Revert "smart_battery: add smbus error checking support"

This reverts commit daccb3adea9394116d7ab2c807e4a360cb5a93a1.

Reason for revert: <INSERT REASONING HERE>

broke USB-C charging.  all we get now is:

2019-10-30 01:26:15 New chg p0[49.441303 CL: p0 s2 i500 v5000]
2019-10-30 01:26:16 C0 st5
2019-10-30 01:26:16 C0 Req [1] 5000mV 3000mA
2019-10-30 01:26:16 New chg p0[50.305144 CL: p0 s0 i500 v5000]
2019-10-30 01:26:16 C0 HARD RST RX
2019-10-30 01:26:16 C0 st4
2019-10-30 01:26:16 New chg p0[50.354280 CL: p0 s2 i500 v5000]
2019-10-30 01:26:17 C0 st5
2019-10-30 01:26:17 C0 Req [1] 5000mV 3000mA
...

Original change's description:
> smart_battery: add smbus error checking support
> 
> Jacuzzi/Kodama has a unstable software controlled i2c bus, its data
> transmission may be interrupted by other higher priority tasks and
> causes device timeout.
> 
> If timeout happens when ec is reading data, it has no knowledge about
> what's happening on slave, and keep receiving bad data (0xFF's) until
> end. The standard i2c/smbus error handling mechanism can not handle this
> case, so we need the error checking feature from smbus 1.1 to ensure our
> received data is correct.
> 
> This CL adds the error checking (PEC) functions to i2c and smart battery
> module.
> 
> BUG=b:138415463
> TEST=On kodama, enable CONFIG_CMD_I2C_STRESS_TEST,
>      no failure after 100k read/writes.
>      test code at CL:1865054
> BRANCH=master
> 
> Change-Id: Ibb9ad3aa03d7690a08f59c617c2cd9c1b9cb0ff3
> Signed-off-by: Ting Shen <phoenixshen@google.com>
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1827138
> Reviewed-by: Denis Brockus <dbrockus@chromium.org>
> Tested-by: Ting Shen <phoenixshen@chromium.org>
> Commit-Queue: Ting Shen <phoenixshen@chromium.org>

Bug: b:138415463
Change-Id: Ibd8a512dd6d43cca95628f698e7a66a695b7fc59
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1889435
Reviewed-by: Caveh Jalali <caveh@google.com>
Reviewed-by: Ting Shen <phoenixshen@chromium.org>
Commit-Queue: Caveh Jalali <caveh@google.com>
Tested-by: Caveh Jalali <caveh@google.com>

1 files changed, 8 insertions, 43 deletions

diff --git a/driver/battery/smart.c b/driver/battery/smart.c
index 0d3d377ff8..89a99623af 100644
--- a/driver/battery/smart.c
+++ b/driver/battery/smart.c
@@ -21,32 +21,8 @@
 
 static int fake_state_of_charge = -1;
 
-static int battery_supports_pec(void)
-{
-	static int supports_pec = -1;
-
-	if (!IS_ENABLED(CONFIG_SMBUS_PEC))
-		return 0;
-
-	if (supports_pec < 0) {
-		int spec_info;
-		int rv = i2c_read16(I2C_PORT_BATTERY, BATTERY_ADDR_FLAGS,
-				    SB_SPECIFICATION_INFO, &spec_info);
-		/* failed, assuming not support and try again later */
-		if (rv)
-			return 0;
-
-		supports_pec = (BATTERY_SPEC_VERSION(spec_info) ==
-				BATTERY_SPEC_VER_1_1_WITH_PEC);
-		CPRINTS("battery supports pec: %d", supports_pec);
-	}
-	return supports_pec;
-}
-
 test_mockable int sb_read(int cmd, int *param)
 {
-	uint16_t addr_flags = BATTERY_ADDR_FLAGS;
-
 #ifdef CONFIG_BATTERY_CUT_OFF
 	/*
 	 * Some batteries would wake up after cut-off if we talk to it.
@@ -54,16 +30,13 @@ test_mockable int sb_read(int cmd, int *param)
 	if (battery_is_cut_off())
 		return EC_RES_ACCESS_DENIED;
 #endif
-	if (battery_supports_pec())
-		addr_flags |= I2C_FLAG_PEC;
 
-	return i2c_read16(I2C_PORT_BATTERY, addr_flags, cmd, param);
+	return i2c_read16(I2C_PORT_BATTERY, BATTERY_ADDR_FLAGS,
+			  cmd, param);
 }
 
 test_mockable int sb_write(int cmd, int param)
 {
-	uint16_t addr_flags = BATTERY_ADDR_FLAGS;
-
 #ifdef CONFIG_BATTERY_CUT_OFF
 	/*
 	 * Some batteries would wake up after cut-off if we talk to it.
@@ -71,16 +44,13 @@ test_mockable int sb_write(int cmd, int param)
 	if (battery_is_cut_off())
 		return EC_RES_ACCESS_DENIED;
 #endif
-	if (battery_supports_pec())
-		addr_flags |= I2C_FLAG_PEC;
 
-	return i2c_write16(I2C_PORT_BATTERY, addr_flags, cmd, param);
+	return i2c_write16(I2C_PORT_BATTERY, BATTERY_ADDR_FLAGS,
+			   cmd, param);
 }
 
 int sb_read_string(int offset, uint8_t *data, int len)
 {
-	uint16_t addr_flags = BATTERY_ADDR_FLAGS;
-
 #ifdef CONFIG_BATTERY_CUT_OFF
 	/*
 	 * Some batteries would wake up after cut-off if we talk to it.
@@ -88,10 +58,9 @@ int sb_read_string(int offset, uint8_t *data, int len)
 	if (battery_is_cut_off())
 		return EC_RES_ACCESS_DENIED;
 #endif
-	if (battery_supports_pec())
-		addr_flags |= I2C_FLAG_PEC;
 
-	return i2c_read_string(I2C_PORT_BATTERY, addr_flags, offset, data, len);
+	return i2c_read_string(I2C_PORT_BATTERY, BATTERY_ADDR_FLAGS,
+			       offset, data, len);
 }
 
 int sb_read_mfgacc(int cmd, int block, uint8_t *data, int len)
@@ -126,8 +95,6 @@ int sb_read_mfgacc(int cmd, int block, uint8_t *data, int len)
 
 int sb_write_block(int reg, const uint8_t *val, int len)
 {
-	uint16_t addr_flags = BATTERY_ADDR_FLAGS;
-
 #ifdef CONFIG_BATTERY_CUT_OFF
 	/*
 	 * Some batteries would wake up after cut-off if we talk to it.
@@ -136,11 +103,9 @@ int sb_write_block(int reg, const uint8_t *val, int len)
 		return EC_RES_ACCESS_DENIED;
 #endif
 
-	if (battery_supports_pec())
-		addr_flags |= I2C_FLAG_PEC;
-
 	/* TODO: implement smbus_write_block. */
-	return i2c_write_block(I2C_PORT_BATTERY, addr_flags, reg, val, len);
+	return i2c_write_block(I2C_PORT_BATTERY, BATTERY_ADDR_FLAGS,
+			       reg, val, len);
 }
 
 int battery_get_mode(int *mode)