[PATCH v6 01/21] clk: renesas: rzv2h: Add PLLDSI clk mux support

Tommaso Merciai
2026-04-08T10:37:57Z

Add PLLDSI clk mux support to select PLLDSI clock from different clock
sources.

Introduce the DEF_PLLDSI_SMUX() macro to define these muxes and register
them in the clock driver.

Extend the determine_rate callback to calculate and propagate PLL
parameters via rzv2h_get_pll_dtable_pars() when LVDS output is selected,
using a new helper function rzv2h_cpg_plldsi_smux_lvds_determine_rate().

The CLK_SMUX2_DSI{0,1}_CLK clock multiplexers select between two paths
with different duty cycles:

- CDIV7_DSIx_CLK (LVDS path, parent index 0): asymmetric H/L=4/3 duty (4/7)
- CSDIV_DSIx (DSI/RGB path, parent index 1): symmetric 50% duty (1/2)

Implement rzv2h_cpg_plldsi_smux_{get,set}_duty_cycle clock operations to
allow the DRM driver to query and configure the appropriate clock path
based on the required output duty cycle.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
v5->v6:
- Fixed rzv2h_cpg_plldsi_smux_clk_register() removed u8 width, mask
variables and replaced with direct use of smux.width and clk_div_mask(smux.width).

v4->v5:
- No chages.

v3->v4:
- Fixed build error using temporary variable mask
into rzv2h_cpg_plldsi_smux_clk_register().

v2->v3:
- Added missing defines for duty num/den

v1->v2:
- Added rzv2h_cpg_plldsi_smux_{get,set}_duty_cycle clock operations to
allow the DRM driver to query and configure the appropriate clock path
based on the required output duty cycle.
- Updated commit message accordingly.

drivers/clk/renesas/rzv2h-cpg.c | 181 ++++++++++++++++++++++++++++++++
drivers/clk/renesas/rzv2h-cpg.h | 8 ++
2 files changed, 189 insertions(+)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index f6c47fb89bca..e271c04cee34 100644
--- a/drivers/clk/renesas/rzv2h-cpg.c
+++ b/drivers/clk/renesas/rzv2h-cpg.c
@@ -76,6 +76,11 @@
/* On RZ/G3E SoC we have two DSI PLLs */
#define MAX_CPG_DSI_PLL 2

+#define CPG_PLLDSI_SMUX_LVDS_DUTY_NUM 4
+#define CPG_PLLDSI_SMUX_LVDS_DUTY_DEN 7
+#define CPG_PLLDSI_SMUX_DSI_RGB_DUTY_NUM 1
+#define CPG_PLLDSI_SMUX_DSI_RGB_DUTY_DEN 2
+
/**
* struct rzv2h_pll_dsi_info - PLL DSI information, holds the limits and parameters
*
@@ -418,6 +423,20 @@ bool rzv2h_get_pll_divs_pars(const struct rzv2h_pll_limits *limits,
}
EXPORT_SYMBOL_NS_GPL(rzv2h_get_pll_divs_pars, "RZV2H_CPG");

+/**
+ * struct rzv2h_plldsi_mux_clk - PLL DSI MUX clock
+ *
+ * @priv: CPG private data
+ * @mux: mux clk
+ */
+struct rzv2h_plldsi_mux_clk {
+ struct rzv2h_cpg_priv *priv;
+ struct clk_mux mux;
+};
+
+#define to_plldsi_clk_mux(_mux) \
+ container_of(_mux, struct rzv2h_plldsi_mux_clk, mux)
+
static unsigned long rzv2h_cpg_plldsi_div_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
@@ -649,6 +668,165 @@ static int rzv2h_cpg_plldsi_set_rate(struct clk_hw *hw, unsigned long rate,
return rzv2h_cpg_pll_set_rate(pll_clk, &dsi_info->pll_dsi_parameters.pll, true);
}

