Fix i2c for Sunxi-R8

0001-i2c-mv64xxx-Add-atomic_xfer-method-to-driver.patch

From 805fec0c5aa2f1c11d7859a3995ae0e5c74e3355 Mon Sep 17 00:00:00 2001
From: Chris Morgan <[email protected]>
Date: Mon, 28 Mar 2022 15:53:11 -0500
Subject: [PATCH] i2c: mv64xxx: Add atomic_xfer method to driver

Add an atomic_xfer method to the driver so that it behaves correctly
when controlling a PMIC that is responsible for device shutdown.

The atomic_xfer method added is similar to the one from the i2c-rk3x
driver. When running an atomic_xfer is sets a bool flag in the driver
data, doesn't unmask the interrupt upon transfer start, and invokes
the IRQ handler manually while waiting for pending transfers to
complete.

Signed-off-by: Chris Morgan <[email protected]>
---
 drivers/i2c/busses/i2c-mv64xxx.c | 54 +++++++++++++++++++++++++++-----
 1 file changed, 47 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 424c53e4c513..af3b594fa153 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -150,6 +150,7 @@ struct mv64xxx_i2c_data {
 	/* Clk div is 2 to the power n, not 2 to the power n + 1 */
 	bool			clk_n_base_0;
 	struct i2c_bus_recovery_info	rinfo;
+	bool			atomic;
 };
 
 static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = {
@@ -179,7 +180,10 @@ mv64xxx_i2c_prepare_for_io(struct mv64xxx_i2c_data *drv_data,
 	u32	dir = 0;
 
 	drv_data->cntl_bits = MV64XXX_I2C_REG_CONTROL_ACK |
-		MV64XXX_I2C_REG_CONTROL_INTEN | MV64XXX_I2C_REG_CONTROL_TWSIEN;
+			      MV64XXX_I2C_REG_CONTROL_TWSIEN;
+
+	if (!drv_data->atomic)
+		drv_data->cntl_bits |= MV64XXX_I2C_REG_CONTROL_INTEN;
 
 	if (msg->flags & I2C_M_RD)
 		dir = 1;
@@ -409,7 +413,8 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
 	case MV64XXX_I2C_ACTION_RCV_DATA_STOP:
 		drv_data->msg->buf[drv_data->byte_posn++] =
 			readl(drv_data->reg_base + drv_data->reg_offsets.data);
-		drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
+		if(!drv_data->atomic)
+			drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
 		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,
 			drv_data->reg_base + drv_data->reg_offsets.control);
 		drv_data->block = 0;
@@ -427,7 +432,8 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
 		drv_data->rc = -EIO;
 		fallthrough;
 	case MV64XXX_I2C_ACTION_SEND_STOP:
-		drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
+		if(!drv_data->atomic)
+			drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
 		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,
 			drv_data->reg_base + drv_data->reg_offsets.control);
 		drv_data->block = 0;
@@ -575,6 +581,17 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
 		spin_unlock_irqrestore(&drv_data->lock, flags);
 }
 
+static void mv64xxx_i2c_wait_polling(struct mv64xxx_i2c_data *drv_data)
+{
+	ktime_t timeout = ktime_add_ms(ktime_get(), drv_data->adapter.timeout);
+
+	while (READ_ONCE(drv_data->block) &&
+	       ktime_compare(ktime_get(), timeout) < 0) {
+		udelay(5);
+		mv64xxx_i2c_intr(0, drv_data);
+	}
+}
+
 static int
 mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg,
 				int is_last)
@@ -590,7 +607,11 @@ mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg,
 	mv64xxx_i2c_send_start(drv_data);
 	spin_unlock_irqrestore(&drv_data->lock, flags);
 
-	mv64xxx_i2c_wait_for_completion(drv_data);
+	if (!drv_data->atomic)
+		mv64xxx_i2c_wait_for_completion(drv_data);
+	else
+		mv64xxx_i2c_wait_polling(drv_data);
+
 	return drv_data->rc;
 }
 
