Re: [PATCH v8 06/12] clk: zte: Add regmap-based clocks

[Brian Masney]

On Mon, Jul 27, 2026 at 09:24:21PM +0300, Stefan Dösinger wrote:
> This is based on meson/clk-regmap.c, although slightly simplified. I
> have kept the copyright lines at the top of the file to indicate its
> origin.
> 
> I see that numerous clock drivers have their own incarnation of regmap-
> based mux/div/gate clocks. If there is any version of it that is likely
> to be elevated to shared code like clk-gate.c I'll copy that and try to
> use it as unmodified as possible.
> 
> Signed-off-by: Stefan Dösinger <stefandoesinger@xxxxxxxxx>
> 
> ---
> 
> Version 8: Use ZX297520V3_CLK_NO_EXPORT instead of 0 for unexported clocks.
> 
> Version 6: Remove stray regmap (Sashiko)
> 
> Version 5: Use regmap_test_bits in zte_clk_regmap_gate_is_enabled
> ---
>  drivers/clk/zte/clk-regmap.c | 218 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 215 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/zte/clk-regmap.c b/drivers/clk/zte/clk-regmap.c
> index 984abeb45ab2..671b81bcda4d 100644
> --- a/drivers/clk/zte/clk-regmap.c
> +++ b/drivers/clk/zte/clk-regmap.c
> @@ -7,28 +7,240 @@
>   */
>  
>  #include <linux/clk-provider.h>
> +#include <linux/container_of.h>
>  #include <linux/device.h>
>  #include <linux/regmap.h>
> +#include <linux/types.h>
>  #include <linux/errno.h>
> +#include <linux/bits.h>
> +#include <linux/err.h>
>  
>  #include "clk-zx.h"
>  
> +struct zte_clk_regmap {
> +	struct clk_hw	hw;
> +	struct regmap	*map;
> +	u16		reg;
> +	u8		shift;
> +	u8		size;
> +};
> +
> +static inline struct zte_clk_regmap *to_zte_clk_regmap(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct zte_clk_regmap, hw);
> +}
> +
> +static int zte_clk_regmap_gate_enable(struct clk_hw *hw)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +
> +	return regmap_set_bits(clk->map, clk->reg, BIT(clk->shift));
> +}
> +
> +static void zte_clk_regmap_gate_disable(struct clk_hw *hw)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +
> +	regmap_clear_bits(clk->map, clk->reg, BIT(clk->shift));
> +}
> +
> +static int zte_clk_regmap_gate_is_enabled(struct clk_hw *hw)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +
> +	return regmap_test_bits(clk->map, clk->reg, BIT(clk->shift));
> +}
> +
> +static const struct clk_ops zte_clk_regmap_gate_ops = {
> +	.enable		= zte_clk_regmap_gate_enable,
> +	.disable	= zte_clk_regmap_gate_disable,
> +	.is_enabled	= zte_clk_regmap_gate_is_enabled,
> +};
> +
>  int zx_clk_register_gates(struct device *dev, struct regmap *regmap,
>  			  const struct zx_gate_desc *desc, unsigned int num,
>  			  struct clk_hw_onecell_data *clocks)
>  {
> -	return -ENODEV;
> +	struct zte_clk_regmap *clk;
> +	unsigned int i;
> +	int res;
> +
> +	for (i = 0; i < num; ++i) {
> +		struct clk_init_data init = {};
> +
> +		clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
> +		if (!clk)
> +			return -ENOMEM;
> +
> +		init.name = desc[i].name;
> +		init.ops = &zte_clk_regmap_gate_ops;
> +		init.parent_names = &desc[i].parent;
> +		init.num_parents = 1;
> +		init.flags = CLK_SET_RATE_PARENT | desc[i].flags;
> +		clk->hw.init = &init;
> +		clk->map = regmap;
> +		clk->reg = desc[i].reg;
> +		clk->shift = desc[i].shift;
> +		clk->size = 1;
> +
> +		res = devm_clk_hw_register(dev, &clk->hw);
> +		if (res)
> +			return dev_err_probe(dev, res, "Failed to register clk %s\n", desc[i].name);
> +
> +		if (desc[i].id != ZX297520V3_CLK_NO_EXPORT)
> +			clocks->hws[desc[i].id] = &clk->hw;
> +	}
> +
> +	return 0;
> +}
> +
> +static unsigned long zte_clk_regmap_div_recalc_rate(struct clk_hw *hw,
> +						    unsigned long prate)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(clk->map, clk->reg, &val);
> +	if (ret)
> +		/* Gives a hint that something is wrong */
> +		return 0;
> +
> +	val >>= clk->shift;
> +	val &= clk_div_mask(clk->size);
> +	return divider_recalc_rate(hw, prate, val, NULL, 0, clk->size);

