diff mbox series

[v3,4/5] i2c: nvidia-gpu: resume ccgx i2c client

Message ID 20190522183142.11061-5-ajayg@nvidia.com (mailing list archive)
State Superseded
Headers show
Series usb: typec: ucsi: ccg: add runtime pm support | expand

Commit Message

Ajay Gupta May 22, 2019, 6:31 p.m. UTC 
From: Ajay Gupta <ajayg@nvidia.com>

Cypress USB Type-C CCGx controller firmware version 3.1.10
(which is being used in many NVIDIA GPU cards) has known issue of
not triggering interrupt when a USB device is hot plugged to runtime
resume the controller. If any GPU card gets latest kernel with runtime
pm support but does not get latest fixed firmware then also it should
continue to work and therefore a workaround is required to check for
any connector change event

The workaround is to request runtime resume of i2c client
which is UCSI Cypress CCGx driver. CCG driver will call the ISR
for any connector change event only if NVIDIA GPU has old
CCG firmware with the known issue.

Signed-off-by: Ajay Gupta <ajayg@nvidia.com>
---
Changes from v2->v3: None

 drivers/i2c/busses/i2c-nvidia-gpu.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Comments

Wolfram Sang May 25, 2019, 7:58 p.m. UTC | #1 
On Wed, May 22, 2019 at 11:31:41AM -0700, Ajay Gupta wrote:
> From: Ajay Gupta <ajayg@nvidia.com>
> 
> Cypress USB Type-C CCGx controller firmware version 3.1.10
> (which is being used in many NVIDIA GPU cards) has known issue of
> not triggering interrupt when a USB device is hot plugged to runtime
> resume the controller. If any GPU card gets latest kernel with runtime
> pm support but does not get latest fixed firmware then also it should
> continue to work and therefore a workaround is required to check for
> any connector change event
> 
> The workaround is to request runtime resume of i2c client
> which is UCSI Cypress CCGx driver. CCG driver will call the ISR
> for any connector change event only if NVIDIA GPU has old
> CCG firmware with the known issue.
> 
> Signed-off-by: Ajay Gupta <ajayg@nvidia.com>

Can't say if this is a valid workaround but here is my ack for modifying
the I2C realm:

Acked-by: Wolfram Sang <wsa@the-dreams.de>
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-nvidia-gpu.c b/drivers/i2c/busses/i2c-nvidia-gpu.c
index 28fee85135ac..957b39c9760f 100644
--- a/drivers/i2c/busses/i2c-nvidia-gpu.c
+++ b/drivers/i2c/busses/i2c-nvidia-gpu.c
@@ -51,6 +51,7 @@  struct gpu_i2c_dev {
 	void __iomem *regs;
 	struct i2c_adapter adapter;
 	struct i2c_board_info *gpu_ccgx_ucsi;
+	struct i2c_client *ccgx_client;
 };
 
 static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd)
@@ -271,8 +272,6 @@  static const struct property_entry ccgx_props[] = {
 
 static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq)
 {
-	struct i2c_client *ccgx_client;
-
 	i2cd->gpu_ccgx_ucsi = devm_kzalloc(i2cd->dev,
 					   sizeof(*i2cd->gpu_ccgx_ucsi),
 					   GFP_KERNEL);
@@ -284,8 +283,8 @@  static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq)
 	i2cd->gpu_ccgx_ucsi->addr = 0x8;
 	i2cd->gpu_ccgx_ucsi->irq = irq;
 	i2cd->gpu_ccgx_ucsi->properties = ccgx_props;
-	ccgx_client = i2c_new_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi);
-	if (!ccgx_client)
+	i2cd->ccgx_client = i2c_new_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi);
+	if (!i2cd->ccgx_client)
 		return -ENODEV;
 
 	return 0;
@@ -375,6 +374,13 @@  static __maybe_unused int gpu_i2c_resume(struct device *dev)
 	struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev);
 
 	gpu_enable_i2c_bus(i2cd);
+	/*
+	 * Runtime resume ccgx client so that it can see for any
+	 * connector change event. Old ccg firmware has known
+	 * issue of not triggering interrupt when a device is
+	 * connected to runtime resume the controller.
+	 */
+	pm_request_resume(&i2cd->ccgx_client->dev);
 	return 0;
 }