net: txgbe: Register I2C platform device

Register the platform device to use Designware I2C bus master driver.
Use regmap to read/write I2C device region from given base offset.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Piotr Raczynski <piotr.raczynski@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/wangxun/Kconfig

@@ -41,6 +41,9 @@ config TXGBE
 	tristate "Wangxun(R) 10GbE PCI Express adapters support"
 	depends on PCI
 	depends on COMMON_CLK
+	select REGMAP
+	select I2C
+	select I2C_DESIGNWARE_PLATFORM
 	select LIBWX
 	help
 	  This driver supports Wangxun(R) 10GbE PCI Express family of

drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c

@@ -6,6 +6,8 @@
 #include <linux/clkdev.h>
 #include <linux/i2c.h>
 #include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
 
 #include "../libwx/wx_type.h"
 #include "txgbe_type.h"
@@ -98,6 +100,64 @@ static int txgbe_clock_register(struct txgbe *txgbe)
 	return 0;
 }
 
+static int txgbe_i2c_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct wx *wx = context;
+
+	*val = rd32(wx, reg + TXGBE_I2C_BASE);
+
+	return 0;
+}
+
+static int txgbe_i2c_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct wx *wx = context;
+
+	wr32(wx, reg + TXGBE_I2C_BASE, val);
+
+	return 0;
+}
+
+static const struct regmap_config i2c_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_read = txgbe_i2c_read,
+	.reg_write = txgbe_i2c_write,
+	.fast_io = true,
+};
+
+static int txgbe_i2c_register(struct txgbe *txgbe)
+{
+	struct platform_device_info info = {};
+	struct platform_device *i2c_dev;
+	struct regmap *i2c_regmap;
+	struct pci_dev *pdev;
+	struct wx *wx;
+
+	wx = txgbe->wx;
+	pdev = wx->pdev;
+	i2c_regmap = devm_regmap_init(&pdev->dev, NULL, wx, &i2c_regmap_config);
+	if (IS_ERR(i2c_regmap)) {
+		wx_err(wx, "failed to init I2C regmap\n");
+		return PTR_ERR(i2c_regmap);
+	}
+
+	info.parent = &pdev->dev;
+	info.fwnode = software_node_fwnode(txgbe->nodes.group[SWNODE_I2C]);
+	info.name = "i2c_designware";
+	info.id = (pdev->bus->number << 8) | pdev->devfn;
+
+	info.res = &DEFINE_RES_IRQ(pdev->irq);
+	info.num_res = 1;
+	i2c_dev = platform_device_register_full(&info);
+	if (IS_ERR(i2c_dev))
+		return PTR_ERR(i2c_dev);
+
+	txgbe->i2c_dev = i2c_dev;
+
+	return 0;
+}
+
 int txgbe_init_phy(struct txgbe *txgbe)
 {
 	int ret;
@@ -114,8 +174,17 @@ int txgbe_init_phy(struct txgbe *txgbe)
 		goto err_unregister_swnode;
 	}
 
+	ret = txgbe_i2c_register(txgbe);
+	if (ret) {
+		wx_err(txgbe->wx, "failed to init i2c interface: %d\n", ret);
+		goto err_unregister_clk;
+	}
+
 	return 0;
 
+err_unregister_clk:
+	clkdev_drop(txgbe->clock);
+	clk_unregister(txgbe->clk);
 err_unregister_swnode:
 	software_node_unregister_node_group(txgbe->nodes.group);
 
@@ -124,6 +193,7 @@ int txgbe_init_phy(struct txgbe *txgbe)
 
 void txgbe_remove_phy(struct txgbe *txgbe)
 {
+	platform_device_unregister(txgbe->i2c_dev);
 	clkdev_drop(txgbe->clock);
 	clk_unregister(txgbe->clk);
 	software_node_unregister_node_group(txgbe->nodes.group);

drivers/net/ethernet/wangxun/txgbe/txgbe_type.h

@@ -55,6 +55,9 @@
 #define TXGBE_TS_CTL                            0x10300
 #define TXGBE_TS_CTL_EVAL_MD                    BIT(31)
 
+/* I2C registers */
+#define TXGBE_I2C_BASE                          0x14900
+
 /* Part Number String Length */
 #define TXGBE_PBANUM_LENGTH                     32
 
@@ -147,6 +150,7 @@ struct txgbe_nodes {
 struct txgbe {
 	struct wx *wx;
 	struct txgbe_nodes nodes;
+	struct platform_device *i2c_dev;
 	struct clk_lookup *clock;
 	struct clk *clk;
 };