clk: ti: add support for register read-modify-write low-level operation

Useful for changing few bits on a register, this makes sure for example
that the operation is done atomically in case of syscon.

Signed-off-by: Tero Kristo <t-kristo@ti.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/drivers/clk/ti/clk.c b/drivers/clk/ti/clk.c
index f4d6802a8544..4efa2c9ea908 100644
--- a/drivers/clk/ti/clk.c
+++ b/drivers/clk/ti/clk.c
@@ -55,6 +55,29 @@ static void clk_memmap_writel(u32 val, const struct clk_omap_reg *reg)
                 writel_relaxed(val, io->mem + reg->offset);
 }
 
+static void _clk_rmw(u32 val, u32 mask, void __iomem *ptr)
+{
+        u32 v;
+
+        v = readl_relaxed(ptr);
+        v &= ~mask;
+        v |= val;
+        writel_relaxed(v, ptr);
+}
+
+static void clk_memmap_rmw(u32 val, u32 mask, const struct clk_omap_reg *reg)
+{
+        struct clk_iomap *io = clk_memmaps[reg->index];
+
+        if (reg->ptr) {
+                _clk_rmw(val, mask, reg->ptr);
+        } else if (io->regmap) {
+                regmap_update_bits(io->regmap, reg->offset, mask, val);
+        } else {
+                _clk_rmw(val, mask, io->mem + reg->offset);
+        }
+}
+
 static u32 clk_memmap_readl(const struct clk_omap_reg *reg)
 {
         u32 val;
@@ -89,6 +112,7 @@ int ti_clk_setup_ll_ops(struct ti_clk_ll_ops *ops)
         ti_clk_ll_ops = ops;
         ops->clk_readl = clk_memmap_readl;
         ops->clk_writel = clk_memmap_writel;
+        ops->clk_rmw = clk_memmap_rmw;
 
         return 0;
 }
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index d18da839b810..9e8611470187 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -211,6 +211,7 @@ enum {
  * struct ti_clk_ll_ops - low-level ops for clocks
  * @clk_readl: pointer to register read function
  * @clk_writel: pointer to register write function
+ * @clk_rmw: pointer to register read-modify-write function
  * @clkdm_clk_enable: pointer to clockdomain enable function
  * @clkdm_clk_disable: pointer to clockdomain disable function
  * @clkdm_lookup: pointer to clockdomain lookup function
@@ -226,6 +227,7 @@ enum {
 struct ti_clk_ll_ops {
         u32     (*clk_readl)(const struct clk_omap_reg *reg);
         void    (*clk_writel)(u32 val, const struct clk_omap_reg *reg);
+        void    (*clk_rmw)(u32 val, u32 mask, const struct clk_omap_reg *reg);
         int     (*clkdm_clk_enable)(struct clockdomain *clkdm, struct clk *clk);
         int     (*clkdm_clk_disable)(struct clockdomain *clkdm,
                                      struct clk *clk);