/* * Copyright (C) 2014 Broadcom Corporation * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation version 2. * * This program is distributed "as is" WITHOUT ANY WARRANTY of any * kind, whether express or implied; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #define CFG_OFFSET 0x00 #define CFG_RESET_SHIFT 31 #define CFG_EN_SHIFT 30 #define CFG_M_RETRY_CNT_SHIFT 16 #define CFG_M_RETRY_CNT_MASK 0x0f #define TIM_CFG_OFFSET 0x04 #define TIM_CFG_MODE_400_SHIFT 31 #define M_FIFO_CTRL_OFFSET 0x0c #define M_FIFO_RX_FLUSH_SHIFT 31 #define M_FIFO_TX_FLUSH_SHIFT 30 #define M_FIFO_RX_CNT_SHIFT 16 #define M_FIFO_RX_CNT_MASK 0x7f #define M_FIFO_RX_THLD_SHIFT 8 #define M_FIFO_RX_THLD_MASK 0x3f #define M_CMD_OFFSET 0x30 #define M_CMD_START_BUSY_SHIFT 31 #define M_CMD_STATUS_SHIFT 25 #define M_CMD_STATUS_MASK 0x07 #define M_CMD_STATUS_SUCCESS 0x0 #define M_CMD_STATUS_LOST_ARB 0x1 #define M_CMD_STATUS_NACK_ADDR 0x2 #define M_CMD_STATUS_NACK_DATA 0x3 #define M_CMD_STATUS_TIMEOUT 0x4 #define M_CMD_PROTOCOL_SHIFT 9 #define M_CMD_PROTOCOL_MASK 0xf #define M_CMD_PROTOCOL_BLK_WR 0x7 #define M_CMD_PROTOCOL_BLK_RD 0x8 #define M_CMD_PEC_SHIFT 8 #define M_CMD_RD_CNT_SHIFT 0 #define M_CMD_RD_CNT_MASK 0xff #define IE_OFFSET 0x38 #define IE_M_RX_FIFO_FULL_SHIFT 31 #define IE_M_RX_THLD_SHIFT 30 #define IE_M_START_BUSY_SHIFT 28 #define IE_M_TX_UNDERRUN_SHIFT 27 #define IS_OFFSET 0x3c #define IS_M_RX_FIFO_FULL_SHIFT 31 #define IS_M_RX_THLD_SHIFT 30 #define IS_M_START_BUSY_SHIFT 28 #define IS_M_TX_UNDERRUN_SHIFT 27 #define M_TX_OFFSET 0x40 #define M_TX_WR_STATUS_SHIFT 31 #define M_TX_DATA_SHIFT 0 #define M_TX_DATA_MASK 0xff #define M_RX_OFFSET 0x44 #define M_RX_STATUS_SHIFT 30 #define M_RX_STATUS_MASK 0x03 #define M_RX_PEC_ERR_SHIFT 29 #define M_RX_DATA_SHIFT 0 #define M_RX_DATA_MASK 0xff #define I2C_TIMEOUT_MSEC 50000 #define M_TX_RX_FIFO_SIZE 64 enum bus_speed_index { I2C_SPD_100K = 0, I2C_SPD_400K, }; struct bcm_iproc_i2c_dev { struct device *device; int irq; void __iomem *base; struct i2c_adapter adapter; unsigned int bus_speed; struct completion done; int xfer_is_done; struct i2c_msg *msg; /* bytes that have been transferred */ unsigned int tx_bytes; }; /* * Can be expanded in the future if more interrupt status bits are utilized */ #define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)) static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) { struct bcm_iproc_i2c_dev *iproc_i2c = data; u32 status = readl(iproc_i2c->base + IS_OFFSET); status &= ISR_MASK; if (!status) return IRQ_NONE; /* TX FIFO is empty and we have more data to send */ if (status & BIT(IS_M_TX_UNDERRUN_SHIFT)) { struct i2c_msg *msg = iproc_i2c->msg; unsigned int tx_bytes = msg->len - iproc_i2c->tx_bytes; unsigned int i; u32 val; /* can only fill up to the FIFO size */ tx_bytes = min_t(unsigned int, tx_bytes, M_TX_RX_FIFO_SIZE); for (i = 0; i < tx_bytes; i++) { /* start from where we left over */ unsigned int idx = iproc_i2c->tx_bytes + i; val = msg->buf[idx]; /* mark the last byte */ if (idx == msg->len - 1) { u32 tmp; val |= BIT(M_TX_WR_STATUS_SHIFT); /* * Since this is the last byte, we should * now disable TX FIFO underrun interrupt */ tmp = readl(iproc_i2c->base + IE_OFFSET); tmp &= ~BIT(IE_M_TX_UNDERRUN_SHIFT); writel(tmp, iproc_i2c->base + IE_OFFSET); } /* load data into TX FIFO */ writel(val, iproc_i2c->base + M_TX_OFFSET); } /* update number of transferred bytes */ iproc_i2c->tx_bytes += tx_bytes; } if (status & BIT(IS_M_START_BUSY_SHIFT)) { iproc_i2c->xfer_is_done = 1; complete_all(&iproc_i2c->done); } writel(status, iproc_i2c->base + IS_OFFSET); return IRQ_HANDLED; } static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *iproc_i2c) { u32 val; /* put controller in reset */ val = readl(iproc_i2c->base + CFG_OFFSET); val |= 1 << CFG_RESET_SHIFT; val &= ~(1 << CFG_EN_SHIFT); writel(val, iproc_i2c->base + CFG_OFFSET); /* wait 100 usec per spec */ udelay(100); /* bring controller out of reset */ val &= ~(1 << CFG_RESET_SHIFT); writel(val, iproc_i2c->base + CFG_OFFSET); /* flush TX/RX FIFOs and set RX FIFO threshold to zero */ val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); /* disable all interrupts */ writel(0, iproc_i2c->base + IE_OFFSET); /* clear all pending interrupts */ writel(0xffffffff, iproc_i2c->base + IS_OFFSET); return 0; } static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c, bool enable) { u32 val; val = readl(iproc_i2c->base + CFG_OFFSET); if (enable) val |= BIT(CFG_EN_SHIFT); else val &= ~BIT(CFG_EN_SHIFT); writel(val, iproc_i2c->base + CFG_OFFSET); } static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c, struct i2c_msg *msg) { u32 val; val = readl(iproc_i2c->base + M_CMD_OFFSET); val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK; switch (val) { case M_CMD_STATUS_SUCCESS: return 0; case M_CMD_STATUS_LOST_ARB: dev_dbg(iproc_i2c->device, "lost bus arbitration\n"); return -EAGAIN; case M_CMD_STATUS_NACK_ADDR: dev_dbg(iproc_i2c->device, "NAK addr:0x%02x\n", msg->addr); return -ENXIO; case M_CMD_STATUS_NACK_DATA: dev_dbg(iproc_i2c->device, "NAK data\n"); return -ENXIO; case M_CMD_STATUS_TIMEOUT: dev_dbg(iproc_i2c->device, "bus timeout\n"); return -ETIMEDOUT; default: dev_dbg(iproc_i2c->device, "unknown error code=%d\n", val); /* re-initialize i2c for recovery */ bcm_iproc_i2c_enable_disable(iproc_i2c, false); bcm_iproc_i2c_init(iproc_i2c); bcm_iproc_i2c_enable_disable(iproc_i2c, true); return -EIO; } } static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, struct i2c_msg *msg) { int ret, i; u8 addr; u32 val; unsigned int tx_bytes; unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MSEC); /* check if bus is busy */ if (!!(readl(iproc_i2c->base + M_CMD_OFFSET) & BIT(M_CMD_START_BUSY_SHIFT))) { dev_warn(iproc_i2c->device, "bus is busy\n"); return -EBUSY; } iproc_i2c->msg = msg; /* format and load slave address into the TX FIFO */ addr = i2c_8bit_addr_from_msg(msg); writel(addr, iproc_i2c->base + M_TX_OFFSET); /* * For a write transaction, load data into the TX FIFO. Only allow * loading up to TX FIFO size - 1 bytes of data since the first byte * has been used up by the slave address */ tx_bytes = min_t(unsigned int, msg->len, M_TX_RX_FIFO_SIZE - 1); if (!(msg->flags & I2C_M_RD)) { for (i = 0; i < tx_bytes; i++) { val = msg->buf[i]; /* mark the last byte */ if (i == msg->len - 1) val |= 1 << M_TX_WR_STATUS_SHIFT; writel(val, iproc_i2c->base + M_TX_OFFSET); } iproc_i2c->tx_bytes = tx_bytes; } /* mark as incomplete before starting the transaction */ reinit_completion(&iproc_i2c->done); iproc_i2c->xfer_is_done = 0; /* * Enable the "start busy" interrupt, which will be triggered after the * transaction is done, i.e., the internal start_busy bit, transitions * from 1 to 0. */ val = BIT(IE_M_START_BUSY_SHIFT); /* * If TX data size is larger than the TX FIFO, need to enable TX * underrun interrupt, which will be triggerred when the TX FIFO is * empty. When that happens we can then pump more data into the FIFO */ if (!