[PATCH v12 0/2] i2c: designware: add I2C SLAVE support

[PATCH v12 0/2] i2c: designware: add I2C SLAVE support

[Luis Oliveira]

This patches follows the merged patchset that refactors I2C Designware and
enables it to have I2C support.

The patch 1 adds the necessary functions to give the ability to be a SLAVE
to the controller and for that changes also had to be made in the 
Makefile and Kconfig.
The patch 2 enables the SLAVE mode to be detected by the platform module.

The functionality was tested using the hardware independent slave-eeprom
driver based on top of i2c/for-next. The tree I used can be found here:

https://git.kernel.org/cgit/linux/kernel/git/wsa/linux.git/log/?h=i2c/for-next

Luis Oliveira (2):
  i2c: designware: add SLAVE mode functions
  i2c: designware: enable SLAVE in platform module

 drivers/i2c/busses/Kconfig                  |  14 +-
 drivers/i2c/busses/Makefile                 |   3 +
 drivers/i2c/busses/i2c-designware-common.c  |   6 +
 drivers/i2c/busses/i2c-designware-core.h    |   4 +
 drivers/i2c/busses/i2c-designware-platdrv.c |  41 ++-
 drivers/i2c/busses/i2c-designware-slave.c   | 395 ++++++++++++++++++++++++++++
 6 files changed, 457 insertions(+), 6 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-designware-slave.c

-- 
2.13.0

[PATCH v12 0/2] i2c: designware: add I2C SLAVE support

[Luis Oliveira]

This patches follows the merged patchset that refactors I2C Designware and
enables it to have I2C support.

The patch 1 adds the necessary functions to give the ability to be a SLAVE
to the controller and for that changes also had to be made in the 
Makefile and Kconfig.
The patch 2 enables the SLAVE mode to be detected by the platform module.

The functionality was tested using the hardware independent slave-eeprom
driver based on top of i2c/for-next. The tree I used can be found here:

https://git.kernel.org/cgit/linux/kernel/git/wsa/linux.git/log/?h=i2c/for-next

Luis Oliveira (2):
  i2c: designware: add SLAVE mode functions
  i2c: designware: enable SLAVE in platform module

 drivers/i2c/busses/Kconfig                  |  14 +-
 drivers/i2c/busses/Makefile                 |   3 +
 drivers/i2c/busses/i2c-designware-common.c  |   6 +
 drivers/i2c/busses/i2c-designware-core.h    |   4 +
 drivers/i2c/busses/i2c-designware-platdrv.c |  41 ++-
 drivers/i2c/busses/i2c-designware-slave.c   | 395 ++++++++++++++++++++++++++++
 6 files changed, 457 insertions(+), 6 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-designware-slave.c

-- 
2.13.0


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[PATCH v12 1/2] i2c: designware: add SLAVE mode functions

[Luis Oliveira]

- Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
- Slave functions added to core library file
- Slave abort sources added to common source file
- New driver: i2c-designware-slave added
- Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
  when supported by the architecture.

All the SLAVE flow is added but it is not enabled via platform
driver.

Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
---
V11-v12
- Changed ifdef condition in the Makefile fixed Kbuild error

 drivers/i2c/busses/Kconfig                 |  14 +-
 drivers/i2c/busses/Makefile                |   3 +
 drivers/i2c/busses/i2c-designware-common.c |   6 +
 drivers/i2c/busses/i2c-designware-core.h   |   2 +
 drivers/i2c/busses/i2c-designware-slave.c  | 395 +++++++++++++++++++++++++++++
 5 files changed, 419 insertions(+), 1 deletion(-)
 create mode 100644 drivers/i2c/busses/i2c-designware-slave.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index ed7106e48ba4..ed92bf560825 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -473,14 +473,26 @@ config I2C_DESIGNWARE_CORE
 config I2C_DESIGNWARE_PLATFORM
 	tristate "Synopsys DesignWare Platform"
 	select I2C_DESIGNWARE_CORE
+	select I2C_DESIGNWARE_SLAVE
 	depends on (ACPI && COMMON_CLK) || !ACPI
 	help
 	  If you say yes to this option, support will be included for the
-	  Synopsys DesignWare I2C adapter. Only master mode is supported.
+	  Synopsys DesignWare I2C adapter.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-designware-platform.
 
