This patch implements save and restore context for peripheral fixed
clock ops, peripheral gate clock ops, sdmmc mux clock ops, and
peripheral clock ops.

During system suspend, core power goes off and looses the settings
of the Tegra CAR controller registers.

So during suspend entry clock and reset state of peripherals is saved
and on resume they are restored to have clocks back to same rate and
state as before suspend.

Acked-by: Thierry Reding <redacted>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
 drivers/clk/tegra/clk-periph-fixed.c | 31 ++++++++++++++++++++++++++
 drivers/clk/tegra/clk-periph-gate.c  | 34 ++++++++++++++++++++++++++++
 drivers/clk/tegra/clk-periph.c       | 43 ++++++++++++++++++++++++++++++++++++
 drivers/clk/tegra/clk-sdmmc-mux.c    | 30 +++++++++++++++++++++++++
 drivers/clk/tegra/clk.h              |  8 +++++++
 5 files changed, 146 insertions(+)

diff --git a/drivers/clk/tegra/clk-periph-fixed.c b/drivers/clk/tegra/clk-periph-fixed.c
index c088e7a280df..981f68b0a937 100644
--- a/drivers/clk/tegra/clk-periph-fixed.c
+++ b/drivers/clk/tegra/clk-periph-fixed.c

@@ -60,11 +60,42 @@ tegra_clk_periph_fixed_recalc_rate(struct clk_hw *hw,
 	return (unsigned long)rate;
 }
 
+static int tegra_clk_periph_fixed_save_context(struct clk_hw *hw)
+{
+	struct tegra_clk_periph_fixed *fixed = to_tegra_clk_periph_fixed(hw);
+	u32 mask = 1 << (fixed->num % 32);
+
+	fixed->enb_ctx = readl(fixed->base + fixed->regs->enb_reg) & mask;
+	fixed->rst_ctx = readl(fixed->base + fixed->regs->rst_reg) & mask;
+