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

From: Robert Hancock <robert.hancock@calian.com>
To: "michal.simek@xilinx.com" <michal.simek@xilinx.com>
Cc: "chiragp@xilinx.com" <chiragp@xilinx.com>,
	"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Subject: Re: [PATCH] i2c: cadence: Add standard bus recovery support
Date: Wed, 30 Jun 2021 16:40:04 +0000	[thread overview]
Message-ID: <021589cf97b5bf3031d0c72e2ba22b921e504854.camel@calian.com> (raw)
In-Reply-To: <33112554-474c-0740-27b4-42b2f8755daa@xilinx.com>

On Tue, 2021-04-20 at 15:23 +0200, Michal Simek wrote:
> 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>
> 

Any other feedback on this patch? I only saw the ack from Michal. The pinctrl
driver which is needed to make this useful on the ZynqMP platform has now been
merged into mainline (commit 8b242ca700f8043be56542efd8360056358a42ed,
"pinctrl: Add Xilinx ZynqMP pinctrl driver support").

> Thanks,
> Michal
-- 
Robert Hancock
Senior Hardware Designer, Calian Advanced Technologies
www.calian.com