Commit 6acab96e authored by Jai Luthra's avatar Jai Luthra Committed by Stephen Boyd
Browse files

clk: keystone: syscon-clk: Add support for audio refclk 

TI's AM62 SoC can optionally provide two audio reference clocks
(AUDIO_REFCLKx) to external peripherals.

By default this reference clock is looped-back inside the SoC to a mux
that goes to McASP AHCLK, but can optionally be enabled as an output to
peripherals outside the SoC by setting a bit through CTRL_MMR registers.

This bit only controls the direction of the clock, while the parent
is a muxed input from sci-clk [1] which may be a configurable PLL or a
master clock from one of the McASP instances.

Link: http://downloads.ti.com/tisci/esd/latest/5_soc_doc/am62x/clocks.html#clocks-for-board0-device

 [1]
Signed-off-by: default avatarJai Luthra <j-luthra@ti.com>
Link: https://lore.kernel.org/r/20230515-refclk-v3-2-37c0b550f406@ti.com


Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent daecb57c

drivers/clk/keystone/syscon-clk.c

+40 −5
Original line number Diff line number Diff line
@@ -4,10 +4,12 @@ 
 */



#include <linux/clk-provider.h>

#include <linux/kernel.h>

#include <linux/mfd/syscon.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/slab.h>



struct ti_syscon_gate_clk_priv {

	struct clk_hw hw;
@@ -61,21 +63,31 @@ static const struct clk_ops ti_syscon_gate_clk_ops = { 


static struct clk_hw

*ti_syscon_gate_clk_register(struct device *dev, struct regmap *regmap,

			     const char *parent_name,

			     const struct ti_syscon_gate_clk_data *data)

{

	struct ti_syscon_gate_clk_priv *priv;

	struct clk_init_data init;

	char *name = NULL;

	int ret;



	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return ERR_PTR(-ENOMEM);



	init.name = data->name;

	init.ops = &ti_syscon_gate_clk_ops;

	if (parent_name) {

		name = kasprintf(GFP_KERNEL, "%s:%s", data->name, parent_name);

		init.name = name;

		init.parent_names = &parent_name;

		init.num_parents = 1;

		init.flags = CLK_SET_RATE_PARENT;

	} else {

		init.name = data->name;

		init.parent_names = NULL;

		init.num_parents = 0;

		init.flags = 0;

	}



	priv->regmap = regmap;

	priv->reg = data->offset;
@@ -83,6 +95,10 @@ static struct clk_hw 
	priv->hw.init = &init;



	ret = devm_clk_hw_register(dev, &priv->hw);



	if (name)

		kfree(init.name);



	if (ret)

		return ERR_PTR(ret);
@@ -94,8 +110,9 @@ static int ti_syscon_gate_clk_probe(struct platform_device *pdev) 
	const struct ti_syscon_gate_clk_data *data, *p;

	struct clk_hw_onecell_data *hw_data;

	struct device *dev = &pdev->dev;

	int num_clks, num_parents, i;

	const char *parent_name;

	struct regmap *regmap;

	int num_clks, i;



	data = device_get_match_data(dev);

	if (!data)
@@ -110,6 +127,13 @@ static int ti_syscon_gate_clk_probe(struct platform_device *pdev) 
	for (p = data; p->name; p++)

		num_clks++;



	num_parents = of_clk_get_parent_count(dev->of_node);

	if (of_device_is_compatible(dev->of_node, "ti,am62-audio-refclk") &&

	    num_parents == 0) {

		return dev_err_probe(dev, -EINVAL,

				     "must specify a parent clock\n");

	}



	hw_data = devm_kzalloc(dev, struct_size(hw_data, hws, num_clks),

			       GFP_KERNEL);

	if (!hw_data)
@@ -117,8 +141,10 @@ static int ti_syscon_gate_clk_probe(struct platform_device *pdev) 


	hw_data->num = num_clks;



	parent_name = of_clk_get_parent_name(dev->of_node, 0);

	for (i = 0; i < num_clks; i++) {

		hw_data->hws[i] = ti_syscon_gate_clk_register(dev, regmap,

							      parent_name,

							      &data[i]);

		if (IS_ERR(hw_data->hws[i]))

			dev_warn(dev, "failed to register %s\n",
@@ -166,6 +192,11 @@ static const struct ti_syscon_gate_clk_data am62_clk_data[] = { 
	{ /* Sentinel */ },

};



static const struct ti_syscon_gate_clk_data am62_audio_clk_data[] = {

	TI_SYSCON_CLK_GATE("audio_refclk", 0x0, 15),

	{ /* Sentinel */ },

};



static const struct of_device_id ti_syscon_gate_clk_ids[] = {

	{

		.compatible = "ti,am654-ehrpwm-tbclk",
@@ -179,6 +210,10 @@ static const struct of_device_id ti_syscon_gate_clk_ids[] = { 
		.compatible = "ti,am62-epwm-tbclk",

		.data = &am62_clk_data,

	},

	{

		.compatible = "ti,am62-audio-refclk",

		.data = &am62_audio_clk_data,

	},

	{ }

};

MODULE_DEVICE_TABLE(of, ti_syscon_gate_clk_ids);