drivers/i2c/busses/i2c-designware-slave.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Synopsys DesignWare I2C adapter driver (slave only).
  *
  * Based on the Synopsys DesignWare I2C adapter driver (master).
  *
  * Copyright (C) 2016 Synopsys Inc.
  */
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>

 #include "i2c-designware-core.h"

 static void i2c_dw_configure_fifo_slave(struct dw_i2c_dev *dev)
 {
 	/* Configure Tx/Rx FIFO threshold levels. */
 	regmap_write(dev->map, DW_IC_TX_TL, 0);
 	regmap_write(dev->map, DW_IC_RX_TL, 0);

 	/* Configure the I2C slave. */
 	regmap_write(dev->map, DW_IC_CON, dev->slave_cfg);
 	regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_SLAVE_MASK);
 }

 /**
  * i2c_dw_init_slave() - Initialize the designware i2c slave hardware
  * @dev: device private data
  *
  * This function configures and enables the I2C in slave mode.
  * This function is called during I2C init function, and in case of timeout at
  * run time.
  */
 static int i2c_dw_init_slave(struct dw_i2c_dev *dev)
 {
 	int ret;

 	ret = i2c_dw_acquire_lock(dev);
 	if (ret)
 		return ret;

 	/* Disable the adapter. */
 	__i2c_dw_disable(dev);

 	/* Write SDA hold time if supported */
 	if (dev->sda_hold_time)
 		regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time);

 	i2c_dw_configure_fifo_slave(dev);
 	i2c_dw_release_lock(dev);

 	return 0;
 }

 static int i2c_dw_reg_slave(struct i2c_client *slave)
 {
 	struct dw_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 DW_apb_i2c responds.
 	 */
 	__i2c_dw_disable_nowait(dev);
 	regmap_write(dev->map, DW_IC_SAR, slave->addr);
 	dev->slave = slave;

 	__i2c_dw_enable(dev);

 	dev->status = 0;

 	return 0;
 }

 static int i2c_dw_unreg_slave(struct i2c_client *slave)
 {
 	struct dw_i2c_dev *dev = i2c_get_adapdata(slave->adapter);

 	regmap_write(dev->map, DW_IC_INTR_MASK, 0);
 	dev->disable(dev);
 	synchronize_irq(dev->irq);
 	dev->slave = NULL;
 	pm_runtime_put(dev->dev);

 	return 0;
 }

 static u32 i2c_dw_read_clear_intrbits_slave(struct dw_i2c_dev *dev)
 {
 	unsigned int stat, dummy;

 	/*
 	 * The IC_INTR_STAT register just indicates "enabled" interrupts.
 	 * The unmasked raw version of interrupt status bits is available
 	 * in the IC_RAW_INTR_STAT register.
 	 *
 	 * That is,
 	 *   stat = readl(IC_INTR_STAT);
 	 * equals to,
 	 *   stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK);
 	 *
 	 * The raw version might be useful for debugging purposes.
 	 */
 	regmap_read(dev->map, DW_IC_INTR_STAT, &stat);

 	/*
 	 * Do not use the IC_CLR_INTR register to clear interrupts, or
 	 * you'll miss some interrupts, triggered during the period from
 	 * readl(IC_INTR_STAT) to readl(IC_CLR_INTR).
 	 *
 	 * Instead, use the separately-prepared IC_CLR_* registers.
 	 */
 	if (stat & DW_IC_INTR_TX_ABRT)
 		regmap_read(dev->map, DW_IC_CLR_TX_ABRT, &dummy);
 	if (stat & DW_IC_INTR_RX_UNDER)
 		regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &dummy);
 	if (stat & DW_IC_INTR_RX_OVER)
 		regmap_read(dev->map, DW_IC_CLR_RX_OVER, &dummy);
 	if (stat & DW_IC_INTR_TX_OVER)
 		regmap_read(dev->map, DW_IC_CLR_TX_OVER, &dummy);
 	if (stat & DW_IC_INTR_RX_DONE)
 		regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
 	if (stat & DW_IC_INTR_ACTIVITY)
 		regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
 	if (stat & DW_IC_INTR_STOP_DET)
 		regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
 	if (stat & DW_IC_INTR_START_DET)
 		regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
 	if (stat & DW_IC_INTR_GEN_CALL)
 		regmap_read(dev->map, DW_IC_CLR_GEN_CALL, &dummy);

