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

[Naveen Kaje]

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 <nk...@codeaurora.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: sricha...@codeaurora.org

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

Regards,
  Sricharan