[PATCH v4 1/2] i2c: qup: add ACPI support

[Mika Westerberg]

On Sat, Jun 18, 2016 at 04:10:34PM +0200, Wolfram Sang wrote:
> On Wed, Jun 08, 2016 at 12:19:44PM -0600, Austin Christ wrote:
> > From: Naveen Kaje <nkaje at codeaurora.org>
> > 
> > Add support to get the device parameters from ACPI. Assume
> > that the clocks are managed by firmware.
> 
> Adding Mika to CC: Can you have a look at the ACPI binding? Looks ok to
> me...
> 
> > 
> > Signed-off-by: Naveen Kaje <nkaje at codeaurora.org>
> > Signed-off-by: Austin Christ <austinwc at codeaurora.org>
> > Reviewed-by: sricharan at codeaurora.org
> 
> Please add a name before the email address
> 
> > ---
> >  drivers/i2c/busses/i2c-qup.c | 59 ++++++++++++++++++++++++++++++++------------
> >  1 file changed, 43 insertions(+), 16 deletions(-)
> > 
> > Changes:
> > - v4:
> >  - remove warning for fall back to default clock frequency
> > - v3:
> >  - clean up unused variable
> > - v2:
> >  - clean up redundant checks and variables
> > 
> > diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> > index dddd4da..0f23d58 100644
> > --- a/drivers/i2c/busses/i2c-qup.c
> > +++ b/drivers/i2c/busses/i2c-qup.c
> > @@ -29,6 +29,7 @@
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_runtime.h>
> >  #include <linux/scatterlist.h>
> > +#include <linux/acpi.h>
> 
> Keep includes sorted.
> 
> >  
> >  /* QUP Registers */
> >  #define QUP_CONFIG		0x000
> > @@ -132,6 +133,10 @@
> >  /* Max timeout in ms for 32k bytes */
> >  #define TOUT_MAX			300
> >  
> > +/* 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;
> > @@ -1354,14 +1359,13 @@ static void qup_i2c_disable_clocks(struct qup_i2c_dev *qup)
> >  static int qup_i2c_probe(struct platform_device *pdev)
> >  {
> >  	static const int blk_sizes[] = {4, 16, 32};
> > -	struct device_node *node = pdev->dev.of_node;
> >  	struct qup_i2c_dev *qup;
> >  	unsigned long one_bit_t;
> >  	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 = DEFAULT_CLK_FREQ;
> >  	int blocks;
> >  
> >  	qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
> > @@ -1372,7 +1376,11 @@ 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_notice(qup->dev, "using default clock-frequency %d",
> > +			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 +1462,31 @@ 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)) {

Use has_acpi_companion() if you need to.

> > +		ret = device_property_read_u32(qup->dev,
> > +				"src-clock-hz", &src_clk_freq);

Alternatively you can make qup_i2c_acpi_probe() which creates clock for
you based on the ACPI ID of the device. Then you do not need to have
these custom properties just because ACPI does not have native support
for clocks.

Ideally if one uses device_property_* API it should not need to
distinguish between DT/ACPI/whatnot.

> > +		if (ret) {
> > +			dev_warn(qup->dev, "using default src-clock-hz %d",
> > +				DEFAULT_SRC_CLK);

Why this is warning?

> > +			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 +1533,6 @@ 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 +1657,14 @@ 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 +1672,7 @@ 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),
> >  	},
> >  };
> >  
> > -- 
> > Qualcomm Innovation Center, Inc.
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project.
> >