 	return stat;
 }

 /*
  * Interrupt service routine. This gets called whenever an I2C slave interrupt
  * occurs.
  */
 static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
 {
 	struct dw_i2c_dev *dev = dev_id;
 	unsigned int raw_stat, stat, enabled, tmp;
 	u8 val = 0, slave_activity;

 	regmap_read(dev->map, DW_IC_ENABLE, &enabled);
 	regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
 	regmap_read(dev->map, DW_IC_STATUS, &tmp);
 	slave_activity = ((tmp & DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);

 	if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
 		return IRQ_NONE;

 	stat = i2c_dw_read_clear_intrbits_slave(dev);
 	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 & DW_IC_INTR_RX_FULL) {
 		if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
 			dev->status |= STATUS_WRITE_IN_PROGRESS;
 			dev->status &= ~STATUS_READ_IN_PROGRESS;
 			i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED,
 					&val);
 		}

 		do {
 			regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
 			val = tmp;
 			i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
 					&val);
 			regmap_read(dev->map, DW_IC_STATUS, &tmp);
 		} while (tmp & DW_IC_STATUS_RFNE);
 	}

 	if (stat & DW_IC_INTR_RD_REQ) {
 		if (slave_activity) {
 			regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);

 			if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
 				i2c_slave_event(dev->slave,
 						I2C_SLAVE_READ_REQUESTED,
 						&val);
 				dev->status |= STATUS_READ_IN_PROGRESS;
 				dev->status &= ~STATUS_WRITE_IN_PROGRESS;
 			} else {
 				i2c_slave_event(dev->slave,
 						I2C_SLAVE_READ_PROCESSED,
 						&val);
 			}
 			regmap_write(dev->map, DW_IC_DATA_CMD, val);
 		}
 	}

 	if (stat & DW_IC_INTR_STOP_DET)
 		i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);

 	return IRQ_HANDLED;
 }

 static const struct i2c_algorithm i2c_dw_algo = {
 	.functionality = i2c_dw_func,
 	.reg_slave = i2c_dw_reg_slave,
 	.unreg_slave = i2c_dw_unreg_slave,
 };

 void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
 {
 	dev->functionality = I2C_FUNC_SLAVE | DW_IC_DEFAULT_FUNCTIONALITY;

 	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
 			 DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED;

 	dev->mode = DW_IC_SLAVE;
 }
 EXPORT_SYMBOL_GPL(i2c_dw_configure_slave);

 int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
 {
 	struct i2c_adapter *adap = &dev->adapter;
 	int ret;

 	dev->init = i2c_dw_init_slave;
 	dev->disable = i2c_dw_disable;

 	ret = i2c_dw_init_regmap(dev);
 	if (ret)
 		return ret;

 	ret = i2c_dw_set_sda_hold(dev);
 	if (ret)
 		return ret;

 	ret = i2c_dw_set_fifo_size(dev);
 	if (ret)
 		return ret;

 	ret = dev->init(dev);
 	if (ret)
 		return ret;

 	snprintf(adap->name, sizeof(adap->name),
 		 "Synopsys DesignWare I2C Slave adapter");
 	adap->retries = 3;
 	adap->algo = &i2c_dw_algo;
 	adap->dev.parent = dev->dev;
 	i2c_set_adapdata(adap, dev);

 	ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_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_dw_probe_slave);

