rtc: rx6110: add i2c support

The RX6110 also supports I2C, so this patch adds support for it to the
driver.

This also renames the SPI specific functions and variables to include
`_spi_` in their names.

Signed-off-by: Claudius Heine <ch@denx.de>
Signed-off-by: Henning Schild <henning.schild@siemens.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201117121817.953924-3-ch@denx.de

drivers/rtc/Kconfig

@@ -817,15 +817,6 @@ config RTC_DRV_RX4581
 	  This driver can also be built as a module. If so the module
 	  will be called rtc-rx4581.
 
-config RTC_DRV_RX6110
-	tristate "Epson RX-6110"
-	select REGMAP_SPI
-	help
-	  If you say yes here you will get support for the Epson RX-6110.
-
-	  This driver can also be built as a module. If so the module
-	  will be called rtc-rx6110.
-
 config RTC_DRV_RS5C348
 	tristate "Ricoh RS5C348A/B"
 	help
@@ -936,6 +927,17 @@ config RTC_DRV_RV3029_HWMON
 	  Say Y here if you want to expose temperature sensor data on
 	  rtc-rv3029.
 
+config RTC_DRV_RX6110
+	tristate "Epson RX-6110"
+	depends on RTC_I2C_AND_SPI
+	select REGMAP_SPI if SPI_MASTER
+	select REGMAP_I2C if I2C
+	help
+	  If you say yes here you will get support for the Epson RX-6110.
+
+	  This driver can also be built as a module. If so the module
+	  will be called rtc-rx6110.
+
 comment "Platform RTC drivers"
 
 # this 'CMOS' RTC driver is arch dependent because it requires

drivers/rtc/rtc-rx6110.c

@@ -16,6 +16,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/spi/spi.h>
+#include <linux/i2c.h>
 
 /* RX-6110 Register definitions */
 #define RX6110_REG_SEC		0x10
@@ -310,6 +311,27 @@ static const struct rtc_class_ops rx6110_rtc_ops = {
 	.set_time = rx6110_set_time,
 };
 
+static int rx6110_probe(struct rx6110_data *rx6110, struct device *dev)
+{
+	int err;
+
+	rx6110->rtc = devm_rtc_device_register(dev,
+					       RX6110_DRIVER_NAME,
+					       &rx6110_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(rx6110->rtc))
+		return PTR_ERR(rx6110->rtc);
+
+	err = rx6110_init(rx6110);
+	if (err)
+		return err;
+
+	rx6110->rtc->max_user_freq = 1;
+
+	return 0;
+}
+
+#ifdef CONFIG_SPI_MASTER
 static struct regmap_config regmap_spi_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
@@ -318,13 +340,12 @@ static struct regmap_config regmap_spi_config = {
 };
 
 /**
- * rx6110_probe - initialize rtc driver
+ * rx6110_spi_probe - initialize rtc driver
  * @spi: pointer to spi device
  */
-static int rx6110_probe(struct spi_device *spi)
+static int rx6110_spi_probe(struct spi_device *spi)
 {
 	struct rx6110_data *rx6110;
-	int err;
 
 	if ((spi->bits_per_word && spi->bits_per_word != 8) ||
 	    (spi->max_speed_hz > 2000000) ||
@@ -346,44 +367,142 @@ static int rx6110_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, rx6110);
 
-	rx6110->rtc = devm_rtc_device_register(&spi->dev,
-					       RX6110_DRIVER_NAME,
-					       &rx6110_rtc_ops, THIS_MODULE);
-
-	if (IS_ERR(rx6110->rtc))
-		return PTR_ERR(rx6110->rtc);
-
-	err = rx6110_init(rx6110);
-	if (err)
-		return err;
-
-	rx6110->rtc->max_user_freq = 1;
-
-	return 0;
+	return rx6110_probe(rx6110, &spi->dev);
 }
 
