RE: Upstream of minor i2c enhancement of i2c kernel driver code

[Ng, Angela]

Adding   linux-kernel@xxxxxxxxxxxxxxx and wsa@xxxxxxxxxxxxx  for the recipients of the patches. 

Thanks & Best Regards,
Ng Sock Chan (Angela)
吴姝臻
Software Engineer (HPN) 


-----Original Message-----
From: Ng, Angela 
Sent: Monday, March 19, 2018 1:32 PM
To: 'linux-i2c@xxxxxxxxxxxxxxx' <linux-i2c@xxxxxxxxxxxxxxx>
Subject: RE: Upstream of minor i2c enhancement of i2c kernel driver code



Hello Linux-i2c community, 

We would like to upstream a minor enhancement for i2c-i801.c.
This patch adds  I2C_FUNC_SMBUS_PROC_CALL functionality to i2c-i801.c. 


diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c ===================================================================
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -783,6 +783,14 @@
 			outb_p(command, SMBHSTCMD(priv));
 		block = 1;
 		break;
+	case I2C_SMBUS_PROC_CALL:
+		outb_p(((addr & 0x7f) << 1)| (I2C_SMBUS_WRITE & 0x01),
+			SMBHSTADD(priv));
+		outb_p(command, SMBHSTCMD(priv));
+		outb_p(data->word & 0xff, SMBHSTDAT0(priv));
+		outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1(priv));
+		xact = I801_PROC_CALL;
+		break;
 	default:
 		dev_err(&priv->pci_dev->dev, "Unsupported transaction %d\n",
 			size);
@@ -799,9 +807,21 @@
 	if (block)
 		ret = i801_block_transaction(priv, data, read_write, size,
 					     hwpec);
-	else
+	else {
+		unsigned char hostc = 0;
+
+		if (xact == I801_PROC_CALL) {
+			/* clear I2C_EN bit in configuration register for proc calls */
+			pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &hostc);
+			pci_write_config_byte(priv->pci_dev, SMBHSTCFG,
+				(hostc & (~SMBHSTCFG_I2C_EN)));
+		}
 		ret = i801_transaction(priv, xact);
-
+		if (xact == I801_PROC_CALL) {
+			/* restore saved configuration register value */
+			pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hostc);
+		}
+	}
 	/* Some BIOSes don't like it when PEC is enabled at reboot or resume
 	   time, so we forcibly disable it after every transaction. Turn off
 	   E32B for the same reason. */
@@ -813,7 +833,14 @@
 		goto out;
 	if (ret)
 		goto out;
-	if ((read_write == I2C_SMBUS_WRITE) || (xact == I801_QUICK))
+
+	/* i2c-dev.h has defined i2c_smbus_proc_call to pass I2C_SMBUS_WRITE
+	   to the nderlying driver. However, process call is only defined for
+	   read transactions. Process call writes will be using
+	   i2c_smbus_write_i2c_block_data driver api.
+	*/
+	if (((read_write == I2C_SMBUS_WRITE) || (xact == I801_QUICK)) &&
+		(xact != I801_PROC_CALL))
 		goto out;
 
 	switch (xact & 0x7f) {
@@ -821,6 +848,7 @@
 	case I801_BYTE_DATA:
 		data->byte = inb_p(SMBHSTDAT0(priv));
 		break;
+	case I801_PROC_CALL:
 	case I801_WORD_DATA:
 		data->word = inb_p(SMBHSTDAT0(priv)) +
 			     (inb_p(SMBHSTDAT1(priv)) << 8); @@ -840,6 +868,7 @@
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 	       I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK |
+	       I2C_FUNC_SMBUS_PROC_CALL |
 	       ((priv->features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0) |
 	       ((priv->features & FEATURE_I2C_BLOCK_READ) ?
 		I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0);

 


Thanks & Best Regards,
Ng Sock Chan (Angela)
吴姝臻
Software Engineer (HPN)