[PATCH RFC 3/8] pinctrl: qcom: Allow exposing reference clocks living in TLMM reg space

[Konrad Dybcio <konradybcio@kernel.org>]

From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Certain platforms (at least SM8750) had a number of registers
(responsible for gating refclk output to various consumers) moved to
TLMM. They're simple on/off toggles.

Expose them from the msm-pinctrl driver to allow for a reasonable DT
representation.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 92 ++++++++++++++++++++++++++++++++++++++
 drivers/pinctrl/qcom/pinctrl-msm.h | 14 ++++++
 2 files changed, 106 insertions(+)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index e99871b90ab9..1a52431a8605 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
  */
 
+#include <linux/clk-provider.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/gpio/driver.h>
@@ -16,6 +17,7 @@
 #include <linux/pm.h>
 #include <linux/firmware/qcom/qcom_scm.h>
 #include <linux/reboot.h>
+#include <linux/regmap.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -80,6 +82,7 @@ struct msm_pinctrl {
 	const struct msm_pinctrl_soc_data *soc;
 	void __iomem *regs[MAX_NR_TILES];
 	u32 phys_base[MAX_NR_TILES];
+	struct ref_clk ref_clks[];
 };
 
 #define MSM_ACCESSOR(name) \
@@ -1525,9 +1528,69 @@ SIMPLE_DEV_PM_OPS(msm_pinctrl_dev_pm_ops, msm_pinctrl_suspend,
 
 EXPORT_SYMBOL(msm_pinctrl_dev_pm_ops);
 
+static int clkref_enable(struct clk_hw *hw)
+{
+	struct ref_clk *rclk = container_of(hw, struct ref_clk, hw);
+	u32 val;
+
+	regmap_write(rclk->regmap, rclk->init.offset, BIT(0));
+	udelay(10);
+
+	regmap_read(rclk->regmap, rclk->init.offset, &val);
+
+	return (val & BIT(0)) ? 0 : -EINVAL;
+}
+
+static void clkref_disable(struct clk_hw *hw)
+{
+	struct ref_clk *rclk = container_of(hw, struct ref_clk, hw);
+
+	regmap_write(rclk->regmap, rclk->init.offset, 0);
+
+	udelay(10);
+}
+
+static int clkref_is_enabled(struct clk_hw *hw)
+{
+	struct ref_clk *rclk = container_of(hw, struct ref_clk, hw);
+	u32 val;
+
+	regmap_read(rclk->regmap, rclk->init.offset, &val);
+
+	return !!val;
+}
+
+static const struct clk_ops clkref_ops = {
+	.enable = clkref_enable,
+	.disable = clkref_disable,
+	.is_enabled = clkref_is_enabled,
+};
+
+static struct clk_hw *msm_pinctrl_clk_get(struct of_phandle_args *clkspec, void *data)
+{
+	struct msm_pinctrl *pctrl = data;
+	u32 idx = clkspec->args[0];
+
+	if (idx >= pctrl->soc->num_ref_clks)
+		return ERR_PTR(-EINVAL);
+
+	return &pctrl->ref_clks[idx].hw;
+}
+
+static const struct clk_parent_data clkref_parent_data = {
+	.index = 0, /* RPM(h) XO clock */
+};
+
+static const struct regmap_config clkref_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+};
+
 int msm_pinctrl_probe(struct platform_device *pdev,
 		      const struct msm_pinctrl_soc_data *soc_data)
 {
+	struct device *dev = &pdev->dev;
 	const struct pinfunction *func;
 	struct msm_pinctrl *pctrl;
 	struct resource *res;
@@ -1595,6 +1658,35 @@ int msm_pinctrl_probe(struct platform_device *pdev,
 	if (ret)
 		return ret;
 
+	if (soc_data->num_ref_clks) {
+		struct regmap *regmap = devm_regmap_init_mmio(dev, pctrl->regs[0],
+							      &clkref_regmap_config);
+		if (IS_ERR(regmap))
+			return PTR_ERR(regmap);
+
+		for (int i = 0; i < soc_data->num_ref_clks; i++) {
+			struct clk_hw *hw = &pctrl->ref_clks[i].hw;
+			struct clk_init_data init = { };
+
+			init.name = pctrl->soc->ref_clks[i]->name;
+			init.parent_data = &clkref_parent_data;
+			init.num_parents = 1;
+			init.ops = &clkref_ops;
+			hw->init = &init;
+
+			ret = devm_clk_hw_register(dev, hw);
+			if (ret)
+				return dev_err_probe(dev, ret, "Couldn't register clock %s\n",
+						     init.name);
+
+			pctrl->ref_clks[i].regmap = regmap;
+		}
+
+		ret = devm_of_clk_add_hw_provider(dev, msm_pinctrl_clk_get, pctrl);
+		if (ret)
+			return dev_err_probe(dev, ret, "Couldn't register clk provider\n");
+	}
+
 	platform_set_drvdata(pdev, pctrl);
 
 	dev_dbg(&pdev->dev, "Probed Qualcomm pinctrl driver\n");
diff --git a/drivers/pinctrl/qcom/pinctrl-msm.h b/drivers/pinctrl/qcom/pinctrl-msm.h
index 4625fa5320a9..213cc789711d 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.h
+++ b/drivers/pinctrl/qcom/pinctrl-msm.h
@@ -5,6 +5,7 @@
 #ifndef __PINCTRL_MSM_H__
 #define __PINCTRL_MSM_H__
 
+#include <linux/clk-provider.h>
 #include <linux/pm.h>
 #include <linux/types.h>
 
@@ -129,6 +130,17 @@ struct msm_gpio_wakeirq_map {
 	unsigned int wakeirq;
 };
 
+struct ref_clk_init_data {
+	const char * const name;
+	u32 offset;
+};
+
+struct ref_clk {
+	struct clk_hw hw;
+	struct regmap *regmap;
+	struct ref_clk_init_data init;
+};
+
 /**
  * struct msm_pinctrl_soc_data - Qualcomm pin controller driver configuration
  * @pins:	    An array describing all pins the pin controller affects.
@@ -170,6 +182,8 @@ struct msm_pinctrl_soc_data {
 	bool wakeirq_dual_edge_errata;
 	unsigned int gpio_func;
 	unsigned int egpio_func;
+	const struct ref_clk_init_data **ref_clks;
+	unsigned int num_ref_clks;
 };
 
 extern const struct dev_pm_ops msm_pinctrl_dev_pm_ops;

-- 
2.52.0