-static const struct spi_device_id rx6110_id[] = {
+static const struct spi_device_id rx6110_spi_id[] = {
 	{ "rx6110", 0 },
 	{ }
 };
-MODULE_DEVICE_TABLE(spi, rx6110_id);
+MODULE_DEVICE_TABLE(spi, rx6110_spi_id);
 
 static const struct of_device_id rx6110_spi_of_match[] = {
 	{ .compatible = "epson,rx6110" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
 
-static struct spi_driver rx6110_driver = {
+static struct spi_driver rx6110_spi_driver = {
 	.driver = {
 		.name = RX6110_DRIVER_NAME,
 		.of_match_table = of_match_ptr(rx6110_spi_of_match),
 	},
-	.probe		= rx6110_probe,
-	.id_table	= rx6110_id,
+	.probe		= rx6110_spi_probe,
+	.id_table	= rx6110_spi_id,
+};
+
+static int rx6110_spi_register(void)
+{
+	return spi_register_driver(&rx6110_spi_driver);
+}
+
+static void rx6110_spi_unregister(void)
+{
+	spi_unregister_driver(&rx6110_spi_driver);
+}
+#else
+static int rx6110_spi_register(void)
+{
+	return 0;
+}
+
+static void rx6110_spi_unregister(void)
+{
+}
+#endif /* CONFIG_SPI_MASTER */
+
+#ifdef CONFIG_I2C
+static struct regmap_config regmap_i2c_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = RX6110_REG_IRQ,
+	.read_flag_mask = 0x80,
 };
 
-module_spi_driver(rx6110_driver);
+static int rx6110_i2c_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct rx6110_data *rx6110;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
+				| I2C_FUNC_SMBUS_I2C_BLOCK)) {
+		dev_err(&adapter->dev,
+			"doesn't support required functionality\n");
+		return -EIO;
+	}
+
+	rx6110 = devm_kzalloc(&client->dev, sizeof(*rx6110), GFP_KERNEL);
+	if (!rx6110)
+		return -ENOMEM;
+
+	rx6110->regmap = devm_regmap_init_i2c(client, &regmap_i2c_config);
+	if (IS_ERR(rx6110->regmap)) {
+		dev_err(&client->dev, "regmap init failed for rtc rx6110\n");
+		return PTR_ERR(rx6110->regmap);
+	}
+
+	i2c_set_clientdata(client, rx6110);
+
+	return rx6110_probe(rx6110, &client->dev);
+}
+
+static const struct i2c_device_id rx6110_i2c_id[] = {
+	{ "rx6110", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, rx6110_i2c_id);
+
+static struct i2c_driver rx6110_i2c_driver = {
+	.driver = {
+		.name = RX6110_DRIVER_NAME,
+	},
+	.probe		= rx6110_i2c_probe,
+	.id_table	= rx6110_i2c_id,
+};
+
+static int rx6110_i2c_register(void)
+{
+	return i2c_add_driver(&rx6110_i2c_driver);
+}
+
+static void rx6110_i2c_unregister(void)
+{
+	i2c_del_driver(&rx6110_i2c_driver);
+}
+#else
+static int rx6110_i2c_register(void)
+{
+	return 0;
+}
+
+static void rx6110_i2c_unregister(void)
+{
+}
+#endif /* CONFIG_I2C */
+
+static int __init rx6110_module_init(void)
+{
+	int ret;
+
+	ret = rx6110_spi_register();
+	if (ret)
+		return ret;
+
+	ret = rx6110_i2c_register();
+	if (ret)
+		rx6110_spi_unregister();
+
+	return ret;
+}
+module_init(rx6110_module_init);
+
+static void __exit rx6110_module_exit(void)
+{
+	rx6110_spi_unregister();
+	rx6110_i2c_unregister();
+}
+module_exit(rx6110_module_exit);
 
 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
 MODULE_DESCRIPTION("RX-6110 SA RTC driver");