linux-kernel - Re: [PATCH v2 1/2] i2c: qup: add ACPI support

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Date:	Thu, 19 May 2016 14:13:53 -0600
From:	Naveen Kaje <nkaje@...eaurora.org>
To:	Sricharan <sricharan@...eaurora.org>, wsa@...-dreams.de,
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	linux-arm-kernel@...ts.infrared.org, linux-arm-msm@...r.kernel.org,
	rruigrok@...eaurora.org, timur@...eaurora.org, cov@...eaurora.org,
	austinwc@...eaurora.org
Subject: Re: [PATCH v2 1/2] i2c: qup: add ACPI support

Hi Sricharan,

On 5/18/2016 12:04 AM, Sricharan wrote:
> Hi,
>
>> Add support to get the device parameters from ACPI. Assume that the clocks
>> are managed by firmware.
>>
>> Signed-off-by: Naveen Kaje <nkaje@...eaurora.org>
>> ---
>>   drivers/i2c/busses/i2c-qup.c | 59 +++++++++++++++++++++++++++++++++---
>> --------
>>   1 file changed, 44 insertions(+), 15 deletions(-)
>>
> <.snip>
>
>> +/* Default values. Use these if FW query fails */ #define
>> +DEFAULT_CLK_FREQ 100000 #define DEFAULT_SRC_CLK 20000000
>> +
>>   struct qup_i2c_block {
>>   	int	count;
>>   	int	pos;
>> @@ -1360,8 +1365,8 @@ static int qup_i2c_probe(struct platform_device
>> *pdev)
>>   	struct resource *res;
>>   	u32 io_mode, hw_ver, size;
>>   	int ret, fs_div, hs_div;
>> -	int src_clk_freq;
>> -	u32 clk_freq = 100000;
>> +	u32 src_clk_freq = 0;
>> +	u32 clk_freq = 0;
>>   	int blocks;
>>
>>   	qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL); @@ -
>> 1372,7 +1377,12 @@ static int qup_i2c_probe(struct platform_device *pdev)
>>   	init_completion(&qup->xfer);
>>   	platform_set_drvdata(pdev, qup);
>>
>> -	of_property_read_u32(node, "clock-frequency", &clk_freq);
>> +	ret = device_property_read_u32(qup->dev, "clock-frequency",
>> &clk_freq);
>> +	if (ret) {
>> +		dev_warn(qup->dev, "using default clock-frequency %d",
>> +			DEFAULT_CLK_FREQ);
>> +		clk_freq = DEFAULT_CLK_FREQ;
>> +	}
>>
>>   	if (of_device_is_compatible(pdev->dev.of_node, "qcom,i2c-qup-
>> v1.1.1")) {
>>   		qup->adap.algo = &qup_i2c_algo;
>> @@ -1454,20 +1464,31 @@ nodma:
>>   		return qup->irq;
>>   	}
>>
>> -	qup->clk = devm_clk_get(qup->dev, "core");
>> -	if (IS_ERR(qup->clk)) {
>> -		dev_err(qup->dev, "Could not get core clock\n");
>> -		return PTR_ERR(qup->clk);
>> -	}
>> +	if (ACPI_HANDLE(qup->dev)) {
>> +		ret = device_property_read_u32(qup->dev,
>> +				"src-clock-hz", &src_clk_freq);
>> +		if (ret) {
>> +			dev_warn(qup->dev, "using default src-clock-hz %d",
>> +				DEFAULT_SRC_CLK);
>> +			src_clk_freq = DEFAULT_SRC_CLK;
>> +		}
>> +		ACPI_COMPANION_SET(&qup->adap.dev,
>> ACPI_COMPANION(qup->dev));
>> +	} else {
>> +		qup->clk = devm_clk_get(qup->dev, "core");
>> +		if (IS_ERR(qup->clk)) {
>> +			dev_err(qup->dev, "Could not get core clock\n");
>> +			return PTR_ERR(qup->clk);
>> +		}
>>
>> -	qup->pclk = devm_clk_get(qup->dev, "iface");
>> -	if (IS_ERR(qup->pclk)) {
>> -		dev_err(qup->dev, "Could not get iface clock\n");
>> -		return PTR_ERR(qup->pclk);
>> +		qup->pclk = devm_clk_get(qup->dev, "iface");
>> +		if (IS_ERR(qup->pclk)) {
>> +			dev_err(qup->dev, "Could not get iface clock\n");
>> +			return PTR_ERR(qup->pclk);
>> +		}
>> +		qup_i2c_enable_clocks(qup);
>> +		src_clk_freq = clk_get_rate(qup->clk);
>>   	}
>>
>> -	qup_i2c_enable_clocks(qup);
>> -
>>   	/*
>>   	 * Bootloaders might leave a pending interrupt on certain QUP's,
>>   	 * so we reset the core before registering for interrupts.
>> @@ -1514,7 +1535,6 @@ nodma:
>>   	size = QUP_INPUT_FIFO_SIZE(io_mode);
>>   	qup->in_fifo_sz = qup->in_blk_sz * (2 << size);
>>
>> -	src_clk_freq = clk_get_rate(qup->clk);
>>   	fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
>>   	hs_div = 3;
>>   	qup->clk_ctl = (hs_div << 8) | (fs_div & 0xff); @@ -1639,6 +1659,14
>> @@ static const struct of_device_id qup_i2c_dt_match[] = {  };
>> MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);
>>
>> +#if IS_ENABLED(CONFIG_ACPI)
>> +static const struct acpi_device_id qup_i2c_acpi_match[] = {
>> +	{ "QCOM8010"},
>> +	{ },
>> +};
>> +MODULE_DEVICE_TABLE(acpi, qup_i2c_acpi_ids); #endif
>> +
>>   static struct platform_driver qup_i2c_driver = {
>>   	.probe  = qup_i2c_probe,
>>   	.remove = qup_i2c_remove,
>> @@ -1646,6 +1674,7 @@ static struct platform_driver qup_i2c_driver = {
>>   		.name = "i2c_qup",
>>   		.pm = &qup_i2c_qup_pm_ops,
>>   		.of_match_table = qup_i2c_dt_match,
>> +		.acpi_match_table = ACPI_PTR(qup_i2c_acpi_match),
>>   	},
>>   };
>>
>   Reviewed-by: sricharan@...eaurora.org

Thanks for reviewing. I spotted an unused variable, will send a V3 fixing the same.

> Regards,
>   Sricharan
>