(msg->flags & I2C_M_RD) && msg->len > iproc_i2c->tx_bytes) val |= BIT(IE_M_TX_UNDERRUN_SHIFT); writel(val, iproc_i2c->base + IE_OFFSET); /* * Now we can activate the transfer. For a read operation, specify the * number of bytes to read */ val = BIT(M_CMD_START_BUSY_SHIFT); if (msg->flags & I2C_M_RD) { val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | (msg->len << M_CMD_RD_CNT_SHIFT); } else { val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); } writel(val, iproc_i2c->base + M_CMD_OFFSET); time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left); /* disable all interrupts */ writel(0, iproc_i2c->base + IE_OFFSET); /* read it back to flush the write */ readl(iproc_i2c->base + IE_OFFSET); /* make sure the interrupt handler isn't running */ synchronize_irq(iproc_i2c->irq); if (!time_left && !iproc_i2c->xfer_is_done) { dev_err(iproc_i2c->device, "transaction timed out\n"); /* flush FIFOs */ val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); return -ETIMEDOUT; } ret = bcm_iproc_i2c_check_status(iproc_i2c, msg); if (ret) { /* flush both TX/RX FIFOs */ val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); writel(val, iproc_i2c->base + M_FIFO_CTRL_OFFSET); return ret; } /* * For a read operation, we now need to load the data from FIFO * into the memory buffer */ if (msg->flags & I2C_M_RD) { for (i = 0; i < msg->len; i++) { msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >> M_RX_DATA_SHIFT) & M_RX_DATA_MASK; } } return 0; } static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg msgs[], int num) { struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adapter); int ret, i; /* go through all messages */ for (i = 0; i < num; i++) { ret = bcm_iproc_i2c_xfer_single_msg(iproc_i2c, &msgs[i]); if (ret) { dev_dbg(iproc_i2c->device, "xfer failed\n"); return ret; } } return num; } static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm bcm_iproc_algo = { .master_xfer = bcm_iproc_i2c_xfer, .functionality = bcm_iproc_i2c_functionality, }; static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = { /* need to reserve one byte in the FIFO for the slave address */ .max_read_len = M_TX_RX_FIFO_SIZE - 1, }; static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c) { unsigned int bus_speed; u32 val; int ret = of_property_read_u32(iproc_i2c->device->of_node, "clock-frequency", &bus_speed); if (ret < 0) { dev_info(iproc_i2c->device, "unable to interpret clock-frequency DT property\n"); bus_speed = 100000; } if (bus_speed < 100000) { dev_err(iproc_i2c->device, "%d Hz bus speed not supported\n", bus_speed); dev_err(iproc_i2c->device, "valid speeds are 100khz and 400khz\n"); return -EINVAL; } else if (bus_speed < 400000) { bus_speed = 100000; } else { bus_speed = 400000; } iproc_i2c->bus_speed = bus_speed; val = readl(iproc_i2c->base + TIM_CFG_OFFSET); val &= ~(1 << TIM_CFG_MODE_400_SHIFT); val |= (bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT; writel(val, iproc_i2c->base + TIM_CFG_OFFSET); dev_info(iproc_i2c->device, "bus set to %u Hz\n", bus_speed); return 0; } static int bcm_iproc_i2c_probe(struct platform_device *pdev) { int irq, ret = 0; struct bcm_iproc_i2c_dev *iproc_i2c; struct i2c_adapter *adap; struct resource *res; iproc_i2c = devm_kzalloc(&pdev->dev, sizeof(*iproc_i2c), GFP_KERNEL); if (!iproc_i2c) return -ENOMEM; platform_set_drvdata(pdev, iproc_i2c); iproc_i2c->device = &pdev->dev; init_completion(&iproc_i2c->done); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); iproc_i2c->base = devm_ioremap_resource(iproc_i2c->device, res); if (IS_ERR(iproc_i2c->base)) return PTR_ERR(iproc_i2c->base); ret = bcm_iproc_i2c_init(iproc_i2c); if (ret) return ret; ret = bcm_iproc_i2c_cfg_speed(iproc_i2c); if (ret) return ret; irq = platform_get_irq(pdev, 0); if (irq <= 0) { dev_err(iproc_i2c->device, "no irq resource\n"); return irq; } iproc_i2c->irq = irq; ret = devm_request_irq(iproc_i2c->device, irq, bcm_iproc_i2c_isr, 0, pdev->name, iproc_i2c); if (ret < 0) { dev_err(iproc_i2c->device, "unable to request irq %i\n", irq); return ret; } bcm_iproc_i2c_enable_disable(iproc_i2c, true); adap = &iproc_i2c->adapter; i2c_set_adapdata(adap, iproc_i2c); strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name)); adap->algo = &bcm_iproc_algo; adap->quirks = &bcm_iproc_i2c_quirks; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; ret = i2c_add_adapter(adap); if (ret) { dev_err(iproc_i2c->device, "failed to add adapter\n"); return ret; } return 0; } static int bcm_iproc_i2c_remove(struct platform_device *pdev) { struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev); /* make sure there's no pending interrupt when we remove the adapter */ writel(0, iproc_i2c->base + IE_OFFSET); readl(iproc_i2c->base + IE_OFFSET); synchronize_irq(iproc_i2c->irq); i2c_del_adapter(&iproc_i2c->adapter); bcm_iproc_i2c_enable_disable(iproc_i2c, false); return 0; } #ifdef CONFIG_PM_SLEEP static int bcm_iproc_i2c_suspend(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev); /* make sure there's no pending interrupt when we go into suspend */ writel(0, iproc_i2c->base + IE_OFFSET); readl(iproc_i2c->base + IE_OFFSET); synchronize_irq(iproc_i2c->irq); /* now disable the controller */ bcm_iproc_i2c_enable_disable(iproc_i2c, false); return 0; } static int bcm_iproc_i2c_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev); int ret; u32 val; /* * Power domain could have been shut off completely in system deep * sleep, so re-initialize the block here */ ret = bcm_iproc_i2c_init(iproc_i2c); if (ret) return ret; /* configure to the desired bus speed */ val = readl(iproc_i2c->base + TIM_CFG_OFFSET); val &= ~(1 << TIM_CFG_MODE_400_SHIFT); val |= (iproc_i2c->bus_speed == 400000) << TIM_CFG_MODE_400_SHIFT; writel(val, iproc_i2c->base + TIM_CFG_OFFSET); bcm_iproc_i2c_enable_disable(iproc_i2c, true); return 0; } static const struct dev_pm_ops bcm_iproc_i2c_pm_ops = { .suspend_late = &bcm_iproc_i2c_suspend, .resume_early = &bcm_iproc_i2c_resume }; #define BCM_IPROC_I2C_PM_OPS (&bcm_iproc_i2c_pm_ops) #else #define BCM_IPROC_I2C_PM_OPS NULL #endif /* CONFIG_PM_SLEEP */ static const struct of_device_id bcm_iproc_i2c_of_match[] = { { .compatible = "brcm,iproc-i2c" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match); static struct platform_driver bcm_iproc_i2c_driver = { .driver = { .name = "bcm-iproc-i2c", .of_match_table = bcm_iproc_i2c_of_match, .pm = BCM_IPROC_I2C_PM_OPS, }, .probe = bcm_iproc_i2c_probe, .remove = bcm_iproc_i2c_remove, }; module_platform_driver(bcm_iproc_i2c_driver); MODULE_AUTHOR("Ray Jui "); MODULE_DESCRIPTION("Broadcom iProc I2C Driver"); MODULE_LICENSE("GPL v2");