 MODULE_AUTHOR("Luis Oliveira <lolivei@synopsys.com>");
 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus slave adapter");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Synopsys DesignWare I2C adapter driver (slave only).
	*
	* Based on the Synopsys DesignWare I2C adapter driver (master).
	*
	* Copyright (C) 2016 Synopsys Inc.
	*/
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/errno.h>
	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/pm_runtime.h>
	#include <linux/regmap.h>

	#include "i2c-designware-core.h"

	static void i2c_dw_configure_fifo_slave(struct dw_i2c_dev *dev)
	{
	/* Configure Tx/Rx FIFO threshold levels. */
	regmap_write(dev->map, DW_IC_TX_TL, 0);
	regmap_write(dev->map, DW_IC_RX_TL, 0);

	/* Configure the I2C slave. */
	regmap_write(dev->map, DW_IC_CON, dev->slave_cfg);
	regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_SLAVE_MASK);
	}

	/**
	* i2c_dw_init_slave() - Initialize the designware i2c slave hardware
	* @dev: device private data
	*
	* This function configures and enables the I2C in slave mode.
	* This function is called during I2C init function, and in case of timeout at
	* run time.
	*/
	static int i2c_dw_init_slave(struct dw_i2c_dev *dev)
	{
	int ret;

	ret = i2c_dw_acquire_lock(dev);
	if (ret)
	return ret;

	/* Disable the adapter. */
	__i2c_dw_disable(dev);

	/* Write SDA hold time if supported */
	if (dev->sda_hold_time)
	regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time);

	i2c_dw_configure_fifo_slave(dev);
	i2c_dw_release_lock(dev);

	return 0;
	}

	static int i2c_dw_reg_slave(struct i2c_client *slave)
	{
	struct dw_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 DW_apb_i2c responds.
	*/
	__i2c_dw_disable_nowait(dev);
	regmap_write(dev->map, DW_IC_SAR, slave->addr);
	dev->slave = slave;

	__i2c_dw_enable(dev);

	dev->status = 0;

	return 0;
	}

	static int i2c_dw_unreg_slave(struct i2c_client *slave)
	{
	struct dw_i2c_dev *dev = i2c_get_adapdata(slave->adapter);

	regmap_write(dev->map, DW_IC_INTR_MASK, 0);
	dev->disable(dev);
	synchronize_irq(dev->irq);
	dev->slave = NULL;
	pm_runtime_put(dev->dev);

	return 0;
	}

	static u32 i2c_dw_read_clear_intrbits_slave(struct dw_i2c_dev *dev)
	{
	unsigned int stat, dummy;

	/*
	* The IC_INTR_STAT register just indicates "enabled" interrupts.
	* The unmasked raw version of interrupt status bits is available
	* in the IC_RAW_INTR_STAT register.
	*
	* That is,
	* stat = readl(IC_INTR_STAT);
	* equals to,
	* stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK);
	*
	* The raw version might be useful for debugging purposes.
	*/
	regmap_read(dev->map, DW_IC_INTR_STAT, &stat);

	/*
	* Do not use the IC_CLR_INTR register to clear interrupts, or
	* you'll miss some interrupts, triggered during the period from
	* readl(IC_INTR_STAT) to readl(IC_CLR_INTR).
	*
	* Instead, use the separately-prepared IC_CLR_* registers.
	*/
	if (stat & DW_IC_INTR_TX_ABRT)
	regmap_read(dev->map, DW_IC_CLR_TX_ABRT, &dummy);
	if (stat & DW_IC_INTR_RX_UNDER)
	regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &dummy);
	if (stat & DW_IC_INTR_RX_OVER)
	regmap_read(dev->map, DW_IC_CLR_RX_OVER, &dummy);
	if (stat & DW_IC_INTR_TX_OVER)
	regmap_read(dev->map, DW_IC_CLR_TX_OVER, &dummy);
	if (stat & DW_IC_INTR_RX_DONE)
	regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
	if (stat & DW_IC_INTR_ACTIVITY)
	regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
	if (stat & DW_IC_INTR_STOP_DET)
	regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
	if (stat & DW_IC_INTR_START_DET)
	regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
	if (stat & DW_IC_INTR_GEN_CALL)
	regmap_read(dev->map, DW_IC_CLR_GEN_CALL, &dummy);

