da9052: Integrate a PMIC I2C access workaround.

This patch was provided by Dialog and it doesn't seem to be yet integrated
with Freescale upstream.

It basically does a write flush on a set of registers.

Dialog contact Christophe.Molle@diasemi.com

Signed-off-by: Alex Gonzalez <alex.gonzalez@digi.com>
(cherry picked from commit 8d5aa68cad489a1bba040dd32c92b0dd565cc881)

1 files changed, 177 insertions, 159 deletions

diff --git a/drivers/mfd/da9052-i2c.c b/drivers/mfd/da9052-i2c.c
index 3a1011682224..1a9fd368db66 100644
--- a/drivers/mfd/da9052-i2c.c
+++ b/drivers/mfd/da9052-i2c.c
@@ -19,6 +19,8 @@ static struct da9052 *da9052_i2c;
 
 #define I2C_CONNECTED 0
 
+#define I2C_BUG_WORKAROUND
+
 static int da9052_i2c_is_connected(void)
 {
 	struct da9052_ssc_msg msg;
@@ -76,6 +78,15 @@ static int __devinit da9052_i2c_probe(struct i2c_client *client,
 
 	 /* Validate I2C connectivity */
         if ( I2C_CONNECTED  == da9052_i2c_is_connected()) {
+		/* Enable Repeated Write Mode permanently */
+		struct da9052_ssc_msg ctrl_msg =
+			{DA9052_CONTROLB_REG, DA9052_CONTROLB_WRITEMODE};
+		if (da9052_i2c_write(da9052_i2c, &ctrl_msg) < 0) {
+			dev_info(&da9052_i2c->i2c_client->dev,
+				 "%s: repeated mode not set!!\n", __func__);
+			return -ENODEV;
+		}
+
                 /* I2C is connected */
                 da9052_i2c->connecting_device = I2C;
                 if( 0!= da9052_ssc_init(da9052_i2c) )
@@ -100,30 +111,77 @@ static int da9052_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+#ifdef I2C_BUG_WORKAROUND
+#define I2C_DUMMY_REG	0xFF
+const unsigned char i2c_flush_data[] = {I2C_DUMMY_REG, 0xFF};
+
+#if 1	/* Enable safe register addresses checking */
+/* DLG TODO: Add read only registers here (they are not affected with write) */
+static inline int da9052_is_i2c_reg_safe(unsigned char reg)
+{
+	const char safe_table[256] = {
+		[DA9052_STATUSA_REG] = 1,
+		[DA9052_STATUSB_REG] = 1,
+		[DA9052_STATUSC_REG] = 1,
+		[DA9052_STATUSD_REG] = 1,
+		[DA9052_EVENTA_REG] = 1,
+		[DA9052_EVENTB_REG] = 1,
+		[DA9052_EVENTC_REG] = 1,
+		[DA9052_EVENTD_REG] = 1,
+		[DA9052_ADCRESL_REG] = 1,
+		[DA9052_ADCRESH_REG] = 1,
+		[DA9052_VDDRES_REG] = 1,
+		[DA9052_ICHGAV_REG] = 1,
+		[DA9052_TBATRES_REG] = 1,
+		[DA9052_ADCIN4RES_REG] = 1,
+		[DA9052_ADCIN5RES_REG] = 1,
+		[DA9052_ADCIN6RES_REG] = 1,
+		[DA9052_TJUNCRES_REG] = 1,
+		[DA9052_TSIXMSB_REG] = 1,
+		[DA9052_TSIYMSB_REG] = 1,
+		[DA9052_TSILSB_REG] = 1,
+		[DA9052_TSIZMSB_REG] = 1,
+		[I2C_DUMMY_REG] = 1,	/* Dummy reg must be a save reg */
+	};
+
+	return safe_table[reg];
+}
+#else
+static inline int da9052_is_i2c_reg_safe(unsigned char reg)
+{
+	return 0;
+}
+#endif
+#endif
+
 int da9052_i2c_write(struct da9052 *da9052, struct da9052_ssc_msg *msg)
 {
 	struct i2c_msg i2cmsg;
-	unsigned char buf[2] = {0};
+	unsigned char buf[4];
 	int ret = 0;
 
-	/* Copy the ssc msg to local character buffer */
-	buf[0] = msg->addr;
-	buf[1] = msg->data;
-
 	/*Construct a i2c msg for a da9052 driver ssc message request */
 	i2cmsg.addr  = da9052->slave_addr;
-	i2cmsg.len   = 2;
 	i2cmsg.buf   = buf;
-
-	/* To write the data on I2C set flag to zero */
 	i2cmsg.flags = 0;
+	i2cmsg.len   = 2;
 