+config I2C_DESIGNWARE_SLAVE
+	bool "Synopsys DesignWare Slave"
+	select I2C_SLAVE
+	depends on I2C_DESIGNWARE_PLATFORM
+	help
+	  If you say yes to this option, support will be included for the
+	  Synopsys DesignWare I2C slave adapter.
+
+	  This is not a standalone module, this module compiles together with
+	  i2c-designware-core.
+
 config I2C_DESIGNWARE_PCI
 	tristate "Synopsys DesignWare PCI"
 	depends on PCI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index c89a4314c563..d630a6cbafeb 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -41,6 +41,9 @@ obj-$(CONFIG_I2C_CPM)		+= i2c-cpm.o
 obj-$(CONFIG_I2C_DAVINCI)	+= i2c-davinci.o
 obj-$(CONFIG_I2C_DESIGNWARE_CORE)	+= i2c-designware-core.o
 i2c-designware-core-objs := i2c-designware-common.o i2c-designware-master.o
+ifeq ($(CONFIG_I2C_DESIGNWARE_SLAVE),y)
+i2c-designware-core-objs += i2c-designware-slave.o
+endif
 obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM)	+= i2c-designware-platform.o
 i2c-designware-platform-objs := i2c-designware-platdrv.o
 i2c-designware-platform-$(CONFIG_I2C_DESIGNWARE_BAYTRAIL) += i2c-designware-baytrail.o
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 0d0ccb73f0e6..d1a69372432f 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -56,6 +56,12 @@ static char *abort_sources[] = {
 		"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)
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 76807eafda53..64a39a983410 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -305,9 +305,11 @@ u32 i2c_dw_func(struct i2c_adapter *adap);
 void i2c_dw_disable(struct dw_i2c_dev *dev);
 void i2c_dw_disable_int(struct dw_i2c_dev *dev);
 int i2c_dw_init(struct dw_i2c_dev *dev);
+int i2c_dw_init_slave(struct dw_i2c_dev *dev);
 
 extern u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev);
 extern int i2c_dw_probe(struct dw_i2c_dev *dev);
+extern int i2c_dw_probe_slave(struct dw_i2c_dev *dev);
 
