg) { return ioread8(i2c->base + (reg << i2c->reg_shift)); } static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg) { return ioread16(i2c->base + (reg << i2c->reg_shift)); } static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg) { return ioread32(i2c->base + (reg << i2c->reg_shift)); } static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value) { i2c->setreg(i2c, reg, value); } static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg) { return i2c->getreg(i2c, reg); } 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 struct of_device_id ocores_i2c_match[] = { { .compatible = "opencores,i2c-ocores", .data = (void *)TYPE_OCORES, }, { .compatible = "aeroflexgaisler,i2cmst", .data = (void *)TYPE_GRLIB, }, {}, }; MODULE_DEVICE_TABLE(of, ocores_i2c_match); #ifdef CONFIG_OF /* Read and write functions for the GRLIB port of the controller. Registers are * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one * register. The subsequent registers has their offset decreased accordingly. */ static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg) { u32 rd; int rreg = reg; if (reg != OCI2C_PRELOW) rreg--; rd = ioread32be(i2c->base + (rreg << i2c->reg_shift)); if (reg == OCI2C_PREHIGH) return (u8)(rd >> 8); else return (u8)rd; } static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value) { u32 curr, wr; int rreg = reg; if (reg != OCI2C_PRELOW) rreg--; if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) { curr = ioread32be(i2c->base + (rreg << i2c->reg_shift)); if (reg == OCI2C_PRELOW) wr = (curr & 0xff00) | value; else wr = (((u32)value) << 8) | (curr & 0xff); } else { wr = value; } iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift)); } static int ocores_i2c_of_probe(struct platform_device *pdev, struct ocores_i2c *i2c) { struct device_node *np = pdev->dev.of_node; const struct of_device_id *match; u32 val; if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) { /* no 'reg-shift', check for deprecated 'regstep' */ if (!of_property_read_u32(np, "regstep", &val)) { if (!is_power_of_2(val)) { dev_err(&pdev->dev, "invalid regstep %d\n", val); return -EINVAL; } i2c->reg_shift = ilog2(val); dev_warn(&pdev->dev, "regstep property deprecated, use reg-shift\n"); } } if (of_property_read_u32(np, "clock-frequency", &val)) { dev_err(&pdev->dev, "Missing required parameter 'clock-frequency'\n"); return -ENODEV; } i2c->clock_khz = val / 1000; of_property_read_u32(pdev->dev.of_node, "reg-io-width", &i2c->reg_io_width); match = of_match_node(ocores_i2c_match, pdev->dev.of_node); if (match && (long)match->data == TYPE_GRLIB) { dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n"); i2c->setreg = oc_setreg_grlib; i2c->getreg = oc_getreg_grlib; } return 0; } #else #define ocores_i2c_of_probe(pdev,i2c) -ENODEV #endif static int ocores_i2c_probe(struct platform_device *pdev) { struct ocores_i2c *i2c; struct ocores_i2c_platform_data *pdata; struct resource *res; int irq; int ret; int i; irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->base)) return PTR_ERR(i2c->base); pdata = pdev->dev.platform_data; if (pdata) { i2c->reg_shift = pdata->reg_shift; i2c->reg_io_width = pdata->reg_io_width; i2c->clock_khz = pdata->clock_khz; } else { ret = ocores_i2c_of_probe(pdev, i2c); if (ret) return ret; } if (i2c->reg_io_width == 0) i2c->reg_io_width = 1; /* Set to default value */ if (!i2c->setreg || !i2c->getreg) { switch (i2c->reg_io_width) { case 1: i2c->setreg = oc_setreg_8; i2c->getreg = oc_getreg_8; break; case 2: i2c->setreg = oc_setreg_16; i2c->getreg = oc_getreg_16; break; case 4: i2c->setreg = oc_setreg_32; i2c->getreg = oc_getreg_32; break; default: dev_err(&pdev->dev, "Unsupported I/O width (%d)\n", i2c->reg_io_width); return -EINVAL; } } ocores_init(i2c); init_waitqueue_head(&i2c->wait); ret = devm_request_irq(&pdev->dev, irq, 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); } else { of_i2c_register_devices(&i2c->adap); } return 0; } static int 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); return 0; } #ifdef CONFIG_PM_SLEEP static int ocores_i2c_suspend(struct device *dev) { struct ocores_i2c *i2c = dev_get_drvdata(dev); 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 device *dev) { struct ocores_i2c *i2c = dev_get_drvdata(dev); ocores_init(i2c); return 0; } static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume); #define OCORES_I2C_PM (&ocores_i2c_pm) #else #define OCORES_I2C_PM NULL #endif static struct platform_driver ocores_i2c_driver = { .probe = ocores_i2c_probe, .remove = ocores_i2c_remove, .driver = { .owner = THIS_MODULE, .name = "ocores-i2c", .of_match_table = ocores_i2c_match, .pm = OCORES_I2C_PM, }, }; module_platform_driver(ocores_i2c_driver); MODULE_AUTHOR("Peter Korsgaard "); MODULE_DESCRIPTION("OpenCores I2C bus driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:ocores-i2c");