// SPDX-License-Identifier: GPL-2.0 /* * Phytium I2C adapter driver (slave only). * * Copyright (c) 2021-2023 Phytium Technology Co., Ltd. */ #include #include #include #include #include #include #include #include #include "i2c-phytium-core.h" static void i2c_phytium_configure_fifo_slave(struct phytium_i2c_dev *dev) { /* Configure Tx/Rx FIFO threshold levels. */ phytium_writel(dev, 0, IC_TX_TL); phytium_writel(dev, 0, IC_RX_TL); /* Configure the I2C slave. */ phytium_writel(dev, dev->slave_cfg, IC_CON); phytium_writel(dev, IC_INTR_SLAVE_MASK, IC_INTR_MASK); } static int i2c_phytium_init_slave(struct phytium_i2c_dev *dev) { /* Disable the adapter. */ __i2c_phytium_disable(dev); /* Write SDA hold time if supported */ if (dev->sda_hold_time) phytium_writel(dev, dev->sda_hold_time, IC_SDA_HOLD); i2c_phytium_configure_fifo_slave(dev); return 0; } static int i2c_phytium_reg_slave(struct i2c_client *slave) { struct phytium_i2c_dev *dev = i2c_get_adapdata(slave->adapter); if (dev->slave) return -EBUSY; if (slave->flags & I2C_CLIENT_TEN) return -EAFNOSUPPORT; pm_runtime_get_sync(dev->dev); /* * Set slave address in the IC_SAR register, * the address to which the i2c responds. */ __i2c_phytium_disable_nowait(dev); phytium_writel(dev, slave->addr, IC_SAR); dev->slave = slave; __i2c_phytium_enable(dev); dev->cmd_err = 0; dev->msg_write_idx = 0; dev->msg_read_idx = 0; dev->msg_err = 0; dev->status = STATUS_IDLE; dev->abort_source = 0; dev->rx_outstanding = 0; return 0; } static int i2c_phytium_unreg_slave(struct i2c_client *slave) { struct phytium_i2c_dev *dev = i2c_get_adapdata(slave->adapter); dev->disable_int(dev); dev->disable(dev); dev->slave = NULL; pm_runtime_put(dev->dev); return 0; } static u32 i2c_phytium_read_clear_intrbits_slave(struct phytium_i2c_dev *dev) { u32 stat; /* * The IC_INTR_STAT register just indicates "enabled" interrupts. * Ths unmasked raw version of interrupt status bits are available * in the IC_RAW_INTR_STAT register. * * That is, * stat = phytium_readl(IC_INTR_STAT); * equals to, * stat = phytium_readl(IC_RAW_INTR_STAT) & phytium_readl(IC_INTR_MASK); * * The raw version might be useful for debugging purposes. */ stat = phytium_readl(dev, IC_INTR_STAT); /* * Do not use the IC_CLR_INTR register to clear interrupts, or * you'll miss some interrupts, triggered during the period from * phytium_readl(IC_INTR_STAT) to phytium_readl(IC_CLR_INTR). * * Instead, use the separately-prepared IC_CLR_* registers. */ if (stat & IC_INTR_TX_ABRT) phytium_readl(dev, IC_CLR_TX_ABRT); if (stat & IC_INTR_RX_UNDER) phytium_readl(dev, IC_CLR_RX_UNDER); if (stat & IC_INTR_RX_OVER) phytium_readl(dev, IC_CLR_RX_OVER); if (stat & IC_INTR_TX_OVER) phytium_readl(dev, IC_CLR_TX_OVER); if (stat & IC_INTR_RX_DONE) phytium_readl(dev, IC_CLR_RX_DONE); if (stat & IC_INTR_ACTIVITY) phytium_readl(dev, IC_CLR_ACTIVITY); if (stat & IC_INTR_STOP_DET) phytium_readl(dev, IC_CLR_STOP_DET); if (stat & IC_INTR_START_DET) phytium_readl(dev, IC_CLR_START_DET); if (stat & IC_INTR_GEN_CALL) phytium_readl(dev, IC_CLR_GEN_CALL); return stat; } /* * Interrupt service routine. This gets called whenever an I2C slave interrupt * occurs. */ static int i2c_phytium_irq_handler_slave(struct phytium_i2c_dev *dev) { u32 raw_stat, stat, enabled; u8 val, slave_activity; stat = phytium_readl(dev, IC_INTR_STAT); enabled = phytium_readl(dev, IC_ENABLE); raw_stat = phytium_readl(dev, IC_RAW_INTR_STAT); slave_activity = ((phytium_readl(dev, IC_STATUS) & IC_STATUS_SLAVE_ACTIVITY) >> 6); if (!enabled || !