 #if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL)
 extern int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev);
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
new file mode 100644
index 000000000000..1f6a13f69d0c
--- /dev/null
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -0,0 +1,395 @@
+/*
+ * Synopsys DesignWare I2C adapter driver (slave only).
+ *
+ * Based on the Synopsys DesignWare I2C adapter driver (master).
+ *
+ * Copyright (C) 2016 Synopsys Inc.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * ----------------------------------------------------------------------------
+ *
+ */
+#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 "i2c-designware-core.h"
+
+static void i2c_dw_configure_fifo_slave(struct dw_i2c_dev *dev)
+{
+	/* Configure Tx/Rx FIFO threshold levels. */
+	dw_writel(dev, 0, DW_IC_TX_TL);
+	dw_writel(dev, 0, DW_IC_RX_TL);
+
+	/* Configure the I2C slave. */
+	dw_writel(dev, dev->slave_cfg, DW_IC_CON);
+	dw_writel(dev, DW_IC_INTR_SLAVE_MASK, DW_IC_INTR_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.
+ */
+int i2c_dw_init_slave(struct dw_i2c_dev *dev)
+{
+	u32 sda_falling_time, scl_falling_time;
+	u32 reg, comp_param1;
+	u32 hcnt, lcnt;
+	int ret;
+
+	ret = i2c_dw_acquire_lock(dev);
+	if (ret)
+		return ret;
+
+	reg = dw_readl(dev, DW_IC_COMP_TYPE);
+	if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
+		/* Configure register endianness 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);
+		i2c_dw_release_lock(dev);
+		return -ENODEV;
+	}
+
+	comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1);
+
+	/* Disable the adapter. */
+	__i2c_dw_enable_and_wait(dev, false);
+
+	/* Set standard and fast speed deviders for high/low periods. */
+	sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
+	scl_falling_time = dev->scl_falling_time ?: 300; /* ns */
+
+	/* Set SCL timing parameters for standard-mode. */
+	if (dev->ss_hcnt && dev->ss_lcnt) {
+		hcnt = dev->ss_hcnt;
+		lcnt = dev->ss_lcnt;
+	} else {
+		hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
+				       4000,	/* tHD;STA = tHIGH = 4.0 us */
+				       sda_falling_time,
+				       0,	/* 0: DW default, 1: Ideal */
+				       0);	/* No offset */
+		lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
+				       4700,	/* tLOW = 4.7 us */
+				       scl_falling_time,
+				       0);	/* No offset */
+	}
+	dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
+	dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
+	dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+
+	/* Set SCL timing parameters for fast-mode or fast-mode plus. */
+	if ((dev->clk_freq == 1000000) && dev->fp_hcnt && dev->fp_lcnt) {
+		hcnt = dev->fp_hcnt;
+		lcnt = dev->fp_lcnt;
+	} else if (dev->fs_hcnt && dev->fs_lcnt) {
+		hcnt = dev->fs_hcnt;
+		lcnt = dev->fs_lcnt;
+	} else {
+		hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
+				       600,	/* tHD;STA = tHIGH = 0.6 us */
+				       sda_falling_time,
+				       0,	/* 0: DW default, 1: Ideal */
+				       0);	/* No offset */
+		lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
+				       1300,	/* tLOW = 1.3 us */
+				       scl_falling_time,
+				       0);	/* No offset */
+	}
+	dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
+	dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
+	dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+
+	if ((dev->slave_cfg & DW_IC_CON_SPEED_MASK) ==
+		DW_IC_CON_SPEED_HIGH) {
+		if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
+			!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) {
+			dev_err(dev->dev, "High Speed not supported!\n");
+			dev->slave_cfg &= ~DW_IC_CON_SPEED_MASK;
+			dev->slave_cfg |= DW_IC_CON_SPEED_FAST;
+		} else if (dev->hs_hcnt && dev->hs_lcnt) {
+			hcnt = dev->hs_hcnt;
+			lcnt = dev->hs_lcnt;
+			dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT);
+			dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT);
+			dev_dbg(dev->dev, "HighSpeed-mode HCNT:LCNT = %d:%d\n",
+				hcnt, lcnt);
+		}
+	}
+
+	/* 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;
+		dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
+	} else {
+		dev_warn(dev->dev,
+			 "Hardware too old to adjust SDA hold time.\n");
+	}
+
+	i2c_dw_configure_fifo_slave(dev);
+	i2c_dw_release_lock(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_init_slave);
+
+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;
+	/*
