| // SPDX-License-Identifier: GPL-2.0-or-later | 
 | /* | 
 |  * Synopsys DesignWare I2C adapter driver. | 
 |  * | 
 |  * Based on the TI DAVINCI I2C adapter driver. | 
 |  * | 
 |  * Copyright (C) 2006 Texas Instruments. | 
 |  * Copyright (C) 2007 MontaVista Software Inc. | 
 |  * Copyright (C) 2009 Provigent Ltd. | 
 |  */ | 
 | #include <linux/clk.h> | 
 | #include <linux/delay.h> | 
 | #include <linux/export.h> | 
 | #include <linux/errno.h> | 
 | #include <linux/err.h> | 
 | #include <linux/i2c.h> | 
 | #include <linux/interrupt.h> | 
 | #include <linux/io.h> | 
 | #include <linux/module.h> | 
 | #include <linux/pm_runtime.h> | 
 | #include <linux/swab.h> | 
 |  | 
 | #include "i2c-designware-core.h" | 
 |  | 
 | static char *abort_sources[] = { | 
 | 	[ABRT_7B_ADDR_NOACK] = | 
 | 		"slave address not acknowledged (7bit mode)", | 
 | 	[ABRT_10ADDR1_NOACK] = | 
 | 		"first address byte not acknowledged (10bit mode)", | 
 | 	[ABRT_10ADDR2_NOACK] = | 
 | 		"second address byte not acknowledged (10bit mode)", | 
 | 	[ABRT_TXDATA_NOACK] = | 
 | 		"data not acknowledged", | 
 | 	[ABRT_GCALL_NOACK] = | 
 | 		"no acknowledgement for a general call", | 
 | 	[ABRT_GCALL_READ] = | 
 | 		"read after general call", | 
 | 	[ABRT_SBYTE_ACKDET] = | 
 | 		"start byte acknowledged", | 
 | 	[ABRT_SBYTE_NORSTRT] = | 
 | 		"trying to send start byte when restart is disabled", | 
 | 	[ABRT_10B_RD_NORSTRT] = | 
 | 		"trying to read when restart is disabled (10bit mode)", | 
 | 	[ABRT_MASTER_DIS] = | 
 | 		"trying to use disabled adapter", | 
 | 	[ARB_LOST] = | 
 | 		"lost arbitration", | 
 | 	[ABRT_SLAVE_FLUSH_TXFIFO] = | 
 | 		"read command so flush old data in the TX FIFO", | 
 | 	[ABRT_SLAVE_ARBLOST] = | 
 | 		"slave lost the bus while transmitting data to a remote master", | 
 | 	[ABRT_SLAVE_RD_INTX] = | 
 | 		"incorrect slave-transmitter mode configuration", | 
 | }; | 
 |  | 
 | u32 dw_readl(struct dw_i2c_dev *dev, int offset) | 
 | { | 
 | 	u32 value; | 
 |  | 
 | 	if (dev->flags & ACCESS_16BIT) | 
 | 		value = readw_relaxed(dev->base + offset) | | 
 | 			(readw_relaxed(dev->base + offset + 2) << 16); | 
 | 	else | 
 | 		value = readl_relaxed(dev->base + offset); | 
 |  | 
 | 	if (dev->flags & ACCESS_SWAP) | 
 | 		return swab32(value); | 
 | 	else | 
 | 		return value; | 
 | } | 
 |  | 
 | void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset) | 
 | { | 
 | 	if (dev->flags & ACCESS_SWAP) | 
 | 		b = swab32(b); | 
 |  | 
 | 	if (dev->flags & ACCESS_16BIT) { | 
 | 		writew_relaxed((u16)b, dev->base + offset); | 
 | 		writew_relaxed((u16)(b >> 16), dev->base + offset + 2); | 
 | 	} else { | 
 | 		writel_relaxed(b, dev->base + offset); | 
 | 	} | 
 | } | 
 |  | 
 | /** | 
 |  * i2c_dw_set_reg_access() - Set register access flags | 
 |  * @dev: device private data | 
 |  * | 
 |  * Autodetects needed register access mode and sets access flags accordingly. | 
 |  * This must be called before doing any other register access. | 
 |  */ | 
 | int i2c_dw_set_reg_access(struct dw_i2c_dev *dev) | 
 | { | 
 | 	u32 reg; | 
 | 	int ret; | 
 |  | 
 | 	ret = i2c_dw_acquire_lock(dev); | 
 | 	if (ret) | 
 | 		return ret; | 
 |  | 
 | 	reg = dw_readl(dev, DW_IC_COMP_TYPE); | 
 | 	i2c_dw_release_lock(dev); | 
 |  | 
 | 	if (reg == swab32(DW_IC_COMP_TYPE_VALUE)) { | 
 | 		/* Configure register endianess access */ | 
 | 		dev->flags |= ACCESS_SWAP; | 
 | 	} else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { | 
 | 		/* Configure register access mode 16bit */ | 
 | 		dev->flags |= ACCESS_16BIT; | 
 | 	} else if (reg != DW_IC_COMP_TYPE_VALUE) { | 
 | 		dev_err(dev->dev, | 
 | 			"Unknown Synopsys component type: 0x%08x\n", reg); | 
 | 		return -ENODEV; | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset) | 
