linux-kernel - RE: [PATCH v3 1/2] i2c: qup: add ACPI support

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Message-ID: <000001d1b65e$0bfbfde0$23f3f9a0$@codeaurora.org>
Date:	Wed, 25 May 2016 13:48:34 +0530
From:	"Sricharan" <sricharan@...eaurora.org>
To:	"'Austin Christ'" <austinwc@...eaurora.org>,
	<nkaje@...eaurora.org>, <wsa@...-dreams.de>,
	<linux-i2c@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Cc:	<linux-arm-msm@...r.kernel.org>, <timur@...eaurora.org>,
	<rruigrok@...eaurora.org>, <cov@...eaurora.org>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH v3 1/2] i2c: qup: add ACPI support

Hi,

>From: Naveen Kaje <nkaje@...eaurora.org>
>
>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>
>Signed-off-by: Austin Christ <austinwc@...eaurora.org>
>---
> drivers/i2c/busses/i2c-qup.c | 60 ++++++++++++++++++++++++++++++++------------
> 1 file changed, 44 insertions(+), 16 deletions(-)
>
>Changes:
>- 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..ea6ca5f 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>
>
> /* 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 = 0;
> 	int blocks;
>
> 	qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
>@@ -1372,7 +1376,12 @@ 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 +1463,31 @@ 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 +1534,6 @@ 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 +1658,14 @@ 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 +1673,7 @@ 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

Regards,
 Sricharan