+static u8 rzv2h_cpg_plldsi_smux_get_parent(struct clk_hw *hw)
+{
+ return clk_mux_ops.get_parent(hw);
+}
+
+static int rzv2h_cpg_plldsi_smux_set_parent(struct clk_hw *hw, u8 index)
+{
+ return clk_mux_ops.set_parent(hw, index);
+}
+
+static int rzv2h_cpg_plldsi_smux_lvds_determine_rate(struct rzv2h_cpg_priv *priv,
+ struct pll_clk *pll_clk,
+ struct clk_rate_request *req)
+{
+ struct rzv2h_pll_div_pars *dsi_params;
+ struct rzv2h_pll_dsi_info *dsi_info;
+ u8 lvds_table[] = { 7 };
+ u64 rate_millihz;
+
+ dsi_info = &priv->pll_dsi_info[pll_clk->pll.instance];
+ dsi_params = &dsi_info->pll_dsi_parameters;
+
+ rate_millihz = mul_u32_u32(req->rate, MILLI);
+ if (!rzv2h_get_pll_divs_pars(dsi_info->pll_dsi_limits, dsi_params,
+ lvds_table, ARRAY_SIZE(lvds_table), rate_millihz)) {
+ dev_err(priv->dev, "failed to determine rate for req->rate: %lu\n",
+ req->rate);
+ return -EINVAL;
+ }
+
+ req->rate = DIV_ROUND_CLOSEST_ULL(dsi_params->div.freq_millihz, MILLI);
+ req->best_parent_rate = req->rate;
+ dsi_info->req_pll_dsi_rate = req->best_parent_rate * dsi_params->div.divider_value;
+
+ return 0;
+}
+
+static int rzv2h_cpg_plldsi_smux_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_mux *mux = to_clk_mux(hw);
+ struct rzv2h_plldsi_mux_clk *dsi_mux = to_plldsi_clk_mux(mux);
+ struct pll_clk *pll_clk = to_pll(clk_hw_get_parent(hw));
+ struct rzv2h_cpg_priv *priv = dsi_mux->priv;
+
+ /*
+ * For LVDS output (parent index 0), calculate PLL parameters with
+ * fixed divider value of 7. For DSI/RGB output (parent index 1) skip
+ * PLL calculation here as it's handled by determine_rate of the
+ * divider (up one level).
+ */
+ if (!clk_mux_ops.get_parent(hw))
+ return rzv2h_cpg_plldsi_smux_lvds_determine_rate(priv, pll_clk, req);
+
+ req->best_parent_rate = req->rate;
+ return 0;
+}
+
+static int rzv2h_cpg_plldsi_smux_get_duty_cycle(struct clk_hw *hw,
+ struct clk_duty *duty)
+{
+ u8 parent = clk_mux_ops.get_parent(hw);
+
+ /*
+ * CDIV7_DSIx_CLK - LVDS path (div7) - duty 4/7.
+ * CSDIV_DSIx - DSI/RGB path (csdiv) - duty 1/2.
+ */
+ if (parent == 0) {
+ duty->num = CPG_PLLDSI_SMUX_LVDS_DUTY_NUM;
+ duty->den = CPG_PLLDSI_SMUX_LVDS_DUTY_DEN;
+ } else {
+ duty->num = CPG_PLLDSI_SMUX_DSI_RGB_DUTY_NUM;
+ duty->den = CPG_PLLDSI_SMUX_DSI_RGB_DUTY_DEN;
+ }
+
+ return 0;
+}
+
+static int rzv2h_cpg_plldsi_smux_set_duty_cycle(struct clk_hw *hw,
+ struct clk_duty *duty)
+{
+ struct clk_hw *parent_hw;
+ u8 parent_idx;
+
+ /*
+ * Select parent based on requested duty cycle:
+ * - If duty > 50% (num/den > 1/2), select LVDS path (parent 0)
+ * - Otherwise, select DSI/RGB path (parent 1)
+ */
+ if (duty->num * CPG_PLLDSI_SMUX_DSI_RGB_DUTY_DEN >
+ duty->den * CPG_PLLDSI_SMUX_DSI_RGB_DUTY_NUM)
+ parent_idx = 0;
+ else
+ parent_idx = 1;
+
+ if (parent_idx >= clk_hw_get_num_parents(hw))
+ return -EINVAL;
+
+ parent_hw = clk_hw_get_parent_by_index(hw, parent_idx);