@@ -716,8 +737,8 @@ mv64xxx_i2c_functionality(struct i2c_adapter *adap)
 	return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
 }
 
-static int
-mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+static int mv64xxx_i2c_xfer_core(struct i2c_adapter *adap,
+				 struct i2c_msg msgs[], int num)
 {
 	struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
 	int rc, ret = num;
@@ -730,7 +751,7 @@ mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	drv_data->msgs = msgs;
 	drv_data->num_msgs = num;
 
-	if (mv64xxx_i2c_can_offload(drv_data))
+	if (mv64xxx_i2c_can_offload(drv_data) && !drv_data->atomic)
 		rc = mv64xxx_i2c_offload_xfer(drv_data);
 	else
 		rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[0], num == 1);
@@ -747,8 +768,27 @@ mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	return ret;
 }
 
+static int
+mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
+
+	drv_data->atomic = 0;
+	return mv64xxx_i2c_xfer_core(adap, msgs, num);
+}
+
+static int mv64xxx_i2c_xfer_atomic(struct i2c_adapter *adap,
+				   struct i2c_msg msgs[], int num)
+{
+	struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
+
+	drv_data->atomic = 1;
+	return mv64xxx_i2c_xfer_core(adap, msgs, num);
+}
+
 static const struct i2c_algorithm mv64xxx_i2c_algo = {
 	.master_xfer = mv64xxx_i2c_xfer,
+	.master_xfer_atomic = mv64xxx_i2c_xfer_atomic,
 	.functionality = mv64xxx_i2c_functionality,
 };
 
-- 
2.25.1

0001-i2c-mv64xxx-Remove-shutdown-method-from-driver.patch

From 9d1d8e9781e2756c4c3c5c9ee292c7b286dd6fd3 Mon Sep 17 00:00:00 2001
From: Chris Morgan <[email protected]>
Date: Fri, 25 Mar 2022 12:58:23 -0500
Subject: [PATCH] i2c: mv64xxx: Remove shutdown method from driver

When I attempt to shut down (or reboot) my R8 based NTC CHIP with this
i2c driver I get the following error: "i2c i2c-0: mv64xxx: I2C bus
locked, block: 1, time_left: 0". Reboots are successful but shutdowns
freeze. If I comment out the shutdown routine the device both reboots
and shuts down successfully without receiving this error (however it
does receive a warning of missing atomic_xfer).

It appears that very few i2c drivers have a shutdown method, I assume
because these devices are often used to communicate with PMICs (such
as in my case with the R8 based NTC CHIP). I'm proposing we simply
remove this method so long as it doesn't cause trouble for others
downstream. I'll work on an atomic_xfer method and submit that in
a different patch.

Signed-off-by: Chris Morgan <[email protected]>
---
 drivers/i2c/busses/i2c-mv64xxx.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 5c8e94b6cdb5..424c53e4c513 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -1047,14 +1047,6 @@ mv64xxx_i2c_remove(struct platform_device *pd)
 	return 0;
 }
 
-static void
-mv64xxx_i2c_shutdown(struct platform_device *pd)
-{
-	pm_runtime_disable(&pd->dev);
-	if (!pm_runtime_status_suspended(&pd->dev))
-		mv64xxx_i2c_runtime_suspend(&pd->dev);
-}
-
 static const struct dev_pm_ops mv64xxx_i2c_pm_ops = {
 	SET_RUNTIME_PM_OPS(mv64xxx_i2c_runtime_suspend,
 			   mv64xxx_i2c_runtime_resume, NULL)
@@ -1065,7 +1057,6 @@ static const struct dev_pm_ops mv64xxx_i2c_pm_ops = {
 static struct platform_driver mv64xxx_i2c_driver = {
 	.probe	= mv64xxx_i2c_probe,
 	.remove	= mv64xxx_i2c_remove,
-	.shutdown = mv64xxx_i2c_shutdown,
 	.driver	= {
 		.name	= MV64XXX_I2C_CTLR_NAME,
 		.pm     = &mv64xxx_i2c_pm_ops,
-- 
2.25.1