[PATCH 6.1.y-cip 07/85] clk: renesas: rzv2h: Add support for dynamic switching divider clocks

Tommaso Merciai
2025-03-13T01:32:55Z

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

commit bc4d25fdfadfa80dc3ba690792b5220d50ea7b52 upstream.

Add support for dynamic switching divider clocks.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20240828093822.162855-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
drivers/clk/renesas/rzv2h-cpg.c | 165 +++++++++++++++++++++++++++++++-
drivers/clk/renesas/rzv2h-cpg.h | 39 +++++++-
2 files changed, 201 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index 4e10cc835c63..9fa00f5c1237 100644
--- a/drivers/clk/renesas/rzv2h-cpg.c
+++ b/drivers/clk/renesas/rzv2h-cpg.c
@@ -45,14 +45,19 @@
#define PDIV(val) FIELD_GET(GENMASK(5, 0), (val))
#define SDIV(val) FIELD_GET(GENMASK(2, 0), (val))

+#define DDIV_DIVCTL_WEN(shift) BIT((shift) + 16)
+
#define GET_MOD_CLK_ID(base, index, bit) \
((base) + ((((index) * (16))) + (bit)))

+#define CPG_CLKSTATUS0 (0x700)
+
/**
* struct rzv2h_cpg_priv - Clock Pulse Generator Private Data
*
* @dev: CPG device
* @base: CPG register block base address
+ * @rmw_lock: protects register accesses
* @clks: Array containing all Core and Module Clocks
* @num_core_clks: Number of Core Clocks in clks[]
* @num_mod_clks: Number of Module Clocks in clks[]
@@ -64,6 +69,7 @@
struct rzv2h_cpg_priv {
struct device *dev;
void __iomem *base;
+ spinlock_t rmw_lock;

struct clk **clks;
unsigned int num_core_clks;
@@ -108,6 +114,21 @@ struct mod_clock {

#define to_mod_clock(_hw) container_of(_hw, struct mod_clock, hw)

+/**
+ * struct ddiv_clk - DDIV clock
+ *
+ * @priv: CPG private data
+ * @div: divider clk
+ * @mon: monitor bit in CPG_CLKSTATUS0 register
+ */
+struct ddiv_clk {
+ struct rzv2h_cpg_priv *priv;
+ struct clk_divider div;
+ u8 mon;
+};
+
+#define to_ddiv_clock(_div) container_of(_div, struct ddiv_clk, div)
+
static unsigned long rzv2h_cpg_pll_clk_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
@@ -161,7 +182,7 @@ rzv2h_cpg_pll_clk_register(const struct cpg_core_clk *core,
init.num_parents = 1;

pll_clk->hw.init = &init;
- pll_clk->conf = core->conf;
+ pll_clk->conf = core->cfg.conf;
pll_clk->base = base;
pll_clk->priv = priv;
pll_clk->type = core->type;
@@ -173,6 +194,143 @@ rzv2h_cpg_pll_clk_register(const struct cpg_core_clk *core,
return pll_clk->hw.clk;
}

+static unsigned long rzv2h_ddiv_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ unsigned int val;
+
+ val = readl(divider->reg) >> divider->shift;
+ val &= clk_div_mask(divider->width);
+
+ return divider_recalc_rate(hw, parent_rate, val, divider->table,
+ divider->flags, divider->width);
+}
+
+static long rzv2h_ddiv_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+
+ return divider_round_rate(hw, rate, prate, divider->table,
+ divider->width, divider->flags);
+}
+
+static int rzv2h_ddiv_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+
+ return divider_determine_rate(hw, req, divider->table, divider->width,
+ divider->flags);
+}
+
+static inline int rzv2h_cpg_wait_ddiv_clk_update_done(void __iomem *base, u8 mon)
+{
+ u32 bitmask = BIT(mon);
+ u32 val;
+
+ return readl_poll_timeout_atomic(base + CPG_CLKSTATUS0, val, !(val & bitmask), 10, 200);
+}
+
+static int rzv2h_ddiv_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ struct ddiv_clk *ddiv = to_ddiv_clock(divider);
+ struct rzv2h_cpg_priv *priv = ddiv->priv;
+ unsigned long flags = 0;
+ int value;
+ u32 val;
+ int ret;
+
+ value = divider_get_val(rate, parent_rate, divider->table,
+ divider->width, divider->flags);
+ if (value < 0)
+ return value;
+
+ spin_lock_irqsave(divider->lock, flags);
+
+ ret = rzv2h_cpg_wait_ddiv_clk_update_done(priv->base, ddiv->mon);
+ if (ret)
+ goto ddiv_timeout;
+
+ val = readl(divider->reg) | DDIV_DIVCTL_WEN(divider->shift);
+ val &= ~(clk_div_mask(divider->width) << divider->shift);
+ val |= (u32)value << divider->shift;
+ writel(val, divider->reg);
+
+ ret = rzv2h_cpg_wait_ddiv_clk_update_done(priv->base, ddiv->mon);
+ if (ret)
+ goto ddiv_timeout;
+
+ spin_unlock_irqrestore(divider->lock, flags);
+
+ return 0;
+
+ddiv_timeout:
+ spin_unlock_irqrestore(divider->lock, flags);
+ return ret;
+}
+
+static const struct clk_ops rzv2h_ddiv_clk_divider_ops = {
+ .recalc_rate = rzv2h_ddiv_recalc_rate,
+ .round_rate = rzv2h_ddiv_round_rate,
+ .determine_rate = rzv2h_ddiv_determine_rate,
+ .set_rate = rzv2h_ddiv_set_rate,
+};
+
+static struct clk * __init
+rzv2h_cpg_ddiv_clk_register(const struct cpg_core_clk *core,
+ struct rzv2h_cpg_priv *priv)
+{
+ struct ddiv cfg_ddiv = core->cfg.ddiv;
+ struct clk_init_data init = {};
+ struct device *dev = priv->dev;
+ u8 shift = cfg_ddiv.shift;
+ u8 width = cfg_ddiv.width;
+ const struct clk *parent;
+ const char *parent_name;
+ struct clk_divider *div;
+ struct ddiv_clk *ddiv;
+ int ret;
+
+ parent = priv->clks[core->parent];
+ if (IS_ERR(parent))
+ return ERR_CAST(parent);
+
+ parent_name = __clk_get_name(parent);
+
+ if ((shift + width) > 16)
+ return ERR_PTR(-EINVAL);
+
+ ddiv = devm_kzalloc(priv->dev, sizeof(*ddiv), GFP_KERNEL);
+ if (!ddiv)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = core->name;
+ init.ops = &rzv2h_ddiv_clk_divider_ops;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+
+ ddiv->priv = priv;
+ ddiv->mon = cfg_ddiv.monbit;
+ div = &ddiv->div;
+ div->reg = priv->base + cfg_ddiv.offset;
+ div->shift = shift;
+ div->width = width;
+ div->flags = core->flag;
+ div->lock = &priv->rmw_lock;
+ div->hw.init = &init;
+ div->table = core->dtable;
+
+ ret = devm_clk_hw_register(dev, &div->hw);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return div->hw.clk;
+}
+
static struct clk
*rzv2h_cpg_clk_src_twocell_get(struct of_phandle_args *clkspec,
void *data)
@@ -254,6 +412,9 @@ rzv2h_cpg_register_core_clk(const struct cpg_core_clk *core,
case CLK_TYPE_PLL:
clk = rzv2h_cpg_pll_clk_register(core, priv, &rzv2h_cpg_pll_ops);
break;
+ case CLK_TYPE_DDIV:
+ clk = rzv2h_cpg_ddiv_clk_register(core, priv);
+ break;
default:
goto fail;
}
@@ -612,6 +773,8 @@ static int __init rzv2h_cpg_probe(struct platform_device *pdev)
if (!priv)
return -ENOMEM;

