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openwrt/target/linux/bcm27xx/patches-6.6/950-0998-i2c-designware-Add-support-for-bus-clear-feature.patch
John Audia b506c964a2 kernel: bump 6.6 to 6.6.61 
Changelog: https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.6.61

Manually rebased:
	bcm27xx/patches-6.6/950-0998-i2c-designware-Add-support-for-bus-clear-feature.patch

All other patches automatically rebased.

Build system: x86/64
Build-tested: x86/64/AMD Cezanne, flogic/xiaomi_redmi-router-ax6000-ubootmod, ramips/tplink_archer-a6-v3
Run-tested: x86/64/AMD Cezanne, flogic/xiaomi_redmi-router-ax6000-ubootmod, ramips/tplink_archer-a6-v3

Signed-off-by: John Audia <therealgraysky@proton.me>
Link: https://github.com/openwrt/openwrt/pull/16959
(cherry picked from commit 487ca61f91)
Link: https://github.com/openwrt/openwrt/pull/17055
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
2024-11-24 22:46:21 +01:00

158 lines
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From 24cb07b0c0724a22e474d12e7c2d5b834bf3b076 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Tue, 26 Mar 2024 15:57:46 +0000
Subject: [PATCH 0998/1085] i2c: designware: Add support for bus clear feature
Newer versions of the DesignWare I2C block support the detection of
stuck signals, and a mechanism to recover from them. Add the required
software support to the driver.
This change was prompted by the observation that reading a single byte
from register 0 of a VEML7700 seems to cause it to issue an ACK too
early, and the controller to complain about losing arbitration. There
is a suspicion that this may be a more widespread problem, but at least
this patch prevents the bus from locking up.
See: https://github.com/raspberrypi/linux/issues/6057
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/i2c/busses/i2c-designware-common.c | 12 ++++++++++++
drivers/i2c/busses/i2c-designware-core.h | 8 ++++++++
drivers/i2c/busses/i2c-designware-master.c | 19 ++++++++++++++++++-
3 files changed, 38 insertions(+), 1 deletion(-)
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -57,6 +57,8 @@ static char *abort_sources[] = {
"slave lost the bus while transmitting data to a remote master",
[ABRT_SLAVE_RD_INTX] =
"incorrect slave-transmitter mode configuration",
+ [ABRT_SLAVE_SDA_STUCK_AT_LOW] =
+ "SDA stuck at low",
};
static int dw_reg_read(void *context, unsigned int reg, unsigned int *val)
@@ -609,8 +611,16 @@ int i2c_dw_wait_bus_not_busy(struct dw_i
int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
{
unsigned long abort_source = dev->abort_source;
+ unsigned int reg;
int i;
+ if (abort_source & DW_IC_TX_ABRT_SLAVE_SDA_STUCK_AT_LOW) {
+ regmap_write(dev->map, DW_IC_ENABLE,
+ DW_IC_ENABLE_ENABLE | DW_IC_ENABLE_BUS_RECOVERY);
+ regmap_read_poll_timeout(dev->map, DW_IC_ENABLE, reg,
+ !(reg & DW_IC_ENABLE_BUS_RECOVERY),
+ 1100, 200000);
+ }
if (abort_source & DW_IC_TX_ABRT_NOACK) {
for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
dev_dbg(dev->dev,
@@ -625,6 +635,8 @@ int i2c_dw_handle_tx_abort(struct dw_i2c
return -EAGAIN;
else if (abort_source & DW_IC_TX_ABRT_GCALL_READ)
return -EINVAL; /* wrong msgs[] data */
+ else if (abort_source & DW_IC_TX_ABRT_SLAVE_SDA_STUCK_AT_LOW)
+ return -EREMOTEIO;
else
return -EIO;
}
