mirror of
https://github.com/coolsnowwolf/lede.git
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a462d2b757
* target: add phytium support * kernel/video: add phytium platform ARM GPU support * config: add EFI support to phytium armv8 * target: phytium: remove rtl8821cs driver * target: phytium: refresh dts
263 lines
6.6 KiB
C
263 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Phytium I2C adapter driver (slave only).
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*
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* Copyright (c) 2021-2023 Phytium Technology Co., Ltd.
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*/
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/pm_runtime.h>
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#include "i2c-phytium-core.h"
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static void i2c_phytium_configure_fifo_slave(struct phytium_i2c_dev *dev)
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{
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/* Configure Tx/Rx FIFO threshold levels. */
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phytium_writel(dev, 0, IC_TX_TL);
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phytium_writel(dev, 0, IC_RX_TL);
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/* Configure the I2C slave. */
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phytium_writel(dev, dev->slave_cfg, IC_CON);
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phytium_writel(dev, IC_INTR_SLAVE_MASK, IC_INTR_MASK);
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}
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static int i2c_phytium_init_slave(struct phytium_i2c_dev *dev)
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{
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/* Disable the adapter. */
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__i2c_phytium_disable(dev);
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/* Write SDA hold time if supported */
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if (dev->sda_hold_time)
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phytium_writel(dev, dev->sda_hold_time, IC_SDA_HOLD);
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i2c_phytium_configure_fifo_slave(dev);
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return 0;
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}
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static int i2c_phytium_reg_slave(struct i2c_client *slave)
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{
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struct phytium_i2c_dev *dev = i2c_get_adapdata(slave->adapter);
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if (dev->slave)
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return -EBUSY;
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if (slave->flags & I2C_CLIENT_TEN)
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return -EAFNOSUPPORT;
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pm_runtime_get_sync(dev->dev);
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/*
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* Set slave address in the IC_SAR register,
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* the address to which the i2c responds.
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*/
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__i2c_phytium_disable_nowait(dev);
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phytium_writel(dev, slave->addr, IC_SAR);
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dev->slave = slave;
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__i2c_phytium_enable(dev);
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dev->cmd_err = 0;
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dev->msg_write_idx = 0;
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dev->msg_read_idx = 0;
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dev->msg_err = 0;
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dev->status = STATUS_IDLE;
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dev->abort_source = 0;
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dev->rx_outstanding = 0;
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return 0;
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}
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static int i2c_phytium_unreg_slave(struct i2c_client *slave)
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{
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struct phytium_i2c_dev *dev = i2c_get_adapdata(slave->adapter);
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dev->disable_int(dev);
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dev->disable(dev);
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dev->slave = NULL;
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pm_runtime_put(dev->dev);
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return 0;
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}
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static u32 i2c_phytium_read_clear_intrbits_slave(struct phytium_i2c_dev *dev)
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{
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u32 stat;
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/*
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* The IC_INTR_STAT register just indicates "enabled" interrupts.
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* Ths unmasked raw version of interrupt status bits are available
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* in the IC_RAW_INTR_STAT register.
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*
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* That is,
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* stat = phytium_readl(IC_INTR_STAT);
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* equals to,
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* stat = phytium_readl(IC_RAW_INTR_STAT) & phytium_readl(IC_INTR_MASK);
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*
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* The raw version might be useful for debugging purposes.
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*/
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stat = phytium_readl(dev, IC_INTR_STAT);
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/*
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* Do not use the IC_CLR_INTR register to clear interrupts, or
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* you'll miss some interrupts, triggered during the period from
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* phytium_readl(IC_INTR_STAT) to phytium_readl(IC_CLR_INTR).
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*
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* Instead, use the separately-prepared IC_CLR_* registers.
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*/
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if (stat & IC_INTR_TX_ABRT)
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phytium_readl(dev, IC_CLR_TX_ABRT);
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if (stat & IC_INTR_RX_UNDER)
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phytium_readl(dev, IC_CLR_RX_UNDER);
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if (stat & IC_INTR_RX_OVER)
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phytium_readl(dev, IC_CLR_RX_OVER);
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if (stat & IC_INTR_TX_OVER)
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phytium_readl(dev, IC_CLR_TX_OVER);
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if (stat & IC_INTR_RX_DONE)
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phytium_readl(dev, IC_CLR_RX_DONE);
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if (stat & IC_INTR_ACTIVITY)
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phytium_readl(dev, IC_CLR_ACTIVITY);
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if (stat & IC_INTR_STOP_DET)
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phytium_readl(dev, IC_CLR_STOP_DET);
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if (stat & IC_INTR_START_DET)
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phytium_readl(dev, IC_CLR_START_DET);
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if (stat & IC_INTR_GEN_CALL)
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phytium_readl(dev, IC_CLR_GEN_CALL);
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return stat;
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}
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/*
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* Interrupt service routine. This gets called whenever an I2C slave interrupt
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* occurs.