+ spin_lock_init(&priv->rmw_lock);
+
priv->dev = dev;

priv->base = devm_platform_ioremap_resource(pdev, 0);
diff --git a/drivers/clk/renesas/rzv2h-cpg.h b/drivers/clk/renesas/rzv2h-cpg.h
index 6df59e041701..1c7a979ab790 100644
--- a/drivers/clk/renesas/rzv2h-cpg.h
+++ b/drivers/clk/renesas/rzv2h-cpg.h
@@ -8,6 +8,29 @@
#ifndef __RENESAS_RZV2H_CPG_H__
#define __RENESAS_RZV2H_CPG_H__

+/**
+ * struct ddiv - Structure for dynamic switching divider
+ *
+ * @offset: register offset
+ * @shift: position of the divider bit
+ * @width: width of the divider
+ * @monbit: monitor bit in CPG_CLKSTATUS0 register
+ */
+struct ddiv {
+ unsigned int offset:11;
+ unsigned int shift:4;
+ unsigned int width:4;
+ unsigned int monbit:5;
+};
+
+#define DDIV_PACK(_offset, _shift, _width, _monbit) \
+ ((struct ddiv){ \
+ .offset = _offset, \
+ .shift = _shift, \
+ .width = _width, \
+ .monbit = _monbit \
+ })
+
/**
* Definitions of CPG Core Clocks
*
@@ -23,7 +46,12 @@ struct cpg_core_clk {
unsigned int div;
unsigned int mult;
unsigned int type;
- unsigned int conf;
+ union {
+ unsigned int conf;
+ struct ddiv ddiv;
+ } cfg;
+ const struct clk_div_table *dtable;
+ u32 flag;
};

enum clk_types {
@@ -31,6 +59,7 @@ enum clk_types {
CLK_TYPE_IN, /* External Clock Input */
CLK_TYPE_FF, /* Fixed Factor Clock */
CLK_TYPE_PLL,
+ CLK_TYPE_DDIV, /* Dynamic Switching Divider */
};

/* BIT(31) indicates if CLK1/2 are accessible or not */
@@ -44,11 +73,17 @@ enum clk_types {
#define DEF_BASE(_name, _id, _type, _parent...) \
DEF_TYPE(_name, _id, _type, .parent = _parent)
#define DEF_PLL(_name, _id, _parent, _conf) \
- DEF_TYPE(_name, _id, CLK_TYPE_PLL, .parent = _parent, .conf = _conf)
+ DEF_TYPE(_name, _id, CLK_TYPE_PLL, .parent = _parent, .cfg.conf = _conf)
#define DEF_INPUT(_name, _id) \
DEF_TYPE(_name, _id, CLK_TYPE_IN)
#define DEF_FIXED(_name, _id, _parent, _mult, _div) \
DEF_BASE(_name, _id, CLK_TYPE_FF, _parent, .div = _div, .mult = _mult)
+#define DEF_DDIV(_name, _id, _parent, _ddiv_packed, _dtable) \
+ DEF_TYPE(_name, _id, CLK_TYPE_DDIV, \
+ .cfg.ddiv = _ddiv_packed, \
+ .parent = _parent, \
+ .dtable = _dtable, \
+ .flag = CLK_DIVIDER_HIWORD_MASK)

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