Re: [PATCH] i2c: cadence: Add standard bus recovery support

[Michal Simek <michal.simek@xilinx.com>]

Hi,

On 4/16/21 1:25 AM, Robert Hancock wrote:
> Hook up the standard GPIO/pinctrl-based recovery support for this
> driver.
> 
> Based on a patch "i2c: cadence: Recover bus after controller reset" by
> Chirag Parekh in the Xilinx kernel Git tree, but simplified to make use
> of more common code.
> 
> Cc: Chirag Parekh <chiragp@xilinx.com>
> Signed-off-by: Robert Hancock <robert.hancock@calian.com>
> ---
>  drivers/i2c/busses/i2c-cadence.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
> index c1bbc4caeb5c..d017bc64e759 100644
> --- a/drivers/i2c/busses/i2c-cadence.c
> +++ b/drivers/i2c/busses/i2c-cadence.c
> @@ -178,6 +178,7 @@ enum cdns_i2c_slave_state {
>   * @clk:		Pointer to struct clk
>   * @clk_rate_change_nb:	Notifier block for clock rate changes
>   * @quirks:		flag for broken hold bit usage in r1p10
> + * @rinfo:		Structure holding recovery information.
>   * @ctrl_reg_diva_divb: value of fields DIV_A and DIV_B from CR register
>   * @slave:		Registered slave instance.
>   * @dev_mode:		I2C operating role(master/slave).
> @@ -202,6 +203,7 @@ struct cdns_i2c {
>  	struct clk *clk;
>  	struct notifier_block clk_rate_change_nb;
>  	u32 quirks;
> +	struct i2c_bus_recovery_info rinfo;
>  #if IS_ENABLED(CONFIG_I2C_SLAVE)
>  	u16 ctrl_reg_diva_divb;
>  	struct i2c_client *slave;
> @@ -752,6 +754,7 @@ static int cdns_i2c_process_msg(struct cdns_i2c *id, struct i2c_msg *msg,
>  	/* Wait for the signal of completion */
>  	time_left = wait_for_completion_timeout(&id->xfer_done, adap->timeout);
>  	if (time_left == 0) {
> +		i2c_recover_bus(adap);
>  		cdns_i2c_master_reset(adap);
>  		dev_err(id->adap.dev.parent,
>  				"timeout waiting on completion\n");
> @@ -1212,6 +1215,7 @@ static int cdns_i2c_probe(struct platform_device *pdev)
>  	id->adap.retries = 3;		/* Default retry value. */
>  	id->adap.algo_data = id;
>  	id->adap.dev.parent = &pdev->dev;
> +	id->adap.bus_recovery_info = &id->rinfo;
>  	init_completion(&id->xfer_done);
>  	snprintf(id->adap.name, sizeof(id->adap.name),
>  		 "Cadence I2C at %08lx", (unsigned long)r_mem->start);
> 

My colleague sent pinctrl driver for ZynqMP already. This driver can be
used on Zynq where pinctrl driver already exists upstream.

It looks quite nice.

Acked-by: Michal Simek <michal.simek@xilinx.com>

Thanks,
Michal