Revert "serial: max310x: implement I2C support"

This reverts commit 85d79478710ad2cbf11857aec107084a7104943e which is
commit 2e1f2d9a9bdbe12ee475c82a45ac46a278e8049a upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I16bdb88a23acb5148cb53af95b47e75c14ce83c3
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

2 files changed, 1 insertions, 135 deletions

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 141195dce98b..940db397dae2 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -342,7 +342,6 @@ config SERIAL_MAX310X
 	depends on SPI_MASTER
 	select SERIAL_CORE
 	select REGMAP_SPI if SPI_MASTER
-	select REGMAP_I2C if I2C
 	help
 	  This selects support for an advanced UART from Maxim (Dallas).
 	  Supported ICs are MAX3107, MAX3108, MAX3109, MAX14830.
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index ed1aaa19854f..b90281ac54c8 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -14,7 +14,6 @@
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/gpio/driver.h>
-#include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/property.h>
@@ -74,7 +73,6 @@
 
 /* Extended registers */
 #define MAX310X_SPI_REVID_EXTREG	MAX310X_REG_05 /* Revision ID */
-#define MAX310X_I2C_REVID_EXTREG	(0x25) /* Revision ID */
 
 /* IRQ register bits */
 #define MAX310X_IRQ_LSR_BIT		(1 << 0) /* LSR interrupt */
@@ -262,10 +260,6 @@ struct max310x_if_cfg {
 };
 
 struct max310x_devtype {
-	struct {
-		unsigned short min;
-		unsigned short max;
-	} slave_addr;
 	char	name[9];
 	int	nr;
 	u8	mode1;
@@ -437,10 +431,6 @@ static const struct max310x_devtype max3107_devtype = {
 	.mode1	= MAX310X_MODE1_AUTOSLEEP_BIT | MAX310X_MODE1_IRQSEL_BIT,
 	.detect	= max3107_detect,
 	.power	= max310x_power,
-	.slave_addr	= {
-		.min = 0x2c,
-		.max = 0x2f,
-	},
 };
 
 static const struct max310x_devtype max3108_devtype = {
@@ -449,10 +439,6 @@ static const struct max310x_devtype max3108_devtype = {
 	.mode1	= MAX310X_MODE1_AUTOSLEEP_BIT,
 	.detect	= max3108_detect,
 	.power	= max310x_power,
-	.slave_addr	= {
-		.min = 0x60,
-		.max = 0x6f,
-	},
 };
 
 static const struct max310x_devtype max3109_devtype = {
@@ -461,10 +447,6 @@ static const struct max310x_devtype max3109_devtype = {
 	.mode1	= MAX310X_MODE1_AUTOSLEEP_BIT,
 	.detect	= max3109_detect,
 	.power	= max310x_power,
-	.slave_addr	= {
-		.min = 0x60,
-		.max = 0x6f,
-	},
 };
 
 static const struct max310x_devtype max14830_devtype = {
@@ -473,10 +455,6 @@ static const struct max310x_devtype max14830_devtype = {
 	.mode1	= MAX310X_MODE1_IRQSEL_BIT,
 	.detect	= max14830_detect,
 	.power	= max14830_power,
-	.slave_addr	= {
-		.min = 0x60,
-		.max = 0x6f,
-	},
 };
 
 static bool max310x_reg_writeable(struct device *dev, unsigned int reg)
@@ -1579,97 +1557,6 @@ static struct spi_driver max310x_spi_driver = {
 };
 #endif
 
