[PATCH v3] i2c: tegra: Add the ACPI support

[Akhil R <akhilrajeev@nvidia.com>]

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

This does not include the ACPI support for Tegra VI and DVC I2C.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
 drivers/i2c/busses/i2c-tegra.c | 52 ++++++++++++++++++++++++++++++++----------
 1 file changed, 40 insertions(+), 12 deletions(-)

v3 changes
  * removed acpi_has_method check.
  * moved dev_err_probe to init_reset function to make it consistent with
	init_clocks.
  * Updates in commit message as suggested.

v2 - https://lkml.org/lkml/2021/11/23/82
v1 - https://lkml.org/lkml/2021/11/19/393

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index c883044..b889eb3 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -6,6 +6,7 @@
  * Author: Colin Cross <ccross@android.com>
  */
 
+#include <linux/acpi.h>
 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
@@ -608,6 +609,7 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 {
 	u32 val, clk_divisor, clk_multiplier, tsu_thd, tlow, thigh, non_hs_mode;
+	acpi_handle handle = ACPI_HANDLE(i2c_dev->dev);
 	int err;
 
 	/*
@@ -618,7 +620,11 @@ 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);
+	if (handle)
+		err = acpi_evaluate_object(handle, "_RST", NULL, NULL);
+	else
+		err = reset_control_reset(i2c_dev->rst);
+
 	WARN_ON_ONCE(err);
 
 	if (i2c_dev->is_dvc)
@@ -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"))
@@ -1642,10 +1648,26 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
 		i2c_dev->is_vi = true;
 }
 
+static int tegra_i2c_init_reset(struct tegra_i2c_dev *i2c_dev)
+{
+	if (has_acpi_companion(i2c_dev->dev))
+		return 0;
+
+	i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c");
+	if (IS_ERR(i2c_dev->rst))
+		return dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst),
+				      "failed to get reset control\n");
+
+	return 0;
+}
+
 static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev)
 {
 	int err;
 
+	if (has_acpi_companion(i2c_dev->dev))
+		return 0;
+
 	i2c_dev->clocks[i2c_dev->nclocks++].id = "div-clk";
 
 	if (i2c_dev->hw == &tegra20_i2c_hw || i2c_dev->hw == &tegra30_i2c_hw)
@@ -1720,7 +1742,7 @@ 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;
 
@@ -1746,15 +1768,12 @@ 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_reset(i2c_dev);
+	if (err)
+		return err;
+
 	err = tegra_i2c_init_clocks(i2c_dev);
 	if (err)
 		return err;
@@ -1923,12 +1942,21 @@ 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