-	/* Start the i2c transfer by calling host i2c driver function */
-	ret = i2c_transfer(da9052->adapter, &i2cmsg, 1);
+	/* Copy the ssc msg and additional data to flush chip I2C registers */
+	buf[0] = msg->addr;
+	buf[1] = msg->data;
 
-	if (ret < 0) {
-		dev_info(&da9052->i2c_client->dev,\
-		"_%s:master_xfer Failed!!\n", __func__);
+#ifdef I2C_BUG_WORKAROUND
+	/* Test, whether register to be accessed needs to be flushed */
+	if (!da9052_is_i2c_reg_safe(msg->addr)) {
+		i2cmsg.len   = 4;
+		buf[2] = i2c_flush_data[0];
+		buf[3] = i2c_flush_data[1];
+	}
+#endif
+	/* Start the i2c transfer by calling host i2c driver function */
+	ret = i2c_transfer(da9052->adapter, &i2cmsg, 1);	if (ret < 0) {
+		dev_info(&da9052->i2c_client->dev,
+			 "%s: i2c_transfer failed!!!\n", __func__);
 		return ret;
 	}
 
@@ -132,10 +190,8 @@ int da9052_i2c_write(struct da9052 *da9052, struct da9052_ssc_msg *msg)
 
 int da9052_i2c_read(struct da9052 *da9052, struct da9052_ssc_msg *msg)
 {
-
-	/*Get the da9052_i2c client details*/
 	unsigned char buf[2] = {0, 0};
-	struct i2c_msg i2cmsg[2];
+	struct i2c_msg i2cmsg[3];
 	int ret = 0;
 
 	/* Copy SSC Msg to local character buffer */
@@ -145,107 +201,86 @@ int da9052_i2c_read(struct da9052 *da9052, struct da9052_ssc_msg *msg)
 	i2cmsg[0].addr  = da9052->slave_addr ;
 	i2cmsg[0].len   = 1;
 	i2cmsg[0].buf   = &buf[0];
-
-	/*To write the data on I2C set flag to zero */
 	i2cmsg[0].flags = 0;
 
-	/* Read the data from da9052*/
 	/*Construct a i2c msg for a da9052 driver ssc message request */
 	i2cmsg[1].addr  = da9052->slave_addr ;
 	i2cmsg[1].len   = 1;
 	i2cmsg[1].buf   = &buf[1];
-
-	/*To read the data on I2C set flag to I2C_M_RD */
 	i2cmsg[1].flags = I2C_M_RD;
 
-	/* Start the i2c transfer by calling host i2c driver function */
+	/* Standard read transfer */
 	ret = i2c_transfer(da9052->adapter, i2cmsg, 2);
-	if (ret < 0) {
-		dev_info(&da9052->i2c_client->dev,\
-		"2 - %s:master_xfer Failed!!\n", __func__);
-		return ret;
+
+#ifdef I2C_BUG_WORKAROUND
+	/* Test, whether register to be accessed needs to be flushed */
+	if (!da9052_is_i2c_reg_safe(msg->addr)) {
+		i2cmsg[2].addr = da9052->slave_addr;
+		i2cmsg[2].len = 2;
+		i2cmsg[2].flags = 0;		/* Write operation */
+		/* i2c_flush_data is only to read from */
+		i2cmsg[2].buf = (unsigned char *)i2c_flush_data;
+
+		/* Read transfer with additional flush write */
+		ret = i2c_transfer(da9052->adapter, &i2cmsg[2], 1);
 	}
+#endif
 
-	msg->data = *i2cmsg[1].buf;
+	if (ret < 0) {
+		dev_info(&da9052->i2c_client->dev,
+			 "%s: i2c_transfer failed!!!\n", __func__);
+	return ret;
+	}
 
