Re: [PATCH v4 07/27] clk: mediatek: clk-gate: Add ops for gates with HW voter

On Mon, Aug 25, 2025 at 2:52 PM Laura Nao [off-list ref] wrote:

On 8/15/25 05:37, Chen-Yu Tsai wrote:

quoted

On Tue, Aug 5, 2025 at 10:55 PM Laura Nao [off-list ref] wrote:

quoted

MT8196 use a HW voter for gate enable/disable control. Voting is
performed using set/clr regs, with a status bit used to verify the vote
state. Add new set of gate clock operations with support for voting via
set/clr regs.

Reviewed-by: Nícolas F. R. A. Prado <redacted>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Laura Nao <redacted>
---
 drivers/clk/mediatek/clk-gate.c | 77 +++++++++++++++++++++++++++++++--
 drivers/clk/mediatek/clk-gate.h |  3 ++
 2 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/mediatek/clk-gate.c b/drivers/clk/mediatek/clk-gate.c
index 0375ccad4be3..426f3a25763d 100644
--- a/drivers/clk/mediatek/clk-gate.c
+++ b/drivers/clk/mediatek/clk-gate.c

@@ -5,6 +5,7 @@
  */

 #include <linux/clk-provider.h>
+#include <linux/dev_printk.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/printk.h>

@@ -12,14 +13,19 @@
 #include <linux/slab.h>
 #include <linux/types.h>

+#include "clk-mtk.h"
 #include "clk-gate.h"

 struct mtk_clk_gate {
        struct clk_hw   hw;
        struct regmap   *regmap;
+       struct regmap   *regmap_hwv;
        int             set_ofs;
        int             clr_ofs;
        int             sta_ofs;
+       unsigned int    hwv_set_ofs;
+       unsigned int    hwv_clr_ofs;
+       unsigned int    hwv_sta_ofs;
        u8              bit;
 };

@@ -100,6 +106,28 @@ static void mtk_cg_disable_inv(struct clk_hw *hw)
        mtk_cg_clr_bit(hw);
 }

+static int mtk_cg_hwv_set_en(struct clk_hw *hw, bool enable)
+{
+       struct mtk_clk_gate *cg = to_mtk_clk_gate(hw);
+       u32 val;
+
+       regmap_write(cg->regmap_hwv, enable ? cg->hwv_set_ofs : cg->hwv_clr_ofs, BIT(cg->bit));
+
+       return regmap_read_poll_timeout_atomic(cg->regmap_hwv, cg->hwv_sta_ofs, val,
+                                              val & BIT(cg->bit),
+                                              0, MTK_WAIT_HWV_DONE_US);
+}
+
+static int mtk_cg_hwv_enable(struct clk_hw *hw)
+{
+       return mtk_cg_hwv_set_en(hw, true);
+}
+
+static void mtk_cg_hwv_disable(struct clk_hw *hw)
+{
+       mtk_cg_hwv_set_en(hw, false);
+}
+
 static int mtk_cg_enable_no_setclr(struct clk_hw *hw)
 {
        mtk_cg_clr_bit_no_setclr(hw);

@@ -124,6 +152,15 @@ static void mtk_cg_disable_inv_no_setclr(struct clk_hw *hw)
        mtk_cg_clr_bit_no_setclr(hw);
 }

+static bool mtk_cg_uses_hwv(const struct clk_ops *ops)
+{
+       if (ops == &mtk_clk_gate_hwv_ops_setclr ||
+           ops == &mtk_clk_gate_hwv_ops_setclr_inv)
+               return true;
+
+       return false;
+}
+
 const struct clk_ops mtk_clk_gate_ops_setclr = {
        .is_enabled     = mtk_cg_bit_is_cleared,
        .enable         = mtk_cg_enable,

@@ -138,6 +175,20 @@ const struct clk_ops mtk_clk_gate_ops_setclr_inv = {
 };
 EXPORT_SYMBOL_GPL(mtk_clk_gate_ops_setclr_inv);

+const struct clk_ops mtk_clk_gate_hwv_ops_setclr = {
+       .is_enabled     = mtk_cg_bit_is_cleared,
+       .enable         = mtk_cg_hwv_enable,
+       .disable        = mtk_cg_hwv_disable,
+};
+EXPORT_SYMBOL_GPL(mtk_clk_gate_hwv_ops_setclr);
+
+const struct clk_ops mtk_clk_gate_hwv_ops_setclr_inv = {
+       .is_enabled     = mtk_cg_bit_is_set,
+       .enable         = mtk_cg_hwv_enable,
+       .disable        = mtk_cg_hwv_disable,
+};
+EXPORT_SYMBOL_GPL(mtk_clk_gate_hwv_ops_setclr_inv);
+
 const struct clk_ops mtk_clk_gate_ops_no_setclr = {
        .is_enabled     = mtk_cg_bit_is_cleared,
        .enable         = mtk_cg_enable_no_setclr,

@@ -153,8 +204,9 @@ const struct clk_ops mtk_clk_gate_ops_no_setclr_inv = {
 EXPORT_SYMBOL_GPL(mtk_clk_gate_ops_no_setclr_inv);

 static struct clk_hw *mtk_clk_register_gate(struct device *dev,
-                                               const struct mtk_gate *gate,
-                                               struct regmap *regmap)
+                                           const struct mtk_gate *gate,
+                                           struct regmap *regmap,
+                                           struct regmap *regmap_hwv)
 {
        struct mtk_clk_gate *cg;
        int ret;

@@ -169,11 +221,22 @@ static struct clk_hw *mtk_clk_register_gate(struct device *dev,
        init.parent_names = gate->parent_name ? &gate->parent_name : NULL;
        init.num_parents = gate->parent_name ? 1 : 0;
        init.ops = gate->ops;
+       if (mtk_cg_uses_hwv(init.ops) && !regmap_hwv) {
+               dev_err(dev, "regmap not found for hardware voter clocks\n");
+               return ERR_PTR(-ENXIO);

return dev_err_probe()?

I believe the same applies to the previous patch.

mtk_clk_register_gate and mtk_clk_register_mux actually both return a
struct clk_hw *.

Oops, you're right. If that case I believe dev_err_ptr_probe() could be
used?

ChenYu