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[v3,1/5] i2c: piix4: Allow more than two algo selection for SMBus

Message ID 20240906071201.2254354-2-Shyam-sundar.S-k@amd.com
State New
Headers show
Series Introduce AMD ASF Controller Support to the i2c-piix4 driver | expand

Commit Message

Shyam Sundar S K Sept. 6, 2024, 7:11 a.m. UTC 
The current implementation of the piix4 driver has a limitation in that it
only supports two algorithms for the I2C adapter:

- SB800 Algorithm: This is used for newer AMD chipsets.
- Legacy PIIX4 Algorithm: This is used for older systems.

The selection between these two algorithms is controlled by a boolean
parameter in the piix4_add_adapter() function. This means that the driver
can only toggle between these two options, which limits its flexibility.

AMD's SMBus (System Management Bus) implementation supports additional
functionalities, such as ASF (Alert Standard Format). ASF is a protocol
used for system management and monitoring, which can be part of the SoC
(System on Chip). To support ASF or any other future algorithms, the
driver needs to be more flexible in its algorithm selection.

The proposed change involves modifying the piix4_add_adapter() function to
accommodate more than just two algorithm selections. Instead of using a
boolean parameter to select between two algorithms, the function signature
will be updated to allow for multiple algorithm options.

Co-developed-by: Sanket Goswami <Sanket.Goswami@amd.com>
Signed-off-by: Sanket Goswami <Sanket.Goswami@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
---
 drivers/i2c/busses/i2c-piix4.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)
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Patch

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 4e32d57ae0bf..d56083e58a2d 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -165,6 +165,11 @@  struct sb800_mmio_cfg {
 	bool use_mmio;
 };
 
+enum piix4_algo {
+	PIIX4_SB800,
+	PIIX4_SMBUS,
+};
+
 struct i2c_piix4_adapdata {
 	unsigned short smba;
 
@@ -173,6 +178,7 @@  struct i2c_piix4_adapdata {
 	bool notify_imc;
 	u8 port;		/* Port number, shifted */
 	struct sb800_mmio_cfg mmio_cfg;
+	u8 algo_select;
 };
 
 static int piix4_sb800_region_request(struct device *dev,
@@ -929,7 +935,7 @@  static struct i2c_adapter *piix4_aux_adapter;
 static int piix4_adapter_count;
 
 static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
-			     bool sb800_main, u8 port, bool notify_imc,
+			     enum piix4_algo algo, u8 port, bool notify_imc,
 			     u8 hw_port_nr, const char *name,
 			     struct i2c_adapter **padap)
 {
@@ -945,8 +951,18 @@  static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 
 	adap->owner = THIS_MODULE;
 	adap->class = I2C_CLASS_HWMON;
-	adap->algo = sb800_main ? &piix4_smbus_algorithm_sb800
-				: &smbus_algorithm;
+
+	switch (algo) {
+	case PIIX4_SMBUS:
+		adap->algo = &smbus_algorithm;
+		break;
+	case PIIX4_SB800:
+		adap->algo = &piix4_smbus_algorithm_sb800;
+		break;
+	default:
+		dev_err(&dev->dev, "Unsupported SMBus algorithm\n");
+		return -EINVAL;
+	}
 
 	adapdata = kzalloc(sizeof(*adapdata), GFP_KERNEL);
 	if (adapdata == NULL) {
@@ -957,7 +973,7 @@  static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 
 	adapdata->mmio_cfg.use_mmio = piix4_sb800_use_mmio(dev);
 	adapdata->smba = smba;
-	adapdata->sb800_main = sb800_main;
+	adapdata->algo_select = algo;
 	adapdata->port = port << piix4_port_shift_sb800;
 	adapdata->notify_imc = notify_imc;
 
@@ -1013,7 +1029,7 @@  static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba,
 	for (port = 0; port < piix4_adapter_count; port++) {
 		u8 hw_port_nr = port == 0 ? 0 : port + 1;
 
-		retval = piix4_add_adapter(dev, smba, true, port, notify_imc,
+		retval = piix4_add_adapter(dev, smba, PIIX4_SB800, port, notify_imc,
 					   hw_port_nr,
 					   piix4_main_port_names_sb800[port],
 					   &piix4_main_adapters[port]);
@@ -1085,7 +1101,7 @@  static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 			return retval;
 
 		/* Try to register main SMBus adapter, give up if we can't */
-		retval = piix4_add_adapter(dev, retval, false, 0, false, 0,
+		retval = piix4_add_adapter(dev, retval, PIIX4_SMBUS, 0, false, 0,
 					   "", &piix4_main_adapters[0]);
 		if (retval < 0)
 			return retval;
@@ -1114,7 +1130,7 @@  static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if (retval > 0) {
 		/* Try to add the aux adapter if it exists,
 		 * piix4_add_adapter will clean up if this fails */
-		piix4_add_adapter(dev, retval, false, 0, false, 1,
+		piix4_add_adapter(dev, retval, PIIX4_SMBUS, 0, false, 1,
 				  is_sb800 ? piix4_aux_port_name_sb800 : "",
 				  &piix4_aux_adapter);
 	}