clk: renesas: rzg2l: Add divider clock for RZ/G3S

Add a divider clock driver for RZ/G3S.  This will be used on RZ/G3S for
the SDHI, SPI, OCTA, I, I2, I3, P0, P1, P2, and P3 core clocks.
The divider has some limitation for SDHI, OCTA and SPI clocks:
  - SDHI div cannot be 1 if parent rate is 800MHz,
  - OCTA, SPI div cannot be 1 if parent rate is 400MHz.
To handle these limitations, a notifier is registered from platform
specific clock driver, which makes sure proper actions are taken before
the clock rate is changed, when needed.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20231006103959.197485-4-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 8f927568a3c8afee4f945e92c47a230e9d03b9f9..49dc6c5c0b0ca8a7f0f0ad7dd40a11dd74ab60ee 100644 (file)
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -93,6 +93,24 @@ struct sd_mux_hw_data {
 
 #define to_sd_mux_hw_data(_hw) container_of(_hw, struct sd_mux_hw_data, hw_data)
 
+/**
+ * struct div_hw_data - divider clock hardware data
+ * @hw_data: clock hw data
+ * @dtable: pointer to divider table
+ * @invalid_rate: invalid rate for divider
+ * @max_rate: maximum rate for divider
+ * @width: divider width
+ */
+struct div_hw_data {
+       struct clk_hw_data hw_data;
+       const struct clk_div_table *dtable;
+       unsigned long invalid_rate;
+       unsigned long max_rate;
+       u32 width;
+};
+
+#define to_div_hw_data(_hw)    container_of(_hw, struct div_hw_data, hw_data)
+
 struct rzg2l_pll5_param {
        u32 pl5_fracin;
        u8 pl5_refdiv;
@@ -201,6 +219,53 @@ int rzg2l_cpg_sd_clk_mux_notifier(struct notifier_block *nb, unsigned long event
        return notifier_from_errno(ret);
 }
 
+int rzg3s_cpg_div_clk_notifier(struct notifier_block *nb, unsigned long event,
+                              void *data)
+{
+       struct clk_notifier_data *cnd = data;
+       struct clk_hw *hw = __clk_get_hw(cnd->clk);
+       struct clk_hw_data *clk_hw_data = to_clk_hw_data(hw);
+       struct div_hw_data *div_hw_data = to_div_hw_data(clk_hw_data);
+       struct rzg2l_cpg_priv *priv = clk_hw_data->priv;
+       u32 off = GET_REG_OFFSET(clk_hw_data->conf);
+       u32 shift = GET_SHIFT(clk_hw_data->conf);
+       unsigned long flags;
+       int ret = 0;
+       u32 val;
+
+       if (event != PRE_RATE_CHANGE || !div_hw_data->invalid_rate ||
+           div_hw_data->invalid_rate % cnd->new_rate)
+               return NOTIFY_DONE;
+
+       spin_lock_irqsave(&priv->rmw_lock, flags);
+
+       val = readl(priv->base + off);
+       val >>= shift;
+       val &= GENMASK(GET_WIDTH(clk_hw_data->conf) - 1, 0);
+
+       /*
+        * There are different constraints for the user of this notifiers as follows:
+        * 1/ SD div cannot be 1 (val == 0) if parent rate is 800MHz
+        * 2/ OCTA / SPI div cannot be 1 (val == 0) if parent rate is 400MHz
+        * As SD can have only one parent having 800MHz and OCTA div can have
+        * only one parent having 400MHz we took into account the parent rate
+        * at the beginning of function (by checking invalid_rate % new_rate).
+        * Now it is time to check the hardware divider and update it accordingly.
+        */
+       if (!val) {
+               writel((CPG_WEN_BIT | 1) << shift, priv->base + off);
+               /* Wait for the update done. */
+               ret = rzg2l_cpg_wait_clk_update_done(priv->base, clk_hw_data->sconf);
+       }
+
+       spin_unlock_irqrestore(&priv->rmw_lock, flags);
+
+       if (ret)
+               dev_err(priv->dev, "Failed to downgrade the div\n");
+
+       return notifier_from_errno(ret);
+}
+
 static int rzg2l_register_notifier(struct clk_hw *hw, const struct cpg_core_clk *core,
                                   struct rzg2l_cpg_priv *priv)
 {
@@ -218,6 +283,124 @@ static int rzg2l_register_notifier(struct clk_hw *hw, const struct cpg_core_clk
        return clk_notifier_register(hw->clk, nb);
 }
 