+	msg->data = buf[1];
 	return 0;
 }
 
 int da9052_i2c_write_many(struct da9052 *da9052,
 	struct da9052_ssc_msg *sscmsg, int msg_no)
 {
-
 	struct i2c_msg i2cmsg;
-	unsigned char data_buf[MAX_READ_WRITE_CNT+1];
-	struct da9052_ssc_msg ctrlb_msg;
-	struct da9052_ssc_msg *msg_queue = sscmsg;
 	int ret = 0;
-	/* Flag to check if requested registers are contiguous */
-	unsigned char cont_data = 1;
-	unsigned char cnt = 0;
-
-	/* Check if requested registers are contiguous */
-	for (cnt = 1; cnt < msg_no; cnt++) {
-		if ((msg_queue[cnt].addr - msg_queue[cnt-1].addr) != 1) {
-			/* Difference is not 1, i.e. non-contiguous registers */
-			cont_data = 0;
-			break;
-		}
-	}
-
-	if (cont_data == 0) {
-		/* Requested registers are non-contiguous */
-		for (cnt = 0; cnt < msg_no; cnt++) {
-			ret = da9052->write(da9052, &msg_queue[cnt]);
-			if (ret != 0)
-				return ret;
-		}
-		return 0;
-	}
-	/*
-	*  Requested registers are contiguous
-	* or PAGE WRITE sequence of I2C transactions is as below
-	* (slave_addr + reg_addr + data_1 + data_2 + ...)
-	* First read current WRITE MODE via CONTROL_B register of DA9052
-	*/
-	ctrlb_msg.addr = DA9052_CONTROLB_REG;
-	ctrlb_msg.data = 0x0;
-	ret = da9052->read(da9052, &ctrlb_msg);
-
-	if (ret != 0)
-		return ret;
-
-	/* Check if PAGE WRITE mode is set */
-	if (ctrlb_msg.data & DA9052_CONTROLB_WRITEMODE) {
-		/* REPEAT WRITE mode is configured */
-		/* Now set DA9052 into PAGE WRITE mode */
-		ctrlb_msg.data &= ~DA9052_CONTROLB_WRITEMODE;
-		ret = da9052->write(da9052, &ctrlb_msg);
-
-		if (ret != 0)
-			return ret;
-	}
-
-	 /* Put first register address */
-	data_buf[0] = msg_queue[0].addr;
-
-	for (cnt = 0; cnt < msg_no; cnt++)
-		data_buf[cnt+1] = msg_queue[cnt].data;
+	int cnt;
+	unsigned char *data_ptr;
+#ifdef I2C_BUG_WORKAROUND
+	unsigned char data_buf[2*MAX_READ_WRITE_CNT + 2];
+#else
+	unsigned char data_buf[2*MAX_READ_WRITE_CNT];
+#endif
+
+	BUG_ON(msg_no < 0);
+	BUG_ON(msg_no >= MAX_READ_WRITE_CNT);
+/*
+	printk(KERN_CRIT "D9053: %s: write %d messages starting from %hhu reg\n",
+	       __func__, msg_no, sscmsg->addr);
+*/
 
-	/* Construct a i2c msg for PAGE WRITE */
+	/* Construct a i2c msg for REPEATED WRITE */
 	i2cmsg.addr  = da9052->slave_addr ;
-	/* First register address + all data*/
-	i2cmsg.len   = (msg_no + 1);
+	i2cmsg.len   = 2*msg_no;
 	i2cmsg.buf   = data_buf;
-
-	/*To write the data on I2C set flag to zero */
 	i2cmsg.flags = 0;
 
+	for (data_ptr = data_buf, cnt = msg_no; cnt; cnt--) {
+		*(data_ptr++) = sscmsg->addr;
+		*(data_ptr++) = sscmsg->data;
+		sscmsg++;
+	}
+#ifdef I2C_BUG_WORKAROUND
+	/* Test, whether last register to be accessed needs to be flushed */
+	if (msg_no != 0 && !da9052_is_i2c_reg_safe(sscmsg[-1].addr)) {
+		i2cmsg.len += 2;
+		*(data_ptr++) = i2c_flush_data[0];
+		*data_ptr = i2c_flush_data[1];
+	}
+#endif
+
 	/* Start the i2c transfer by calling host i2c driver function */
 	ret = i2c_transfer(da9052->adapter, &i2cmsg, 1);
 	if (ret < 0) {
-		dev_info(&da9052->i2c_client->dev,\
-		"1 - i2c_transfer function falied in [%s]!!!\n", __func__);
+		dev_info(&da9052->i2c_client->dev,
+			 "%s: i2c_transfer failed!!!\n", __func__);
 		return ret;
 	}
 
@@ -255,83 +290,66 @@ int da9052_i2c_write_many(struct da9052 *da9052,
 int da9052_i2c_read_many(struct da9052 *da9052,
 	struct da9052_ssc_msg *sscmsg, int msg_no)
 {
-
-	struct i2c_msg i2cmsg;
+	struct i2c_msg i2cmsg[2];
 	unsigned char data_buf[MAX_READ_WRITE_CNT];
-	struct da9052_ssc_msg *msg_queue = sscmsg;
 	int ret = 0;
-	/* Flag to check if requested registers are contiguous */
-	unsigned char cont_data = 1;
-	unsigned char cnt = 0;
-
-	/* Check if requested registers are contiguous */
-	for (cnt = 1; cnt < msg_no; cnt++) {
-		if ((msg_queue[cnt].addr - msg_queue[cnt-1].addr) != 1) {
-			/* Difference is not 1, i.e. non-contiguous registers */
-			cont_data = 0;
-			break;
-		}
-	}
-
-	if (cont_data == 0) {
-		/* Requested registers are non-contiguous */
-		for (cnt = 0; cnt < msg_no; cnt++) {
-			ret = da9052->read(da9052, &msg_queue[cnt]);
-			if (ret != 0) {
-				dev_info(&da9052->i2c_client->dev,\
-				"Error in %s", __func__);
-				return ret;
-			}
-		}
-		return 0;
-	}
-
-	/*
-	* We want to perform PAGE READ via I2C
-	* For PAGE READ sequence of I2C transactions is as below
-	* (slave_addr + reg_addr) + (slave_addr + data_1 + data_2 + ...)
-	*/
-	/* Copy address of first register */
-	data_buf[0] = msg_queue[0].addr;
-
-	/* Construct a i2c msg for first transaction of PAGE READ i.e. write */
-	i2cmsg.addr  = da9052->slave_addr ;
-	i2cmsg.len   = 1;
-	i2cmsg.buf   = data_buf;
+	int expected_addr = 0xFF;
+	int cnt;
 
