[PATCH] i2c: tegra: Add ACPI support

[Akhil R <akhilrajeev@xxxxxxxxxx>]

Add support for ACPI based device registration so that the driver
can be also enabled through ACPI table.

Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx>
---
 drivers/i2c/busses/i2c-tegra.c | 52 +++++++++++++++++++++++++++++-------------
 1 file changed, 36 insertions(+), 16 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index c883044..781f747 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -6,6 +6,7 @@
  * Author: Colin Cross <ccross@xxxxxxxxxxx>
  */
 
+#include <linux/acpi.h>
 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
@@ -618,8 +619,13 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	 * emit a noisy warning on error, which won't stay unnoticed and
 	 * won't hose machine entirely.
 	 */
-	err = reset_control_reset(i2c_dev->rst);
-	WARN_ON_ONCE(err);
+	if (has_acpi_companion(i2c_dev->dev)) {
+		acpi_evaluate_object(ACPI_HANDLE(i2c_dev->dev), "_RST",
+				     NULL, NULL);
+	} else {
+		err = reset_control_reset(i2c_dev->rst);
+		WARN_ON_ONCE(err);
+	}
 
 	if (i2c_dev->is_dvc)
 		tegra_dvc_init(i2c_dev);
@@ -1627,12 +1633,12 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
 	bool multi_mode;
 	int err;
 
-	err = of_property_read_u32(np, "clock-frequency",
-				   &i2c_dev->bus_clk_rate);
+	err = device_property_read_u32(i2c_dev->dev, "clock-frequency",
+				       &i2c_dev->bus_clk_rate);
 	if (err)
 		i2c_dev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ;
 
-	multi_mode = of_property_read_bool(np, "multi-master");
+	multi_mode = device_property_read_bool(i2c_dev->dev, "multi-master");
 	i2c_dev->multimaster_mode = multi_mode;
 
 	if (of_device_is_compatible(np, "nvidia,tegra20-i2c-dvc"))
@@ -1684,6 +1690,9 @@ static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev)
 
 static void tegra_i2c_release_clocks(struct tegra_i2c_dev *i2c_dev)
 {
+	if (i2c_dev->nclocks == 0)
+		return;
+
 	if (i2c_dev->multimaster_mode)
 		clk_disable(i2c_dev->div_clk);
 
@@ -1720,7 +1729,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	init_completion(&i2c_dev->msg_complete);
 	init_completion(&i2c_dev->dma_complete);
 
-	i2c_dev->hw = of_device_get_match_data(&pdev->dev);
+	i2c_dev->hw = device_get_match_data(&pdev->dev);
 	i2c_dev->cont_id = pdev->id;
 	i2c_dev->dev = &pdev->dev;
 
@@ -1746,18 +1755,20 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
-	i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c");
-	if (IS_ERR(i2c_dev->rst)) {
-		dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst),
-			      "failed to get reset control\n");
-		return PTR_ERR(i2c_dev->rst);
-	}
-
 	tegra_i2c_parse_dt(i2c_dev);
 
-	err = tegra_i2c_init_clocks(i2c_dev);
-	if (err)
-		return err;
+	if (!has_acpi_companion(&pdev->dev)) {
+		i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c");
+		if (IS_ERR(i2c_dev->rst)) {
+			dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst),
+				      "failed to get reset control\n");
+			return PTR_ERR(i2c_dev->rst);
+		}
+
+		err = tegra_i2c_init_clocks(i2c_dev);
+		if (err)
+			return err;
+	}
 
 	err = tegra_i2c_init_dma(i2c_dev);
 	if (err)
@@ -1923,12 +1934,21 @@ static const struct dev_pm_ops tegra_i2c_pm = {
 			   NULL)
 };
 
+static const struct acpi_device_id tegra_i2c_acpi_match[] = {
+	{.id = "NVDA0101", .driver_data = (kernel_ulong_t)&tegra210_i2c_hw},
+	{.id = "NVDA0201", .driver_data = (kernel_ulong_t)&tegra186_i2c_hw},
+	{.id = "NVDA0301", .driver_data = (kernel_ulong_t)&tegra194_i2c_hw},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, tegra_i2c_acpi_match);
+
 static struct platform_driver tegra_i2c_driver = {
 	.probe = tegra_i2c_probe,
 	.remove = tegra_i2c_remove,
 	.driver = {
 		.name = "tegra-i2c",
 		.of_match_table = tegra_i2c_of_match,
+		.acpi_match_table = tegra_i2c_acpi_match,
 		.pm = &tegra_i2c_pm,
 	},
 };
-- 
2.7.4