+	 * Set slave address in the IC_SAR register,
+	 * the address to which the DW_apb_i2c responds.
+	 */
+	__i2c_dw_enable(dev, false);
+	dw_writel(dev, slave->addr, DW_IC_SAR);
+	dev->slave = slave;
+
+	__i2c_dw_enable(dev, true);
+
+	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_dw_unreg_slave(struct i2c_client *slave)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(slave->adapter);
+
+	dev->disable_int(dev);
+	dev->disable(dev);
+	dev->slave = NULL;
+
+	return 0;
+}
+
+static u32 i2c_dw_read_clear_intrbits_slave(struct dw_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 = dw_readl(IC_INTR_STAT);
+	 * equals to,
+	 *   stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
+	 *
+	 * The raw version might be useful for debugging purposes.
+	 */
+	stat = dw_readl(dev, DW_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
+	 * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
+	 *
+	 * Instead, use the separately-prepared IC_CLR_* registers.
+	 */
+	if (stat & DW_IC_INTR_TX_ABRT)
+		dw_readl(dev, DW_IC_CLR_TX_ABRT);
+	if (stat & DW_IC_INTR_RX_UNDER)
+		dw_readl(dev, DW_IC_CLR_RX_UNDER);
+	if (stat & DW_IC_INTR_RX_OVER)
+		dw_readl(dev, DW_IC_CLR_RX_OVER);
+	if (stat & DW_IC_INTR_TX_OVER)
+		dw_readl(dev, DW_IC_CLR_TX_OVER);
+	if (stat & DW_IC_INTR_RX_DONE)
+		dw_readl(dev, DW_IC_CLR_RX_DONE);
+	if (stat & DW_IC_INTR_ACTIVITY)
+		dw_readl(dev, DW_IC_CLR_ACTIVITY);
+	if (stat & DW_IC_INTR_STOP_DET)
+		dw_readl(dev, DW_IC_CLR_STOP_DET);
+	if (stat & DW_IC_INTR_START_DET)
+		dw_readl(dev, DW_IC_CLR_START_DET);
+	if (stat & DW_IC_INTR_GEN_CALL)
+		dw_readl(dev, DW_IC_CLR_GEN_CALL);
+
+	return stat;
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C slave interrupt
+ * occurs.
+ */
+
+static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
+{
+	u32 raw_stat, stat, enabled;
+	u8 val, slave_activity;
+
+	stat = dw_readl(dev, DW_IC_INTR_STAT);
+	enabled = dw_readl(dev, DW_IC_ENABLE);
+	raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
+	slave_activity = ((dw_readl(dev, DW_IC_STATUS) &
+		DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);
+
+	if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY))
+		return 0;
+
+	dev_dbg(dev->dev,
+		"%#x STAUTS SLAVE_ACTTVITY=%#x : RAW_INTR_STAT=%#x"
+		" : INTR_STAT=%#x\n",
+		enabled, slave_activity, raw_stat, stat);
+
+	if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
+		i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
+
+	if (stat & DW_IC_INTR_RD_REQ) {
+		if (slave_activity) {
+			if (stat & DW_IC_INTR_RX_FULL) {
+				val = dw_readl(dev, DW_IC_DATA_CMD);
+
+				if (!i2c_slave_event(dev->slave,
+						     I2C_SLAVE_WRITE_RECEIVED,
+						     &val)) {
+					dev_vdbg(dev->dev, "Byte %X acked!",
+						 val);
+				}
+				dw_readl(dev, DW_IC_CLR_RD_REQ);
+				stat = i2c_dw_read_clear_intrbits_slave(dev);
+			} else {
+				dw_readl(dev, DW_IC_CLR_RD_REQ);
+				dw_readl(dev, DW_IC_CLR_RX_UNDER);
+				stat = i2c_dw_read_clear_intrbits_slave(dev);
+			}
+			if (!i2c_slave_event(dev->slave,
+					     I2C_SLAVE_READ_REQUESTED,
+					     &val))
+				dw_writel(dev, val, DW_IC_DATA_CMD);
+		}
+	}
+
+	if (stat & DW_IC_INTR_RX_DONE) {
+		if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_PROCESSED,
+				     &val))
+			dw_readl(dev, DW_IC_CLR_RX_DONE);
+
+		i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
+		stat = i2c_dw_read_clear_intrbits_slave(dev);
+		return 1;
+	}
+
+	if (stat & DW_IC_INTR_RX_FULL) {
+		val = dw_readl(dev, DW_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_dw_read_clear_intrbits_slave(dev);
+	}
+
+	return 1;
+}
+
+static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
+{
+	struct dw_i2c_dev *dev = dev_id;
+	int ret;
+
+	i2c_dw_read_clear_intrbits_slave(dev);
+	ret = i2c_dw_irq_handler_slave(dev);
+	if (ret > 0)
+		complete(&dev->cmd_complete);
+
+	return IRQ_RETVAL(ret);
+}
+
+static struct i2c_algorithm i2c_dw_algo = {
+	.functionality = i2c_dw_func,
+	.reg_slave = i2c_dw_reg_slave,
+	.unreg_slave = i2c_dw_unreg_slave,
+};
+
+int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
+{
+	struct i2c_adapter *adap = &dev->adapter;
+	int ret;
+
+	init_completion(&dev->cmd_complete);
+
+	dev->init = i2c_dw_init_slave;
+	dev->disable = i2c_dw_disable;
+	dev->disable_int = i2c_dw_disable_int;
+
+	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);
+	pm_runtime_put_noidle(dev->dev);
+
+	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");
-- 
2.13.0