-#ifdef CONFIG_I2C
-static int max310x_i2c_extended_reg_enable(struct device *dev, bool enable)
-{
-	return 0;
-}
-
-static struct regmap_config regcfg_i2c = {
-	.reg_bits = 8,
-	.val_bits = 8,
-	.cache_type = REGCACHE_RBTREE,
-	.writeable_reg = max310x_reg_writeable,
-	.volatile_reg = max310x_reg_volatile,
-	.precious_reg = max310x_reg_precious,
-	.max_register = MAX310X_I2C_REVID_EXTREG,
-};
-
-static const struct max310x_if_cfg max310x_i2c_if_cfg = {
-	.extended_reg_enable = max310x_i2c_extended_reg_enable,
-	.rev_id_reg = MAX310X_I2C_REVID_EXTREG,
-};
-
-static unsigned short max310x_i2c_slave_addr(unsigned short addr,
-					     unsigned int nr)
-{
-	/*
-	 * For MAX14830 and MAX3109, the slave address depends on what the
-	 * A0 and A1 pins are tied to.
-	 * See Table I2C Address Map of the datasheet.
-	 * Based on that table, the following formulas were determined.
-	 * UART1 - UART0 = 0x10
-	 * UART2 - UART1 = 0x20 + 0x10
-	 * UART3 - UART2 = 0x10
-	 */
-
-	addr -= nr * 0x10;
-
-	if (nr >= 2)
-		addr -= 0x20;
-
-	return addr;
-}
-
-static int max310x_i2c_probe(struct i2c_client *client)
-{
-	const struct max310x_devtype *devtype =
-			device_get_match_data(&client->dev);
-	struct i2c_client *port_client;
-	struct regmap *regmaps[4];
-	unsigned int i;
-	u8 port_addr;
-
-	if (client->addr < devtype->slave_addr.min ||
-		client->addr > devtype->slave_addr.max)
-		return dev_err_probe(&client->dev, -EINVAL,
-				     "Slave addr 0x%x outside of range [0x%x, 0x%x]\n",
-				     client->addr, devtype->slave_addr.min,
-				     devtype->slave_addr.max);
-
-	regmaps[0] = devm_regmap_init_i2c(client, &regcfg_i2c);
-
-	for (i = 1; i < devtype->nr; i++) {
-		port_addr = max310x_i2c_slave_addr(client->addr, i);
-		port_client = devm_i2c_new_dummy_device(&client->dev,
-							client->adapter,
-							port_addr);
-
-		regmaps[i] = devm_regmap_init_i2c(port_client, &regcfg_i2c);
-	}
-
-	return max310x_probe(&client->dev, devtype, &max310x_i2c_if_cfg,
-			     regmaps, client->irq);
-}
-
-static int max310x_i2c_remove(struct i2c_client *client)
-{
-	max310x_remove(&client->dev);
-
-	return 0;
-}
-
-static struct i2c_driver max310x_i2c_driver = {
-	.driver = {
-		.name		= MAX310X_NAME,
-		.of_match_table	= max310x_dt_ids,
-		.pm		= &max310x_pm_ops,
-	},
-	.probe_new	= max310x_i2c_probe,
-	.remove		= max310x_i2c_remove,
-};
-#endif
-
 static int __init max310x_uart_init(void)
 {
 	int ret;
@@ -1683,35 +1570,15 @@ static int __init max310x_uart_init(void)
 #ifdef CONFIG_SPI_MASTER
 	ret = spi_register_driver(&max310x_spi_driver);
 	if (ret)
-		goto err_spi_register;
-#endif
-
-#ifdef CONFIG_I2C
-	ret = i2c_add_driver(&max310x_i2c_driver);
-	if (ret)
-		goto err_i2c_register;
+		uart_unregister_driver(&max310x_uart);
 #endif
 
-	return 0;
-
-#ifdef CONFIG_I2C
-err_i2c_register:
-	spi_unregister_driver(&max310x_spi_driver);
-#endif
-
-err_spi_register:
-	uart_unregister_driver(&max310x_uart);
-
 	return ret;
 }
 module_init(max310x_uart_init);
 
 static void __exit max310x_uart_exit(void)
 {
-#ifdef CONFIG_I2C
-	i2c_del_driver(&max310x_i2c_driver);
-#endif
-
 #ifdef CONFIG_SPI_MASTER
 	spi_unregister_driver(&max310x_spi_driver);
 #endif