Re: [PATCH 3/4] media: sunxi-cir: Factor out hardware initialization

[Samuel Holland]

On 1/13/21 8:36 AM, Sean Young wrote:
> On Tue, Jan 12, 2021 at 10:51:31PM -0600, Samuel Holland wrote:
>> In preparation for adding suspend/resume hooks, factor out the hardware
>> initialization from the driver probe/remove functions.
>>
>> The timeout programmed during init is taken from the `struct rc_dev` so
>> it is maintained across an exit/init cycle.
>>
>> This resolves some trivial issues with the probe function: throwing away
>> the error from clk_prepare_enable and using the wrong type for the
>> temporary register value.
>>
>> Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
>> ---
>>  drivers/media/rc/sunxi-cir.c | 128 ++++++++++++++++++++---------------
>>  1 file changed, 74 insertions(+), 54 deletions(-)
>>
>> diff --git a/drivers/media/rc/sunxi-cir.c b/drivers/media/rc/sunxi-cir.c
>> index 48be400421cd..ccb9d6b4225d 100644
>> --- a/drivers/media/rc/sunxi-cir.c
>> +++ b/drivers/media/rc/sunxi-cir.c
>> @@ -169,10 +169,74 @@ static int sunxi_ir_set_timeout(struct rc_dev *rc_dev, unsigned int timeout)
>>  	return 0;
>>  }
>>  
>> +static int sunxi_ir_hw_init(struct device *dev)
>> +{
>> +	struct sunxi_ir *ir = dev_get_drvdata(dev);
>> +	u32 tmp;
>> +	int ret;
>> +
>> +	ret = reset_control_deassert(ir->rst);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = clk_prepare_enable(ir->apb_clk);
>> +	if (ret) {
>> +		dev_err(dev, "failed to enable apb clk\n");
>> +		goto exit_assert_reset;
>> +	}
>> +
>> +	ret = clk_prepare_enable(ir->clk);
>> +	if (ret) {
>> +		dev_err(dev, "failed to enable ir clk\n");
>> +		goto exit_disable_apb_clk;
>> +	}
>> +
>> +	/* Enable CIR Mode */
>> +	writel(REG_CTL_MD, ir->base + SUNXI_IR_CTL_REG);
>> +
>> +	/* Set noise threshold and idle threshold */
>> +	sunxi_ir_set_timeout(ir->rc, ir->rc->timeout);

Initializing ir->rc->timeout in .probe is needed because of this line.
As the changelog mentions, this reprograms the user-configured timeout
after an exit/init (suspend/resume) cycle. It needs some default value
the first time, when called from .probe.

>> +
>> +	/* Invert Input Signal */
>> +	writel(REG_RXCTL_RPPI, ir->base + SUNXI_IR_RXCTL_REG);
>> +
>> +	/* Clear All Rx Interrupt Status */
>> +	writel(REG_RXSTA_CLEARALL, ir->base + SUNXI_IR_RXSTA_REG);
>> +
>> +	/*
>> +	 * Enable IRQ on overflow, packet end, FIFO available with trigger
>> +	 * level
>> +	 */
>> +	writel(REG_RXINT_ROI_EN | REG_RXINT_RPEI_EN |
>> +	       REG_RXINT_RAI_EN | REG_RXINT_RAL(ir->fifo_size / 2 - 1),
>> +	       ir->base + SUNXI_IR_RXINT_REG);
>> +
>> +	/* Enable IR Module */
>> +	tmp = readl(ir->base + SUNXI_IR_CTL_REG);
>> +	writel(tmp | REG_CTL_GEN | REG_CTL_RXEN, ir->base + SUNXI_IR_CTL_REG);
>> +
>> +	return 0;
>> +
>> +exit_disable_apb_clk:
>> +	clk_disable_unprepare(ir->apb_clk);
>> +exit_assert_reset:
>> +	reset_control_assert(ir->rst);
>> +
>> +	return ret;
>> +}
>> +
>> +static void sunxi_ir_hw_exit(struct device *dev)
>> +{
>> +	struct sunxi_ir *ir = dev_get_drvdata(dev);
>> +
>> +	clk_disable_unprepare(ir->clk);
>> +	clk_disable_unprepare(ir->apb_clk);
>> +	reset_control_assert(ir->rst);
>> +}
>> +
>>  static int sunxi_ir_probe(struct platform_device *pdev)
>>  {
>>  	int ret = 0;
>> -	unsigned long tmp = 0;
>>  
>>  	struct device *dev = &pdev->dev;
>>  	struct device_node *dn = dev->of_node;
>> @@ -213,43 +277,26 @@ static int sunxi_ir_probe(struct platform_device *pdev)
>>  		ir->rst = devm_reset_control_get_exclusive(dev, NULL);
>>  		if (IS_ERR(ir->rst))
>>  			return PTR_ERR(ir->rst);
>> -		ret = reset_control_deassert(ir->rst);
>> -		if (ret)
>> -			return ret;
>>  	}
>>  
>>  	ret = clk_set_rate(ir->clk, b_clk_freq);
>>  	if (ret) {
>>  		dev_err(dev, "set ir base clock failed!\n");
>> -		goto exit_reset_assert;
>> +		return ret;
>>  	}
>>  	dev_dbg(dev, "set base clock frequency to %d Hz.\n", b_clk_freq);
>>  
>> -	if (clk_prepare_enable(ir->apb_clk)) {
>> -		dev_err(dev, "try to enable apb_ir_clk failed\n");
>> -		ret = -EINVAL;
>> -		goto exit_reset_assert;
>> -	}
>> -
>> -	if (clk_prepare_enable(ir->clk)) {
>> -		dev_err(dev, "try to enable ir_clk failed\n");
>> -		ret = -EINVAL;
>> -		goto exit_clkdisable_apb_clk;
>> -	}
>> -
>>  	/* IO */
>>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>  	ir->base = devm_ioremap_resource(dev, res);
>>  	if (IS_ERR(ir->base)) {
>> -		ret = PTR_ERR(ir->base);
>> -		goto exit_clkdisable_clk;
>> +		return PTR_ERR(ir->base);
>>  	}
>>  
>>  	ir->rc = rc_allocate_device(RC_DRIVER_IR_RAW);
>>  	if (!ir->rc) {
>>  		dev_err(dev, "failed to allocate device\n");
>> -		ret = -ENOMEM;
>> -		goto exit_clkdisable_clk;
>> +		return -ENOMEM;
>>  	}
>>  
>>  	ir->rc->priv = ir;
>> @@ -265,6 +312,7 @@ static int sunxi_ir_probe(struct platform_device *pdev)
>>  	ir->rc->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
>>  	/* Frequency after IR internal divider with sample period in us */
>>  	ir->rc->rx_resolution = (USEC_PER_SEC / (b_clk_freq / 64));
>> +	ir->rc->timeout = IR_DEFAULT_TIMEOUT;
> 
> Why? This is set from sunxi_ir_set_timeout().