+static unsigned long rzg3s_div_clk_recalc_rate(struct clk_hw *hw,
+                                              unsigned long parent_rate)
+{
+       struct clk_hw_data *clk_hw_data = to_clk_hw_data(hw);
+       struct div_hw_data *div_hw_data = to_div_hw_data(clk_hw_data);
+       struct rzg2l_cpg_priv *priv = clk_hw_data->priv;
+       u32 val;
+
+       val = readl(priv->base + GET_REG_OFFSET(clk_hw_data->conf));
+       val >>= GET_SHIFT(clk_hw_data->conf);
+       val &= GENMASK(GET_WIDTH(clk_hw_data->conf) - 1, 0);
+
+       return divider_recalc_rate(hw, parent_rate, val, div_hw_data->dtable,
+                                  CLK_DIVIDER_ROUND_CLOSEST, div_hw_data->width);
+}
+
+static int rzg3s_div_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+       struct clk_hw_data *clk_hw_data = to_clk_hw_data(hw);
+       struct div_hw_data *div_hw_data = to_div_hw_data(clk_hw_data);
+
+       if (div_hw_data->max_rate && req->rate > div_hw_data->max_rate)
+               req->rate = div_hw_data->max_rate;
+
+       return divider_determine_rate(hw, req, div_hw_data->dtable, div_hw_data->width,
+                                     CLK_DIVIDER_ROUND_CLOSEST);
+}
+
+static int rzg3s_div_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+                                 unsigned long parent_rate)
+{
+       struct clk_hw_data *clk_hw_data = to_clk_hw_data(hw);
+       struct div_hw_data *div_hw_data = to_div_hw_data(clk_hw_data);
+       struct rzg2l_cpg_priv *priv = clk_hw_data->priv;
+       u32 off = GET_REG_OFFSET(clk_hw_data->conf);
+       u32 shift = GET_SHIFT(clk_hw_data->conf);
+       unsigned long flags;
+       u32 val;
+       int ret;
+
+       val = divider_get_val(rate, parent_rate, div_hw_data->dtable, div_hw_data->width,
+                             CLK_DIVIDER_ROUND_CLOSEST);
+
+       spin_lock_irqsave(&priv->rmw_lock, flags);
+       writel((CPG_WEN_BIT | val) << shift, priv->base + off);
+       /* Wait for the update done. */
+       ret = rzg2l_cpg_wait_clk_update_done(priv->base, clk_hw_data->sconf);
+       spin_unlock_irqrestore(&priv->rmw_lock, flags);
+
+       return ret;
+}
+
+static const struct clk_ops rzg3s_div_clk_ops = {
+       .recalc_rate = rzg3s_div_clk_recalc_rate,
+       .determine_rate = rzg3s_div_clk_determine_rate,
+       .set_rate = rzg3s_div_clk_set_rate,
+};
+
+static struct clk * __init
+rzg3s_cpg_div_clk_register(const struct cpg_core_clk *core, struct clk **clks,
+                          void __iomem *base, struct rzg2l_cpg_priv *priv)
+{
+       struct div_hw_data *div_hw_data;
+       struct clk_init_data init = {};
+       const struct clk_div_table *clkt;
+       struct clk_hw *clk_hw;
+       const struct clk *parent;
+       const char *parent_name;
+       u32 max = 0;
+       int ret;
+
+       parent = clks[core->parent & 0xffff];
+       if (IS_ERR(parent))
+               return ERR_CAST(parent);
+
+       parent_name = __clk_get_name(parent);
+
+       div_hw_data = devm_kzalloc(priv->dev, sizeof(*div_hw_data), GFP_KERNEL);
+       if (!div_hw_data)
+               return ERR_PTR(-ENOMEM);
+
+       init.name = core->name;
+       init.flags = core->flag;
+       init.ops = &rzg3s_div_clk_ops;
+       init.parent_names = &parent_name;
+       init.num_parents = 1;
+
+       /* Get the maximum divider to retrieve div width. */
+       for (clkt = core->dtable; clkt->div; clkt++) {
+               if (max < clkt->div)
+                       max = clkt->div;
+       }
+
+       div_hw_data->hw_data.priv = priv;
+       div_hw_data->hw_data.conf = core->conf;
+       div_hw_data->hw_data.sconf = core->sconf;
+       div_hw_data->dtable = core->dtable;
+       div_hw_data->invalid_rate = core->invalid_rate;
+       div_hw_data->max_rate = core->max_rate;
+       div_hw_data->width = fls(max) - 1;
+
+       clk_hw = &div_hw_data->hw_data.hw;
+       clk_hw->init = &init;
+
+       ret = devm_clk_hw_register(priv->dev, clk_hw);
+       if (ret)
+               return ERR_PTR(ret);
+
+       ret = rzg2l_register_notifier(clk_hw, core, priv);
+       if (ret) {
+               dev_err(priv->dev, "Failed to register notifier for %s\n",
+                       core->name);
+               return ERR_PTR(ret);
+       }
+
+       return clk_hw->clk;
+}
+
 static struct clk * __init
 rzg2l_cpg_div_clk_register(const struct cpg_core_clk *core,
                           struct clk **clks,
@@ -963,6 +1146,9 @@ rzg2l_cpg_register_core_clk(const struct cpg_core_clk *core,
                clk = rzg2l_cpg_div_clk_register(core, priv->clks,
                                                 priv->base, priv);
                break;
+       case CLK_TYPE_G3S_DIV:
+               clk = rzg3s_cpg_div_clk_register(core, priv->clks, priv->base, priv);
+               break;
        case CLK_TYPE_MUX:
                clk = rzg2l_cpg_mux_clk_register(core, priv->base, priv);
                break;

