Enable Second Level Clock Gating feature for supported chips.
With SLCG enabled, software need not control clocks anymore
and leave clocks enabled always on.

Signed-off-by: Shardar Shariff Md <smoham...@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewan...@nvidia.com>
Signed-off-by: Krishna Yarlagadda <kyarlaga...@nvidia.com>
---
 drivers/i2c/busses/i2c-tegra.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 2f654ed..8ab968e 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -235,6 +235,7 @@ struct tegra_i2c_hw_feature {
        u32 setup_hold_time_fast_fast_plus_mode;
        u32 setup_hold_time_hs_mode;
        bool has_interface_timing_reg;
+       bool has_slcg_support;
 };
 
 /**
@@ -299,6 +300,7 @@ struct tegra_i2c_dev {
        struct completion dma_complete;
        bool is_curr_atomic_xfer;
        int clk_divisor_hs_mode;
+       bool is_clkon_always;
 };
 
 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
@@ -1478,6 +1480,7 @@ static const struct tegra_i2c_hw_feature tegra20_i2c_hw = 
{
        .supports_bus_clear = false,
        .has_reg_write_buffering = true,
        .has_hs_mode_support = false,
+       .has_slcg_support = false,
        .has_apb_dma = true,
        .tlow_std_mode = 0x4,
        .thigh_std_mode = 0x2,
@@ -1506,6 +1509,7 @@ static const struct tegra_i2c_hw_feature tegra30_i2c_hw = 
{
        .supports_bus_clear = false,
        .has_reg_write_buffering = true,
        .has_hs_mode_support = false,
+       .has_slcg_support = false,
        .has_apb_dma = true,
        .tlow_std_mode = 0x4,
        .thigh_std_mode = 0x2,
@@ -1534,6 +1538,7 @@ static const struct tegra_i2c_hw_feature tegra114_i2c_hw 
= {
        .supports_bus_clear = true,
        .has_reg_write_buffering = true,
        .has_hs_mode_support = false,
+       .has_slcg_support = false,
        .has_apb_dma = true,
        .tlow_std_mode = 0x4,
        .thigh_std_mode = 0x2,
@@ -1562,6 +1567,7 @@ static const struct tegra_i2c_hw_feature tegra124_i2c_hw 
= {
        .supports_bus_clear = true,
        .has_reg_write_buffering = true,
        .has_hs_mode_support = false,
+       .has_slcg_support = false,
        .has_apb_dma = true,
        .tlow_std_mode = 0x4,
        .thigh_std_mode = 0x2,
@@ -1590,6 +1596,7 @@ static const struct tegra_i2c_hw_feature tegra210_i2c_hw 
= {
        .supports_bus_clear = true,
        .has_reg_write_buffering = true,
        .has_hs_mode_support = false,
+       .has_slcg_support = false,
        .has_apb_dma = true,
        .tlow_std_mode = 0x4,
        .thigh_std_mode = 0x2,
@@ -1618,6 +1625,7 @@ static const struct tegra_i2c_hw_feature tegra186_i2c_hw 
= {
        .supports_bus_clear = true,
        .has_reg_write_buffering = false,
        .has_hs_mode_support = false,
+       .has_slcg_support = true,
        .has_apb_dma = false,
        .tlow_std_mode = 0x4,
        .thigh_std_mode = 0x3,
@@ -1646,6 +1654,7 @@ static const struct tegra_i2c_hw_feature tegra194_i2c_hw 
= {
        .supports_bus_clear = true,
        .has_reg_write_buffering = false,
        .has_hs_mode_support = true,
+       .has_slcg_support = true,
        .has_apb_dma = false,
        .tlow_std_mode = 0x8,
        .thigh_std_mode = 0x7,
@@ -1822,7 +1831,12 @@ static int tegra_i2c_probe(struct platform_device *pdev)
                }
        }
 
-       if (i2c_dev->is_multimaster_mode) {
+       if (i2c_dev->is_multimaster_mode || i2c_dev->hw->has_slcg_support)
+               i2c_dev->is_clkon_always = true;
+       else
+               i2c_dev->is_clkon_always = false;
+
+       if (i2c_dev->is_clkon_always) {
                ret = clk_enable(i2c_dev->div_clk);
                if (ret < 0) {
                        dev_err(i2c_dev->dev, "div_clk enable failed %d\n",
@@ -1875,7 +1889,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
        tegra_i2c_release_dma(i2c_dev);
 
 disable_div_clk:
-       if (i2c_dev->is_multimaster_mode)
+       if (i2c_dev->is_clkon_always)
                clk_disable(i2c_dev->div_clk);
 
 put_rpm:
@@ -1908,7 +1922,7 @@ static int tegra_i2c_remove(struct platform_device *pdev)
 
        i2c_del_adapter(&i2c_dev->adapter);
 
-       if (i2c_dev->is_multimaster_mode)
+       if (i2c_dev->is_clkon_always)
                clk_disable(i2c_dev->div_clk);
 
        pm_runtime_disable(&pdev->dev);
@@ -1932,7 +1946,8 @@ static int __maybe_unused tegra_i2c_suspend(struct device 
*dev)
        struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
        int err = 0;
 
-       i2c_mark_adapter_suspended(&i2c_dev->adapter);
+       if (i2c_dev->is_clkon_always)
+               clk_disable(i2c_dev->div_clk);
 
        if (!pm_runtime_status_suspended(dev))
                err = tegra_i2c_runtime_suspend(dev);
@@ -1968,6 +1983,15 @@ static int __maybe_unused tegra_i2c_resume(struct device 
*dev)
                        return err;
        }
 
+       if (i2c_dev->is_clkon_always) {
+               err = clk_enable(i2c_dev->div_clk);
+               if (err < 0) {
+                       dev_err(i2c_dev->dev, "clock enable failed %d\n",
+                               err);
+                       return err;
+               }
+       }
+
        i2c_mark_adapter_resumed(&i2c_dev->adapter);
 
        return 0;
-- 
2.7.4

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