	return stat;
	}

	/*
	* Interrupt service routine. This gets called whenever an I2C slave interrupt
	* occurs.
	*/
	static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
	{
	struct dw_i2c_dev *dev = dev_id;
	unsigned int raw_stat, stat, enabled, tmp;
	u8 val = 0, slave_activity;

	regmap_read(dev->map, DW_IC_ENABLE, &enabled);
	regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
	regmap_read(dev->map, DW_IC_STATUS, &tmp);
	slave_activity = ((tmp & DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);

	if (!enabled \|\| !(raw_stat & ~DW_IC_INTR_ACTIVITY) \|\| !dev->slave)
	return IRQ_NONE;

	stat = i2c_dw_read_clear_intrbits_slave(dev);
	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 & DW_IC_INTR_RX_FULL) {
	if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
	dev->status \|= STATUS_WRITE_IN_PROGRESS;
	dev->status &= ~STATUS_READ_IN_PROGRESS;
	i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED,
	&val);
	}

	do {
	regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
	val = tmp;
	i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
	&val);
	regmap_read(dev->map, DW_IC_STATUS, &tmp);
	} while (tmp & DW_IC_STATUS_RFNE);
	}

	if (stat & DW_IC_INTR_RD_REQ) {
	if (slave_activity) {
	regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);

	if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
	i2c_slave_event(dev->slave,
	I2C_SLAVE_READ_REQUESTED,
	&val);
	dev->status \|= STATUS_READ_IN_PROGRESS;
	dev->status &= ~STATUS_WRITE_IN_PROGRESS;
	} else {
	i2c_slave_event(dev->slave,
	I2C_SLAVE_READ_PROCESSED,
	&val);
	}
	regmap_write(dev->map, DW_IC_DATA_CMD, val);
	}
	}

	if (stat & DW_IC_INTR_STOP_DET)
	i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);

	return IRQ_HANDLED;
	}

	static const struct i2c_algorithm i2c_dw_algo = {
	.functionality = i2c_dw_func,
	.reg_slave = i2c_dw_reg_slave,
	.unreg_slave = i2c_dw_unreg_slave,
	};

	void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
	{
	dev->functionality = I2C_FUNC_SLAVE \| DW_IC_DEFAULT_FUNCTIONALITY;

	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL \|
	DW_IC_CON_RESTART_EN \| DW_IC_CON_STOP_DET_IFADDRESSED;

	dev->mode = DW_IC_SLAVE;
	}
	EXPORT_SYMBOL_GPL(i2c_dw_configure_slave);

	int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
	{
	struct i2c_adapter *adap = &dev->adapter;
	int ret;

	dev->init = i2c_dw_init_slave;
	dev->disable = i2c_dw_disable;

	ret = i2c_dw_init_regmap(dev);
	if (ret)
	return ret;

	ret = i2c_dw_set_sda_hold(dev);
	if (ret)
	return ret;

	ret = i2c_dw_set_fifo_size(dev);
	if (ret)
	return ret;

	ret = dev->init(dev);
	if (ret)
	return ret;

	snprintf(adap->name, sizeof(adap->name),
	"Synopsys DesignWare I2C Slave adapter");
	adap->retries = 3;
	adap->algo = &i2c_dw_algo;
	adap->dev.parent = dev->dev;
	i2c_set_adapdata(adap, dev);

	ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_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_dw_probe_slave);

	MODULE_AUTHOR("Luis Oliveira <lolivei@synopsys.com>");
	MODULE_DESCRIPTION("Synopsys DesignWare I2C bus slave adapter");
	MODULE_LICENSE("GPL v2");