+ if (!parent_hw)
+ return -EINVAL;
+
+ return clk_hw_set_parent(hw, parent_hw);
+}
+
+static const struct clk_ops rzv2h_cpg_plldsi_smux_ops = {
+ .determine_rate = rzv2h_cpg_plldsi_smux_determine_rate,
+ .get_parent = rzv2h_cpg_plldsi_smux_get_parent,
+ .set_parent = rzv2h_cpg_plldsi_smux_set_parent,
+ .get_duty_cycle = rzv2h_cpg_plldsi_smux_get_duty_cycle,
+ .set_duty_cycle = rzv2h_cpg_plldsi_smux_set_duty_cycle,
+};
+
+static struct clk * __init
+rzv2h_cpg_plldsi_smux_clk_register(const struct cpg_core_clk *core,
+ struct rzv2h_cpg_priv *priv)
+{
+ struct rzv2h_plldsi_mux_clk *clk_hw_data;
+ struct clk_init_data init;
+ struct clk_hw *clk_hw;
+ struct smuxed smux;
+ int ret;
+
+ smux = core->cfg.smux;
+
+ if (smux.shift + smux.width > 16) {
+ dev_err(priv->dev, "mux value exceeds LOWORD field\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ clk_hw_data = devm_kzalloc(priv->dev, sizeof(*clk_hw_data), GFP_KERNEL);
+ if (!clk_hw_data)
+ return ERR_PTR(-ENOMEM);
+
+ clk_hw_data->priv = priv;
+
+ init.name = core->name;
+ init.ops = &rzv2h_cpg_plldsi_smux_ops;
+ init.flags = core->flag;
+ init.parent_names = core->parent_names;
+ init.num_parents = core->num_parents;
+
+ clk_hw_data->mux.reg = priv->base + smux.offset;
+
+ clk_hw_data->mux.shift = smux.shift;
+ clk_hw_data->mux.mask = clk_div_mask(smux.width);
+ clk_hw_data->mux.flags = core->mux_flags;
+ clk_hw_data->mux.lock = &priv->rmw_lock;
+
+ clk_hw = &clk_hw_data->mux.hw;
+ clk_hw->init = &init;
+
+ ret = devm_clk_hw_register(priv->dev, clk_hw);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return clk_hw->clk;
+}
+
static int rzv2h_cpg_pll_clk_is_enabled(struct clk_hw *hw)
{
struct pll_clk *pll_clk = to_pll(hw);
@@ -1085,6 +1263,9 @@ rzv2h_cpg_register_core_clk(const struct cpg_core_clk *core,
case CLK_TYPE_PLLDSI_DIV:
clk = rzv2h_cpg_plldsi_div_clk_register(core, priv);
break;
+ case CLK_TYPE_PLLDSI_SMUX:
+ clk = rzv2h_cpg_plldsi_smux_clk_register(core, priv);
+ break;
default:
goto fail;
}
diff --git a/drivers/clk/renesas/rzv2h-cpg.h b/drivers/clk/renesas/rzv2h-cpg.h
index dc957bdaf5e9..74a3824d605e 100644
--- a/drivers/clk/renesas/rzv2h-cpg.h
+++ b/drivers/clk/renesas/rzv2h-cpg.h
@@ -203,6 +203,7 @@ enum clk_types {
CLK_TYPE_SMUX, /* Static Mux */
CLK_TYPE_PLLDSI, /* PLLDSI */
CLK_TYPE_PLLDSI_DIV, /* PLLDSI divider */
+ CLK_TYPE_PLLDSI_SMUX, /* PLLDSI Static Mux */
};

#define DEF_TYPE(_name, _id, _type...) \
@@ -241,6 +242,13 @@ enum clk_types {
.dtable = _dtable, \
.parent = _parent, \
.flag = CLK_SET_RATE_PARENT)
+#define DEF_PLLDSI_SMUX(_name, _id, _smux_packed, _parent_names) \
+ DEF_TYPE(_name, _id, CLK_TYPE_PLLDSI_SMUX, \
+ .cfg.smux = _smux_packed, \
+ .parent_names = _parent_names, \
+ .num_parents = ARRAY_SIZE(_parent_names), \
+ .flag = CLK_SET_RATE_PARENT, \
+ .mux_flags = CLK_MUX_HIWORD_MASK)

/**
* struct rzv2h_mod_clk - Module Clocks definitions
--
2.43.0