-	/*To write the data on I2C set flag to zero */
-	i2cmsg.flags = 0;
-
-	/* Start the i2c transfer by calling host i2c driver function */
-	ret = i2c_transfer(da9052->adapter, &i2cmsg, 1);
-	if (ret < 0) {
-		dev_info(&da9052->i2c_client->dev,\
-		"1 - i2c_transfer function falied in [%s]!!!\n", __func__);
-		return ret;
-	}
-
-	/* Now Read the data from da9052 */
-	/* Construct a i2c msg for second transaction of PAGE READ i.e. read */
-	i2cmsg.addr  = da9052->slave_addr ;
-	i2cmsg.len   = msg_no;
-	i2cmsg.buf   = data_buf;
+	BUG_ON(msg_no < 0);
+	BUG_ON(msg_no >= MAX_READ_WRITE_CNT);
+/*
+	printk(KERN_CRIT "D9053: %s: read %d messages starting from %hhu reg\n",
+	       __func__, msg_no, sscmsg->addr);
+*/
 
-	/*To read the data on I2C set flag to I2C_M_RD */
-	i2cmsg.flags = I2C_M_RD;
+	/* Construct a i2c msgs for a da9052 driver ssc message request */
+	cnt = 0;
+	do {
+		/* Build messages for read transaction */
+		i2cmsg[0].addr  = da9052->slave_addr;
+		i2cmsg[0].buf   = &sscmsg[cnt].addr;
+		i2cmsg[0].flags = 0;
+		i2cmsg[0].len   = 1;
+		i2cmsg[1].addr  = da9052->slave_addr;
+		i2cmsg[1].buf   = &data_buf[cnt];
+		i2cmsg[1].flags = I2C_M_RD;
+		/* Grab consecutive register reads into one message */
+		for (i2cmsg[1].len = 0, expected_addr = sscmsg[cnt].addr;
+			(cnt < msg_no) && (sscmsg[cnt].addr == expected_addr);
+			cnt++, expected_addr++)
+		{
+			i2cmsg[1].len++;
+		}
 
-	/* Start the i2c transfer by calling host i2c driver function */
-	ret = i2c_transfer(da9052->adapter,
-		&i2cmsg, 1);
-	if (ret < 0) {
-		dev_info(&da9052->i2c_client->dev,\
-		"2 - i2c_transfer function falied in [%s]!!!\n", __func__);
-		return ret;
+		/* Perform read transaction */
+		ret = i2c_transfer(da9052->adapter, i2cmsg, 2);
+		if (ret < 0) {
+			dev_info(&da9052->i2c_client->dev,
+				 "%s: i2c_transfer failed!!!\n", __func__);
+			return ret;
+		}
+	} while (cnt < msg_no);
+
+#ifdef I2C_BUG_WORKAROUND
+	/* Test, whether last register to be accessed needs to be flushed */
+	if (!da9052_is_i2c_reg_safe(sscmsg[msg_no-1].addr)) {
+		i2cmsg[0].addr  = da9052->slave_addr;
+		i2cmsg[0].len   = 2;
+		i2cmsg[0].flags = 0;	 /* Write operation */
+		/* i2c_flush_data is only to read from */
+		i2cmsg[0].buf   = (unsigned char *)i2c_flush_data;
+
+		ret = i2c_transfer(da9052->adapter, i2cmsg, 1);
+		if (ret < 0) {
+			dev_info(&da9052->i2c_client->dev,
+				 "%s: i2c_transfer failed!!!\n", __func__);
+			return ret;
+		}
 	}
+#endif
 
-	/* Gather READ data */
-	for (cnt = 0; cnt < msg_no; cnt++)
-		sscmsg[cnt].data = data_buf[cnt];
-
+	for (cnt = 0; cnt < msg_no; cnt++) sscmsg[cnt].data = data_buf[cnt];
 	return 0;
 }