platform/x86: mlx-platform: Add support for tachometer speed register

Add support for tachometer speed register for the next generation
systems MQMB7xx, MSN37xx, MSN34xx, MSN38xx.

All these systems support tachometer speed capability register.
This register is to be provided mlxreg-fan driver.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/mlx-platform.c

@@ -72,6 +72,7 @@
 #define MLXPLAT_CPLD_LPC_REG_FAN_CAP1_OFFSET	0xf5
 #define MLXPLAT_CPLD_LPC_REG_FAN_CAP2_OFFSET	0xf6
 #define MLXPLAT_CPLD_LPC_REG_FAN_DRW_CAP_OFFSET	0xf7
+#define MLXPLAT_CPLD_LPC_REG_TACHO_SPEED_OFFSET	0xf8
 #define MLXPLAT_CPLD_LPC_IO_RANGE		0x100
 #define MLXPLAT_CPLD_LPC_I2C_CH1_OFF		0xdb
 #define MLXPLAT_CPLD_LPC_I2C_CH2_OFF		0xda
@@ -1339,6 +1340,10 @@ static struct mlxreg_core_data mlxplat_mlxcpld_default_fan_data[] = {
 		.capability = MLXPLAT_CPLD_LPC_REG_FAN_CAP2_OFFSET,
 		.bit = BIT(3),
 	},
+	{
+		.label = "conf",
+		.capability = MLXPLAT_CPLD_LPC_REG_TACHO_SPEED_OFFSET,
+	},
 };
 
 static struct mlxreg_core_platform_data mlxplat_default_fan_data = {
@@ -1428,6 +1433,7 @@ static bool mlxplat_mlxcpld_readable_reg(struct device *dev, unsigned int reg)
 	case MLXPLAT_CPLD_LPC_REG_FAN_CAP1_OFFSET:
 	case MLXPLAT_CPLD_LPC_REG_FAN_CAP2_OFFSET:
 	case MLXPLAT_CPLD_LPC_REG_FAN_DRW_CAP_OFFSET:
+	case MLXPLAT_CPLD_LPC_REG_TACHO_SPEED_OFFSET:
 		return true;
 	}
 	return false;
@@ -1484,6 +1490,7 @@ static bool mlxplat_mlxcpld_volatile_reg(struct device *dev, unsigned int reg)
 	case MLXPLAT_CPLD_LPC_REG_FAN_CAP1_OFFSET:
 	case MLXPLAT_CPLD_LPC_REG_FAN_CAP2_OFFSET:
 	case MLXPLAT_CPLD_LPC_REG_FAN_DRW_CAP_OFFSET:
+	case MLXPLAT_CPLD_LPC_REG_TACHO_SPEED_OFFSET:
 		return true;
 	}
 	return false;