diff --git a/drivers/clk/renesas/rzg2l-cpg.h b/drivers/clk/renesas/rzg2l-cpg.h
index f1910913b29a1ebbfba2e654a7ce8a5dc4ad5779..4755befaf38e5c0be8705804b5b77ddcc537ea38 100644 (file)
--- a/drivers/clk/renesas/rzg2l-cpg.h
+++ b/drivers/clk/renesas/rzg2l-cpg.h
@@ -89,6 +89,8 @@ struct cpg_core_clk {
        unsigned int sconf;
        const struct clk_div_table *dtable;
        const u32 *mtable;
+       const unsigned long invalid_rate;
+       const unsigned long max_rate;
        const char * const *parent_names;
        notifier_fn_t notifier;
        u32 flag;
@@ -105,6 +107,7 @@ enum clk_types {
 
        /* Clock with divider */
        CLK_TYPE_DIV,
+       CLK_TYPE_G3S_DIV,
 
        /* Clock with clock source selector */
        CLK_TYPE_MUX,
@@ -143,6 +146,13 @@ enum clk_types {
        DEF_TYPE(_name, _id, CLK_TYPE_DIV, .conf = _conf, \
                 .parent = _parent, .dtable = _dtable, \
                 .flag = CLK_DIVIDER_READ_ONLY)
+#define DEF_G3S_DIV(_name, _id, _parent, _conf, _sconf, _dtable, _invalid_rate, \
+                   _max_rate, _clk_flags, _notif) \
+       DEF_TYPE(_name, _id, CLK_TYPE_G3S_DIV, .conf = _conf, .sconf = _sconf, \
+                .parent = _parent, .dtable = _dtable, \
+                .invalid_rate = _invalid_rate, \
+                .max_rate = _max_rate, .flag = (_clk_flags), \
+                .notifier = _notif)
 #define DEF_MUX(_name, _id, _conf, _parent_names) \
        DEF_TYPE(_name, _id, CLK_TYPE_MUX, .conf = _conf, \
                 .parent_names = _parent_names, \
@@ -277,5 +287,6 @@ extern const struct rzg2l_cpg_info r9a07g054_cpg_info;
 extern const struct rzg2l_cpg_info r9a09g011_cpg_info;
 
 int rzg2l_cpg_sd_clk_mux_notifier(struct notifier_block *nb, unsigned long event, void *data);
+int rzg3s_cpg_div_clk_notifier(struct notifier_block *nb, unsigned long event, void *data);
 
 #endif