 | { | 
 | 	/* | 
 | 	 * DesignWare I2C core doesn't seem to have solid strategy to meet | 
 | 	 * the tHD;STA timing spec.  Configuring _HCNT based on tHIGH spec | 
 | 	 * will result in violation of the tHD;STA spec. | 
 | 	 */ | 
 | 	if (cond) | 
 | 		/* | 
 | 		 * Conditional expression: | 
 | 		 * | 
 | 		 *   IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH | 
 | 		 * | 
 | 		 * This is based on the DW manuals, and represents an ideal | 
 | 		 * configuration.  The resulting I2C bus speed will be | 
 | 		 * faster than any of the others. | 
 | 		 * | 
 | 		 * If your hardware is free from tHD;STA issue, try this one. | 
 | 		 */ | 
 | 		return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset; | 
 | 	else | 
 | 		/* | 
 | 		 * Conditional expression: | 
 | 		 * | 
 | 		 *   IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf) | 
 | 		 * | 
 | 		 * This is just experimental rule; the tHD;STA period turned | 
 | 		 * out to be proportinal to (_HCNT + 3).  With this setting, | 
 | 		 * we could meet both tHIGH and tHD;STA timing specs. | 
 | 		 * | 
 | 		 * If unsure, you'd better to take this alternative. | 
 | 		 * | 
 | 		 * The reason why we need to take into account "tf" here, | 
 | 		 * is the same as described in i2c_dw_scl_lcnt(). | 
 | 		 */ | 
 | 		return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000 | 
 | 			- 3 + offset; | 
 | } | 
 |  | 
 | u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset) | 
 | { | 
 | 	/* | 
 | 	 * Conditional expression: | 
 | 	 * | 
 | 	 *   IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf) | 
 | 	 * | 
 | 	 * DW I2C core starts counting the SCL CNTs for the LOW period | 
 | 	 * of the SCL clock (tLOW) as soon as it pulls the SCL line. | 
 | 	 * In order to meet the tLOW timing spec, we need to take into | 
 | 	 * account the fall time of SCL signal (tf).  Default tf value | 
 | 	 * should be 0.3 us, for safety. | 
 | 	 */ | 
 | 	return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset; | 
 | } | 
 |  | 
 | int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev) | 
 | { | 
 | 	u32 reg; | 
 | 	int ret; | 
 |  | 
 | 	ret = i2c_dw_acquire_lock(dev); | 
 | 	if (ret) | 
 | 		return ret; | 
 |  | 
 | 	/* Configure SDA Hold Time if required */ | 
 | 	reg = dw_readl(dev, DW_IC_COMP_VERSION); | 
 | 	if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { | 
 | 		if (!dev->sda_hold_time) { | 
 | 			/* Keep previous hold time setting if no one set it */ | 
 | 			dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD); | 
 | 		} | 
 |  | 
 | 		/* | 
 | 		 * Workaround for avoiding TX arbitration lost in case I2C | 
 | 		 * slave pulls SDA down "too quickly" after falling egde of | 
 | 		 * SCL by enabling non-zero SDA RX hold. Specification says it | 
 | 		 * extends incoming SDA low to high transition while SCL is | 
 | 		 * high but it apprears to help also above issue. | 
 | 		 */ | 
 | 		if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) | 
 | 			dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; | 
 |  | 
 | 		dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n", | 
 | 			dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK, | 
 | 			dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT); | 
 | 	} else if (dev->sda_hold_time) { | 
 | 		dev_warn(dev->dev, | 
 | 			"Hardware too old to adjust SDA hold time.\n"); | 
 | 		dev->sda_hold_time = 0; | 
 | 	} | 
 |  | 
 | 	i2c_dw_release_lock(dev); | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | void __i2c_dw_disable(struct dw_i2c_dev *dev) | 
 | { | 
 | 	int timeout = 100; | 
 |  | 
 | 	do { | 
 | 		__i2c_dw_disable_nowait(dev); | 
 | 		/* | 
 | 		 * The enable status register may be unimplemented, but | 