[PATCH v12 2/2] i2c: designware: enable SLAVE in platform module

[Luis Oliveira]

- Slave mode selected in platform module if the support is detected in
  the DT.

Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
V11-V12
- no changes

 drivers/i2c/busses/i2c-designware-core.h    |  2 ++
 drivers/i2c/busses/i2c-designware-platdrv.c | 41 +++++++++++++++++++++++++----
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 64a39a983410..7bfbcc62f6c5 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -228,6 +228,7 @@
  * @disable: function to disable the controller
  * @disable_int: function to disable all interrupts
  * @init: function to initialize the I2C hardware
+ * @mode: operation mode - DW_IC_MASTER or DW_IC_SLAVE
  *
  * HCNT and LCNT parameters can be used if the platform knows more accurate
  * values than the one computed based only on the input clock frequency.
@@ -282,6 +283,7 @@ struct dw_i2c_dev {
 	void			(*disable)(struct dw_i2c_dev *dev);
 	void			(*disable_int)(struct dw_i2c_dev *dev);
 	int			(*init)(struct dw_i2c_dev *dev);
+	int			mode;
 };
 
 #define ACCESS_SWAP		0x00000001
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 1f38c807be5f..2ea6d0d25a01 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -1,5 +1,5 @@
 /*
- * Synopsys DesignWare I2C adapter driver (master only).
+ * Synopsys DesignWare I2C adapter driver.
  *
  * Based on the TI DAVINCI I2C adapter driver.
  *
@@ -174,9 +174,13 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 
 static void i2c_dw_configure_master(struct dw_i2c_dev *dev)
 {
+	dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
+
 	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
 			  DW_IC_CON_RESTART_EN;
 
+	dev->mode = DW_IC_MASTER;
+
 	switch (dev->clk_freq) {
 	case 100000:
 		dev->master_cfg |= DW_IC_CON_SPEED_STD;
@@ -189,6 +193,28 @@ static void i2c_dw_configure_master(struct dw_i2c_dev *dev)
 	}
 }
 
+static 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 |
+			 DW_IC_CON_SPEED_FAST;
+
+	dev->mode = DW_IC_SLAVE;
+
+	switch (dev->clk_freq) {
+	case 100000:
+		dev->slave_cfg |= DW_IC_CON_SPEED_STD;
+		break;
+	case 3400000:
+		dev->slave_cfg |= DW_IC_CON_SPEED_HIGH;
+		break;
+	default:
+		dev->slave_cfg |= DW_IC_CON_SPEED_FAST;
+	}
+}
+
 static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
 {
 	if (IS_ERR(i_dev->clk))
@@ -302,9 +328,10 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	if (ret)
 		goto exit_reset;
 
-	dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
-
-	i2c_dw_configure_master(dev);
+	if (i2c_detect_slave_mode(&pdev->dev))
+		i2c_dw_configure_slave(dev);
+	else
+		i2c_dw_configure_master(dev);
 
 	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (!i2c_dw_plat_prepare_clk(dev, true)) {
@@ -333,7 +360,11 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 		pm_runtime_enable(&pdev->dev);
 	}
 
-	ret = i2c_dw_probe(dev);
+	if (dev->mode == DW_IC_SLAVE)
+		ret = i2c_dw_probe_slave(dev);
+	else
+		ret = i2c_dw_probe(dev);
+
 	if (ret)
 		goto exit_probe;
 
-- 
2.13.0

Re: [PATCH v12 2/2] i2c: designware: enable SLAVE in platform module

[Jarkko Nikula]

On 06/22/2017 01:17 PM, Luis Oliveira wrote:
> - Slave mode selected in platform module if the support is detected in
>   the DT.
>
> Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> ---
> V11-V12
> - no changes
>
>  drivers/i2c/busses/i2c-designware-core.h    |  2 ++
>  drivers/i2c/busses/i2c-designware-platdrv.c | 41 +++++++++++++++++++++++++----
>  2 files changed, 38 insertions(+), 5 deletions(-)
>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>

Re: [PATCH v12 1/2] i2c: designware: add SLAVE mode functions

[Andy Shevchenko]

On Thu, 2017-06-22 at 11:17 +0100, Luis Oliveira wrote:
> - Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
> - Slave functions added to core library file
> - Slave abort sources added to common source file
> - New driver: i2c-designware-slave added
> - Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
>   when supported by the architecture.
> 
> All the SLAVE flow is added but it is not enabled via platform
> driver.

There are couple of nits, otherwise I'm okay with the patch.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> V11-v12
> - Changed ifdef condition in the Makefile fixed Kbuild error

+ rebased on top of latest i2c-next (drop applied patches effectively)

> +static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
> +{
> 

> +	dev_dbg(dev->dev,

> +		"%#x STAUTS SLAVE_ACTTVITY=%#x : RAW_INTR_STAT=%#x"
> +		" : INTR_STAT=%#x\n",

Don't split string literals.