(raw_stat & ~IC_INTR_ACTIVITY) || !dev->slave) return 0; dev_dbg(dev->dev, "%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x : INTR_STAT=%#x\n", enabled, slave_activity, raw_stat, stat); if ((stat & IC_INTR_RX_FULL) && (stat & IC_INTR_STOP_DET)) i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val); if (stat & IC_INTR_RD_REQ) { if (slave_activity) { if (stat & IC_INTR_RX_FULL) { val = phytium_readl(dev, IC_DATA_CMD); if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED, &val)) { dev_vdbg(dev->dev, "Byte %X acked!", val); } phytium_readl(dev, IC_CLR_RD_REQ); stat = i2c_phytium_read_clear_intrbits_slave(dev); } else { phytium_readl(dev, IC_CLR_RD_REQ); phytium_readl(dev, IC_CLR_RX_UNDER); stat = i2c_phytium_read_clear_intrbits_slave(dev); } if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_REQUESTED, &val)) phytium_writel(dev, val, IC_DATA_CMD); } } if (stat & IC_INTR_RX_DONE) { if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_PROCESSED, &val)) phytium_readl(dev, IC_CLR_RX_DONE); i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val); stat = i2c_phytium_read_clear_intrbits_slave(dev); return 1; } if (stat & IC_INTR_RX_FULL) { val = phytium_readl(dev, IC_DATA_CMD); if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED, &val)) dev_vdbg(dev->dev, "Byte %X acked!", val); } else { i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val); stat = i2c_phytium_read_clear_intrbits_slave(dev); } return 1; } static irqreturn_t i2c_phytium_isr_slave(int this_irq, void *dev_id) { struct phytium_i2c_dev *dev = dev_id; int ret; i2c_phytium_read_clear_intrbits_slave(dev); ret = i2c_phytium_irq_handler_slave(dev); if (ret > 0) complete(&dev->cmd_complete); return IRQ_RETVAL(ret); } static const struct i2c_algorithm i2c_phytium_algo = { .functionality = i2c_phytium_func, .reg_slave = i2c_phytium_reg_slave, .unreg_slave = i2c_phytium_unreg_slave, }; int i2c_phytium_probe_slave(struct phytium_i2c_dev *dev) { struct i2c_adapter *adap = &dev->adapter; int ret; init_completion(&dev->cmd_complete); dev->init = i2c_phytium_init_slave; dev->disable = i2c_phytium_disable; dev->disable_int = i2c_phytium_disable_int; ret = dev->init(dev); if (ret) return ret; snprintf(adap->name, sizeof(adap->name), "Phytium I2C Slave adapter"); adap->retries = 3; adap->algo = &i2c_phytium_algo; adap->dev.parent = dev->dev; i2c_set_adapdata(adap, dev); ret = devm_request_irq(dev->dev, dev->irq, i2c_phytium_isr_slave, IRQF_SHARED, dev_name(dev->dev), dev); if (ret) { dev_err(dev->dev, "failure requesting irq %i: %d\n", dev->irq, ret); return ret; } ret = i2c_add_numbered_adapter(adap); if (ret) dev_err(dev->dev, "failure adding adapter: %d\n", ret); return ret; } EXPORT_SYMBOL_GPL(i2c_phytium_probe_slave);