 | 		 * in that case this test reads zero and exits the loop. | 
 | 		 */ | 
 | 		if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == 0) | 
 | 			return; | 
 |  | 
 | 		/* | 
 | 		 * Wait 10 times the signaling period of the highest I2C | 
 | 		 * transfer supported by the driver (for 400KHz this is | 
 | 		 * 25us) as described in the DesignWare I2C databook. | 
 | 		 */ | 
 | 		usleep_range(25, 250); | 
 | 	} while (timeout--); | 
 |  | 
 | 	dev_warn(dev->dev, "timeout in disabling adapter\n"); | 
 | } | 
 |  | 
 | unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev) | 
 | { | 
 | 	/* | 
 | 	 * Clock is not necessary if we got LCNT/HCNT values directly from | 
 | 	 * the platform code. | 
 | 	 */ | 
 | 	if (WARN_ON_ONCE(!dev->get_clk_rate_khz)) | 
 | 		return 0; | 
 | 	return dev->get_clk_rate_khz(dev); | 
 | } | 
 |  | 
 | int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare) | 
 | { | 
 | 	if (IS_ERR(dev->clk)) | 
 | 		return PTR_ERR(dev->clk); | 
 |  | 
 | 	if (prepare) | 
 | 		return clk_prepare_enable(dev->clk); | 
 |  | 
 | 	clk_disable_unprepare(dev->clk); | 
 | 	return 0; | 
 | } | 
 | EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk); | 
 |  | 
 | int i2c_dw_acquire_lock(struct dw_i2c_dev *dev) | 
 | { | 
 | 	int ret; | 
 |  | 
 | 	if (!dev->acquire_lock) | 
 | 		return 0; | 
 |  | 
 | 	ret = dev->acquire_lock(dev); | 
 | 	if (!ret) | 
 | 		return 0; | 
 |  | 
 | 	dev_err(dev->dev, "couldn't acquire bus ownership\n"); | 
 |  | 
 | 	return ret; | 
 | } | 
 |  | 
 | void i2c_dw_release_lock(struct dw_i2c_dev *dev) | 
 | { | 
 | 	if (dev->release_lock) | 
 | 		dev->release_lock(dev); | 
 | } | 
 |  | 
 | /* | 
 |  * Waiting for bus not busy | 
 |  */ | 
 | int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) | 
 | { | 
 | 	int timeout = TIMEOUT; | 
 |  | 
 | 	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) { | 
 | 		if (timeout <= 0) { | 
 | 			dev_warn(dev->dev, "timeout waiting for bus ready\n"); | 
 | 			i2c_recover_bus(&dev->adapter); | 
 |  | 
 | 			if (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) | 
 | 				return -ETIMEDOUT; | 
 | 			return 0; | 
 | 		} | 
 | 		timeout--; | 
 | 		usleep_range(1000, 1100); | 
 | 	} | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) | 
 | { | 
 | 	unsigned long abort_source = dev->abort_source; | 
 | 	int i; | 
 |  | 
 | 	if (abort_source & DW_IC_TX_ABRT_NOACK) { | 
 | 		for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) | 
 | 			dev_dbg(dev->dev, | 
 | 				"%s: %s\n", __func__, abort_sources[i]); | 
 | 		return -EREMOTEIO; | 
 | 	} | 
 |  | 
 | 	for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) | 
 | 		dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); | 
 |  | 
 | 	if (abort_source & DW_IC_TX_ARB_LOST) | 
 | 		return -EAGAIN; | 
 | 	else if (abort_source & DW_IC_TX_ABRT_GCALL_READ) | 
 | 		return -EINVAL; /* wrong msgs[] data */ | 
 | 	else | 
 | 		return -EIO; | 
 | } | 
 |  | 
 | u32 i2c_dw_func(struct i2c_adapter *adap) | 
 | { | 
 | 	struct dw_i2c_dev *dev = i2c_get_adapdata(adap); | 
 |  | 
 | 	return dev->functionality; | 
 | } | 
 |  | 
 | void i2c_dw_disable(struct dw_i2c_dev *dev) | 
 | { | 
 | 	/* Disable controller */ | 
 | 	__i2c_dw_disable(dev); | 
 |  | 
 | 	/* Disable all interupts */ | 
 | 	dw_writel(dev, 0, DW_IC_INTR_MASK); | 
 | 	dw_readl(dev, DW_IC_CLR_INTR); | 
 | } | 
 |  | 
 | void i2c_dw_disable_int(struct dw_i2c_dev *dev) | 
 | { | 
 | 	dw_writel(dev, 0, DW_IC_INTR_MASK); | 
 | } | 
 |  | 
 | u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev) | 
 | { | 
 | 	return dw_readl(dev, DW_IC_COMP_PARAM_1); | 
 | } | 
 | EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param); | 
 |  | 
 | MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); | 
 | MODULE_LICENSE("GPL"); |