> +		enabled, slave_activity, raw_stat, stat);


> +					dev_vdbg(dev->dev, "Byte %X
> acked!",
> +						 val);

I'm not sure it's any helpful.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

Re: [PATCH v12 1/2] i2c: designware: add SLAVE mode functions

[Jarkko Nikula]

On 06/22/2017 01:17 PM, Luis Oliveira wrote:
> - Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
> - Slave functions added to core library file
> - Slave abort sources added to common source file
> - New driver: i2c-designware-slave added
> - Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
>   when supported by the architecture.
>
> All the SLAVE flow is added but it is not enabled via platform
> driver.
>
> Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
> ---
> V11-v12
> - Changed ifdef condition in the Makefile fixed Kbuild error
>
>  drivers/i2c/busses/Kconfig                 |  14 +-
>  drivers/i2c/busses/Makefile                |   3 +
>  drivers/i2c/busses/i2c-designware-common.c |   6 +
>  drivers/i2c/busses/i2c-designware-core.h   |   2 +
>  drivers/i2c/busses/i2c-designware-slave.c  | 395 +++++++++++++++++++++++++++++
>  5 files changed, 419 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/i2c/busses/i2c-designware-slave.c
>
...
> +static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
> +{
> +	u32 raw_stat, stat, enabled;
> +	u8 val, slave_activity;
> +
> +	stat = dw_readl(dev, DW_IC_INTR_STAT);
> +	enabled = dw_readl(dev, DW_IC_ENABLE);
> +	raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
> +	slave_activity = ((dw_readl(dev, DW_IC_STATUS) &
> +		DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);
> +
> +	if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY))
> +		return 0;
> +
> +	dev_dbg(dev->dev,
> +		"%#x STAUTS SLAVE_ACTTVITY=%#x : RAW_INTR_STAT=%#x"
> +		" : INTR_STAT=%#x\n",
> +		enabled, slave_activity, raw_stat, stat);
> +

Minor notes:
- Strings that are printed should fit in single line for making easier 
to grep them from sources. Maybe not all of those variables are not 
necessary in this debug print (e.g. are we interested other than bit 0 
in DW_IC_ENABLE and line above already returns if it reads zero).
- Typos "STAUTS SLAVE_ACTTVITY".

You may add my acked by if you want to send another version or I'm fine 
with incremental patch also.

Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>

Re: [PATCH v12 1/2] i2c: designware: add SLAVE mode functions

[Jarkko Nikula]

On 06/22/2017 01:17 PM, Luis Oliveira wrote:
> - Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
> - Slave functions added to core library file
> - Slave abort sources added to common source file
> - New driver: i2c-designware-slave added
> - Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
>   when supported by the architecture.
>
> All the SLAVE flow is added but it is not enabled via platform
> driver.
>
> Signed-off-by: Luis Oliveira <lolivei-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
> ---
> V11-v12
> - Changed ifdef condition in the Makefile fixed Kbuild error
>
>  drivers/i2c/busses/Kconfig                 |  14 +-
>  drivers/i2c/busses/Makefile                |   3 +
>  drivers/i2c/busses/i2c-designware-common.c |   6 +
>  drivers/i2c/busses/i2c-designware-core.h   |   2 +
>  drivers/i2c/busses/i2c-designware-slave.c  | 395 +++++++++++++++++++++++++++++
>  5 files changed, 419 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/i2c/busses/i2c-designware-slave.c
>
...
> +static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
> +{
> +	u32 raw_stat, stat, enabled;
> +	u8 val, slave_activity;
> +
> +	stat = dw_readl(dev, DW_IC_INTR_STAT);
> +	enabled = dw_readl(dev, DW_IC_ENABLE);
> +	raw_stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
> +	slave_activity = ((dw_readl(dev, DW_IC_STATUS) &
> +		DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);
> +
> +	if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY))
> +		return 0;
> +
> +	dev_dbg(dev->dev,
> +		"%#x STAUTS SLAVE_ACTTVITY=%#x : RAW_INTR_STAT=%#x"
> +		" : INTR_STAT=%#x\n",
> +		enabled, slave_activity, raw_stat, stat);
> +

Minor notes:
- Strings that are printed should fit in single line for making easier 
to grep them from sources. Maybe not all of those variables are not 
necessary in this debug print (e.g. are we interested other than bit 0 
in DW_IC_ENABLE and line above already returns if it reads zero).
- Typos "STAUTS SLAVE_ACTTVITY".