Newline before the return

> +}
> +
> +static int zte_clk_regmap_div_determine_rate(struct clk_hw *hw,
> +					     struct clk_rate_request *req)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +
> +	return divider_determine_rate(hw, req, NULL, clk->size, 0);
> +}
> +
> +static int zte_clk_regmap_div_set_rate(struct clk_hw *hw, unsigned long rate,
> +				       unsigned long parent_rate)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = divider_get_val(rate, parent_rate, NULL, clk->size, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	val = (unsigned int)ret << clk->shift;
> +	return regmap_update_bits(clk->map, clk->reg, clk_div_mask(clk->size) << clk->shift, val);
>  }
>  
> +static const struct clk_ops zte_clk_regmap_divider_ops = {
> +	.recalc_rate = zte_clk_regmap_div_recalc_rate,
> +	.determine_rate = zte_clk_regmap_div_determine_rate,
> +	.set_rate = zte_clk_regmap_div_set_rate,
> +};
> +
>  int zx_clk_register_dividers(struct device *dev, struct regmap *regmap,
>  			     const struct zx_div_desc *desc, unsigned int num)
>  {
> -	return -ENODEV;
> +	struct zte_clk_regmap *clk;
> +	unsigned int i;
> +	int res;
> +
> +	for (i = 0; i < num; ++i) {
> +		struct clk_init_data init = {};
> +
> +		clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
> +		if (!clk)
> +			return -ENOMEM;
> +
> +		init.name = desc[i].name;
> +		init.ops = &zte_clk_regmap_divider_ops;
> +		init.parent_names = &desc[i].parent;

Use parent_data instead of parent_names

> +		init.num_parents = 1;
> +		init.flags = CLK_SET_RATE_PARENT;
> +		clk->hw.init = &init;
> +		clk->map = regmap;
> +		clk->reg = desc[i].reg;
> +		clk->shift = desc[i].shift;
> +		clk->size = desc[i].size;
> +
> +		res = devm_clk_hw_register(dev, &clk->hw);
> +		if (res)
> +			return dev_err_probe(dev, res, "Failed to register clk %s\n", desc[i].name);
> +	}
> +
> +	return 0;
>  }
>  
> +static u8 zte_clk_regmap_mux_get_parent(struct clk_hw *hw)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(clk->map, clk->reg, &val);
> +	if (ret)
> +		return 0xff;
> +
> +	val >>= clk->shift;
> +	val &= GENMASK(clk->size - 1, 0);
> +	return clk_mux_val_to_index(hw, NULL, 0, val);
> +}
> +
> +static int zte_clk_regmap_mux_set_parent(struct clk_hw *hw, u8 index)
> +{
> +	struct zte_clk_regmap *clk = to_zte_clk_regmap(hw);
> +	unsigned int val = clk_mux_index_to_val(NULL, 0, index);
> +
> +	return regmap_update_bits(clk->map, clk->reg,
> +				  GENMASK(clk->size - 1, 0) << clk->shift,
> +				  val << clk->shift);
> +}
> +
> +static int zte_clk_regmap_mux_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
> +{
> +	return clk_mux_determine_rate_flags(hw, req, 0);
> +}
> +
> +static const struct clk_ops zte_clk_regmap_mux_ops = {
> +	.get_parent = zte_clk_regmap_mux_get_parent,
> +	.set_parent = zte_clk_regmap_mux_set_parent,
> +	.determine_rate = zte_clk_regmap_mux_determine_rate,
> +};
> +
>  int zx_clk_register_muxes(struct device *dev, struct regmap *regmap,
>  			  const struct zx_mux_desc *desc, unsigned int num,
>  			  struct clk_hw_onecell_data *clocks)
>  {
> -	return -ENODEV;
> +	struct zte_clk_regmap *clk;
> +	unsigned int i;
> +	int res;
> +
> +	for (i = 0; i < num; ++i) {
> +		struct clk_init_data init = {};
> +
> +		clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
> +		if (!clk)
> +			return -ENOMEM;
> +
> +		init.name = desc[i].name;
> +		init.ops = &zte_clk_regmap_mux_ops;
> +		init.parent_names = desc[i].parents;

Use parent_data instead of parent_names

Brian