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -79,9 +79,12 @@
#define DW_IC_TX_ABRT_SOURCE 0x80
#define DW_IC_ENABLE_STATUS 0x9c
#define DW_IC_CLR_RESTART_DET 0xa8
+#define DW_IC_SCL_STUCK_AT_LOW_TIMEOUT 0xac
+#define DW_IC_SDA_STUCK_AT_LOW_TIMEOUT 0xb0
#define DW_IC_COMP_PARAM_1 0xf4
#define DW_IC_COMP_VERSION 0xf8
#define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A /* "111*" == v1.11* */
+#define DW_IC_BUS_CLEAR_MIN_VERS 0x3230302A /* "200*" == v2.00* */
#define DW_IC_COMP_TYPE 0xfc
#define DW_IC_COMP_TYPE_VALUE 0x44570140 /* "DW" + 0x0140 */
@@ -111,6 +114,7 @@
#define DW_IC_ENABLE_ENABLE BIT(0)
#define DW_IC_ENABLE_ABORT BIT(1)
+#define DW_IC_ENABLE_BUS_RECOVERY BIT(3)
#define DW_IC_STATUS_ACTIVITY BIT(0)
#define DW_IC_STATUS_TFE BIT(2)
@@ -118,6 +122,7 @@
#define DW_IC_STATUS_MASTER_ACTIVITY BIT(5)
#define DW_IC_STATUS_SLAVE_ACTIVITY BIT(6)
#define DW_IC_STATUS_MASTER_HOLD_TX_FIFO_EMPTY BIT(7)
+#define DW_IC_STATUS_SDA_STUCK_NOT_RECOVERED BIT(11)
#define DW_IC_SDA_HOLD_RX_SHIFT 16
#define DW_IC_SDA_HOLD_RX_MASK GENMASK(23, 16)
@@ -165,6 +170,7 @@
#define ABRT_SLAVE_FLUSH_TXFIFO 13
#define ABRT_SLAVE_ARBLOST 14
#define ABRT_SLAVE_RD_INTX 15
+#define ABRT_SLAVE_SDA_STUCK_AT_LOW 17
#define DW_IC_TX_ABRT_7B_ADDR_NOACK BIT(ABRT_7B_ADDR_NOACK)
#define DW_IC_TX_ABRT_10ADDR1_NOACK BIT(ABRT_10ADDR1_NOACK)
@@ -180,6 +186,7 @@
#define DW_IC_RX_ABRT_SLAVE_RD_INTX BIT(ABRT_SLAVE_RD_INTX)
#define DW_IC_RX_ABRT_SLAVE_ARBLOST BIT(ABRT_SLAVE_ARBLOST)
#define DW_IC_RX_ABRT_SLAVE_FLUSH_TXFIFO BIT(ABRT_SLAVE_FLUSH_TXFIFO)
+#define DW_IC_TX_ABRT_SLAVE_SDA_STUCK_AT_LOW BIT(ABRT_SLAVE_SDA_STUCK_AT_LOW)
#define DW_IC_TX_ABRT_NOACK (DW_IC_TX_ABRT_7B_ADDR_NOACK | \
DW_IC_TX_ABRT_10ADDR1_NOACK | \
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -212,6 +212,7 @@ static int i2c_dw_set_timings_master(str
*/
static int i2c_dw_init_master(struct dw_i2c_dev *dev)
{
+ unsigned int timeout = 0;
int ret;
ret = i2c_dw_acquire_lock(dev);
@@ -235,6 +236,17 @@ static int i2c_dw_init_master(struct dw_
regmap_write(dev->map, DW_IC_HS_SCL_LCNT, dev->hs_lcnt);
}
+ if (dev->master_cfg & DW_IC_CON_BUS_CLEAR_CTRL) {
+ /* Set a sensible timeout if not already configured */
+ regmap_read(dev->map, DW_IC_SDA_STUCK_AT_LOW_TIMEOUT, &timeout);
+ if (timeout == ~0) {
+ /* Use 10ms as a timeout, which is 1000 cycles at 100kHz */
+ timeout = i2c_dw_clk_rate(dev) * 10; /* clock rate is in kHz */
+ regmap_write(dev->map, DW_IC_SDA_STUCK_AT_LOW_TIMEOUT, timeout);
+ regmap_write(dev->map, DW_IC_SCL_STUCK_AT_LOW_TIMEOUT, timeout);
+ }
+ }
+
/* Write SDA hold time if supported */
if (dev->sda_hold_time)
regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time);
@@ -1071,6 +1083,7 @@ int i2c_dw_probe_master(struct dw_i2c_de
struct i2c_adapter *adap = &dev->adapter;
unsigned long irq_flags;
unsigned int ic_con;
+ unsigned int id_ver;
int ret;
init_completion(&dev->cmd_complete);
@@ -1106,7 +1119,11 @@ int i2c_dw_probe_master(struct dw_i2c_de
if (ret)
return ret;
- if (ic_con & DW_IC_CON_BUS_CLEAR_CTRL)
+ ret = regmap_read(dev->map, DW_IC_COMP_VERSION, &id_ver);
+ if (ret)
+ return ret;
+
+ if (ic_con & DW_IC_CON_BUS_CLEAR_CTRL || id_ver >= DW_IC_BUS_CLEAR_MIN_VERS)
dev->master_cfg |= DW_IC_CON_BUS_CLEAR_CTRL;
ret = dev->init(dev);
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