You may add my acked by if you want to send another version or I'm fine 
with incremental patch also.

Acked-by: Jarkko Nikula <jarkko.nikula-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
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Re: [PATCH v12 1/2] i2c: designware: add SLAVE mode functions

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1593 bytes --]

On Thu, Jun 22, 2017 at 11:17:32AM +0100, Luis Oliveira wrote:
> - Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
> - Slave functions added to core library file
> - Slave abort sources added to common source file
> - New driver: i2c-designware-slave added
> - Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
>   when supported by the architecture.
> 
> All the SLAVE flow is added but it is not enabled via platform
> driver.
> 
> Signed-off-by: Luis Oliveira <lolivei@synopsys.com>

I fixed this checkpatch warning for you:

WARNING: quoted string split across lines
#391: FILE: drivers/i2c/busses/i2c-designware-slave.c:281:
+		"%#x STAUTS SLAVE_ACTTVITY=%#x : RAW_INTR_STAT=%#x"
+		" : INTR_STAT=%#x\n",

Nice, you fooled two code checkers by having code in comments :) No
need to fix, of course:

    SMATCH
drivers/i2c/busses/i2c-designware-slave.c:318 i2c_dw_irq_handler_slave warn: unused return: stat = i2c_dw_read_clear_intrbits_slave()
drivers/i2c/busses/i2c-designware-slave.c:329 i2c_dw_irq_handler_slave warn: unused return: stat = i2c_dw_read_clear_intrbits_slave()
    CPPCHECK
drivers/i2c/busses/i2c-designware-slave.c:329: style: Variable 'stat' is assigned a value that is never used.

Build warning:

  CC      drivers/i2c/busses/i2c-designware-slave.o
drivers/i2c/busses/i2c-designware-slave.c:173:5: warning: no previous prototype for ‘i2c_dw_reg_slave’ [-Wmissing-prototypes]
 int i2c_dw_reg_slave(struct i2c_client *slave)

I declared the function static to fix it.

Applied to for-next, thanks!


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Re: [PATCH v12 1/2] i2c: designware: add SLAVE mode functions

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1620 bytes --]

On Thu, Jun 22, 2017 at 11:17:32AM +0100, Luis Oliveira wrote:
> - Changes in Kconfig to enable I2C_DESIGNWARE_SLAVE support
> - Slave functions added to core library file
> - Slave abort sources added to common source file
> - New driver: i2c-designware-slave added
> - Changes in the Makefile to compile the I2C_DESIGNWARE_SLAVE module
>   when supported by the architecture.
> 
> All the SLAVE flow is added but it is not enabled via platform
> driver.
> 
> Signed-off-by: Luis Oliveira <lolivei-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>

I fixed this checkpatch warning for you:

WARNING: quoted string split across lines
#391: FILE: drivers/i2c/busses/i2c-designware-slave.c:281:
+		"%#x STAUTS SLAVE_ACTTVITY=%#x : RAW_INTR_STAT=%#x"
+		" : INTR_STAT=%#x\n",

Nice, you fooled two code checkers by having code in comments :) No
need to fix, of course:

    SMATCH
drivers/i2c/busses/i2c-designware-slave.c:318 i2c_dw_irq_handler_slave warn: unused return: stat = i2c_dw_read_clear_intrbits_slave()
drivers/i2c/busses/i2c-designware-slave.c:329 i2c_dw_irq_handler_slave warn: unused return: stat = i2c_dw_read_clear_intrbits_slave()
    CPPCHECK
drivers/i2c/busses/i2c-designware-slave.c:329: style: Variable 'stat' is assigned a value that is never used.

Build warning:

  CC      drivers/i2c/busses/i2c-designware-slave.o
drivers/i2c/busses/i2c-designware-slave.c:173:5: warning: no previous prototype for ‘i2c_dw_reg_slave’ [-Wmissing-prototypes]
 int i2c_dw_reg_slave(struct i2c_client *slave)

I declared the function static to fix it.

Applied to for-next, thanks!


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Re: [PATCH v12 2/2] i2c: designware: enable SLAVE in platform module

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 304 bytes --]

On Thu, Jun 22, 2017 at 11:17:33AM +0100, Luis Oliveira wrote:
> - Slave mode selected in platform module if the support is detected in
>   the DT.
> 
> Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

Applied to for-next, thanks!


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