Because it is also sent as an argument to sunxi_ir_set_timeout().

>>  	ir->rc->min_timeout = sunxi_ithr_to_usec(b_clk_freq, 0);
>>  	ir->rc->max_timeout = sunxi_ithr_to_usec(b_clk_freq, 255);
>>  	ir->rc->s_timeout = sunxi_ir_set_timeout;
>> @@ -291,41 +339,15 @@ static int sunxi_ir_probe(struct platform_device *pdev)
>>  		goto exit_free_dev;
>>  	}
>>  
>> -	/* Enable CIR Mode */
>> -	writel(REG_CTL_MD, ir->base+SUNXI_IR_CTL_REG);
>> -
>> -	/* Set noise threshold and idle threshold */
>> -	sunxi_ir_set_timeout(ir->rc, IR_DEFAULT_TIMEOUT);

This is where the default timeout was originally programmed.

>> -
>> -	/* Invert Input Signal */
>> -	writel(REG_RXCTL_RPPI, ir->base + SUNXI_IR_RXCTL_REG);
>> -
>> -	/* Clear All Rx Interrupt Status */
>> -	writel(REG_RXSTA_CLEARALL, ir->base + SUNXI_IR_RXSTA_REG);
>> -
>> -	/*
>> -	 * Enable IRQ on overflow, packet end, FIFO available with trigger
>> -	 * level
>> -	 */
>> -	writel(REG_RXINT_ROI_EN | REG_RXINT_RPEI_EN |
>> -	       REG_RXINT_RAI_EN | REG_RXINT_RAL(ir->fifo_size / 2 - 1),
>> -	       ir->base + SUNXI_IR_RXINT_REG);
>> -
>> -	/* Enable IR Module */
>> -	tmp = readl(ir->base + SUNXI_IR_CTL_REG);
>> -	writel(tmp | REG_CTL_GEN | REG_CTL_RXEN, ir->base + SUNXI_IR_CTL_REG);
>> +	ret = sunxi_ir_hw_init(dev);
>> +	if (ret)
>> +		goto exit_free_dev;
>>  
>>  	dev_info(dev, "initialized sunXi IR driver\n");
>>  	return 0;
>>  
>>  exit_free_dev:
>>  	rc_free_device(ir->rc);
>> -exit_clkdisable_clk:
>> -	clk_disable_unprepare(ir->clk);
>> -exit_clkdisable_apb_clk:
>> -	clk_disable_unprepare(ir->apb_clk);
>> -exit_reset_assert:
>> -	reset_control_assert(ir->rst);
>>  
>>  	return ret;
>>  }
>> @@ -334,11 +356,9 @@ static int sunxi_ir_remove(struct platform_device *pdev)
>>  {
>>  	struct sunxi_ir *ir = platform_get_drvdata(pdev);
>>  
>> -	clk_disable_unprepare(ir->clk);
>> -	clk_disable_unprepare(ir->apb_clk);
>> -	reset_control_assert(ir->rst);
>> -
>> +	sunxi_ir_hw_exit(&pdev->dev);
>>  	rc_unregister_device(ir->rc);

I can swap these lines to fix your comment on patch 1.

>> +
>>  	return 0;
>>  }
>>  
>> -- 
>> 2.26.2