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*/
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static int i2c_phytium_irq_handler_slave(struct phytium_i2c_dev *dev)
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{
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u32 raw_stat, stat, enabled;
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u8 val, slave_activity;
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stat = phytium_readl(dev, IC_INTR_STAT);
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enabled = phytium_readl(dev, IC_ENABLE);
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raw_stat = phytium_readl(dev, IC_RAW_INTR_STAT);
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slave_activity = ((phytium_readl(dev, IC_STATUS) &
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IC_STATUS_SLAVE_ACTIVITY) >> 6);
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if (!enabled || !(raw_stat & ~IC_INTR_ACTIVITY) || !dev->slave)
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return 0;
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dev_dbg(dev->dev,
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"%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x : INTR_STAT=%#x\n",
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enabled, slave_activity, raw_stat, stat);
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if ((stat & IC_INTR_RX_FULL) && (stat & IC_INTR_STOP_DET))
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i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
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if (stat & IC_INTR_RD_REQ) {
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if (slave_activity) {
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if (stat & IC_INTR_RX_FULL) {
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val = phytium_readl(dev, IC_DATA_CMD);
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if (!i2c_slave_event(dev->slave,
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I2C_SLAVE_WRITE_RECEIVED,
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&val)) {
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dev_vdbg(dev->dev, "Byte %X acked!",
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val);
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}
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phytium_readl(dev, IC_CLR_RD_REQ);
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stat = i2c_phytium_read_clear_intrbits_slave(dev);
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} else {
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phytium_readl(dev, IC_CLR_RD_REQ);
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phytium_readl(dev, IC_CLR_RX_UNDER);
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stat = i2c_phytium_read_clear_intrbits_slave(dev);
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}
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if (!i2c_slave_event(dev->slave,
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I2C_SLAVE_READ_REQUESTED,
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&val))
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phytium_writel(dev, val, IC_DATA_CMD);
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}
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}
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if (stat & IC_INTR_RX_DONE) {
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if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_PROCESSED,
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&val))
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phytium_readl(dev, IC_CLR_RX_DONE);
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i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
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stat = i2c_phytium_read_clear_intrbits_slave(dev);
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return 1;
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}
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if (stat & IC_INTR_RX_FULL) {
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val = phytium_readl(dev, IC_DATA_CMD);
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if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
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&val))
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dev_vdbg(dev->dev, "Byte %X acked!", val);
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} else {
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i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
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stat = i2c_phytium_read_clear_intrbits_slave(dev);
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}
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return 1;
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}
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static irqreturn_t i2c_phytium_isr_slave(int this_irq, void *dev_id)
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{
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struct phytium_i2c_dev *dev = dev_id;
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int ret;
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i2c_phytium_read_clear_intrbits_slave(dev);
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ret = i2c_phytium_irq_handler_slave(dev);
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if (ret > 0)
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complete(&dev->cmd_complete);
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return IRQ_RETVAL(ret);
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}
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static const struct i2c_algorithm i2c_phytium_algo = {
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.functionality = i2c_phytium_func,
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.reg_slave = i2c_phytium_reg_slave,
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.unreg_slave = i2c_phytium_unreg_slave,
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};
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int i2c_phytium_probe_slave(struct phytium_i2c_dev *dev)
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{
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struct i2c_adapter *adap = &dev->adapter;
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int ret;
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init_completion(&dev->cmd_complete);
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dev->init = i2c_phytium_init_slave;
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dev->disable = i2c_phytium_disable;
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dev->disable_int = i2c_phytium_disable_int;
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ret = dev->init(dev);
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if (ret)
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return ret;
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snprintf(adap->name, sizeof(adap->name),
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"Phytium I2C Slave adapter");
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adap->retries = 3;
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adap->algo = &i2c_phytium_algo;
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adap->dev.parent = dev->dev;
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i2c_set_adapdata(adap, dev);
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ret = devm_request_irq(dev->dev, dev->irq, i2c_phytium_isr_slave,
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IRQF_SHARED, dev_name(dev->dev), dev);
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if (ret) {
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dev_err(dev->dev, "failure requesting irq %i: %d\n",
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dev->irq, ret);
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return ret;
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}
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ret = i2c_add_numbered_adapter(adap);
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if (ret)
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dev_err(dev->dev, "failure adding adapter: %d\n", ret);
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return ret;
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}
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EXPORT_SYMBOL_GPL(i2c_phytium_probe_slave);
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