mfd: vexpress: Convert custom func API to regmap

Components of the Versatile Express platform (configuration
microcontrollers on motherboard and daughterboards in particular)
talk to each other over a custom configuration bus. They
provide miscellaneous functions (from clock generator control
to energy sensors) which are represented as platform devices
(and Device Tree nodes). The transactions on the bus can
be generated by different "bridges" in the system, some
of which are universal for the whole platform (for the price
of high transfer latencies), others restricted to a subsystem
(but much faster).

Until now drivers for such functions were using custom "func"
API, which is being replaced in this patch by regmap calls.
This required:

* a rework (and move to drivers/bus directory, as suggested
  by Samuel and Arnd) of the config bus core, which is much
  simpler now and uses device model infrastructure (class)
  to keep track of the bridges; non-DT case (soon to be
  retired anyway) is simply covered by a special device
  registration function

* the new config-bus driver also takes over device population,
  so there is no need for special matching table for
  of_platform_populate nor "simple-bus" hack in the arm64
  model dtsi file (relevant bindings documentation has
  been updated); this allows all the vexpress devices
  fit into normal device model, making it possible
  to remove plenty of early inits and other hacks in
  the near future

* adaptation of the syscfg bridge implementation in the
  sysreg driver, again making it much simpler; there is
  a special case of the "energy" function spanning two
  registers, where they should be both defined in the tree
  now, but backward compatibility is maintained in the code

* modification of the relevant drivers:

  * hwmon - just a straight-forward API change
  * power/reset driver - API change
  * regulator - API change plus error handling
    simplification
  * osc clock driver - this one required larger rework
    in order to turn in into a standard platform driver

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 42 insertions, 54 deletions

diff --git a/drivers/clk/versatile/clk-vexpress-osc.c b/drivers/clk/versatile/clk-vexpress-osc.c
index 422391242b3..529a59c0fbf 100644
--- a/drivers/clk/versatile/clk-vexpress-osc.c
+++ b/drivers/clk/versatile/clk-vexpress-osc.c
@@ -11,8 +11,6 @@
  * Copyright (C) 2012 ARM Limited
  */
 
-#define pr_fmt(fmt) "vexpress-osc: " fmt
-
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
 #include <linux/err.h>
@@ -22,7 +20,7 @@
 #include <linux/vexpress.h>
 
 struct vexpress_osc {
-	struct vexpress_config_func *func;
+	struct regmap *reg;
 	struct clk_hw hw;
 	unsigned long rate_min;
 	unsigned long rate_max;
@@ -36,7 +34,7 @@ static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
 	struct vexpress_osc *osc = to_vexpress_osc(hw);
 	u32 rate;
 
-	vexpress_config_read(osc->func, 0, &rate);
+	regmap_read(osc->reg, 0, &rate);
 
 	return rate;
 }
@@ -60,7 +58,7 @@ static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
 {
 	struct vexpress_osc *osc = to_vexpress_osc(hw);
 
-	return vexpress_config_write(osc->func, 0, rate);
+	return regmap_write(osc->reg, 0, rate);
 }
 
 static struct clk_ops vexpress_osc_ops = {
@@ -70,58 +68,31 @@ static struct clk_ops vexpress_osc_ops = {
 };
 
 
-struct clk * __init vexpress_osc_setup(struct device *dev)
-{
-	struct clk_init_data init;
-	struct vexpress_osc *osc = kzalloc(sizeof(*osc), GFP_KERNEL);
-
-	if (!osc)
-		return NULL;
-
-	osc->func = vexpress_config_func_get_by_dev(dev);
-	if (!osc->func) {
-		kfree(osc);
-		return NULL;
-	}
-
-	init.name = dev_name(dev);
-	init.ops = &vexpress_osc_ops;
-	init.flags = CLK_IS_ROOT;
-	init.num_parents = 0;
-	osc->hw.init = &init;
-
-	return clk_register(NULL, &osc->hw);
-}
-
-void __init vexpress_osc_of_setup(struct device_node *node)
+static int vexpress_osc_probe(struct platform_device *pdev)
 {
+	struct clk_lookup *cl = pdev->dev.platform_data; /* Non-DT lookup */
 	struct clk_init_data init;
 	struct vexpress_osc *osc;
 	struct clk *clk;
 	u32 range[2];
 
-	vexpress_sysreg_of_early_init();
-
-	osc = kzalloc(sizeof(*osc), GFP_KERNEL);
+	osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
 	if (!osc)
-		return;
+		return -ENOMEM;
 
-	osc->func = vexpress_config_func_get_by_node(node);
-	if (!osc->func) {
-		pr_err("Failed to obtain config func for node '%s'!\n",
-				node->full_name);
-		goto error;
-	}
+	osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
+	if (IS_ERR(osc->reg))
+		return PTR_ERR(osc->reg);
 
-	if (of_property_read_u32_array(node, "freq-range", range,
+	if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
 			ARRAY_SIZE(range)) == 0) {
 		osc->rate_min = range[0];
 		osc->rate_max = range[1];
 	}
 
-	of_property_read_string(node, "clock-output-names", &init.name);
-	if (!init.name)
-		init.name = node->full_name;
+	if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
+			&init.name) != 0)
+		init.name = dev_name(&pdev->dev);
 
 	init.ops = &vexpress_osc_ops;
 	init.flags = CLK_IS_ROOT;
@@ -130,20 +101,37 @@ void __init vexpress_osc_of_setup(struct device_node *node)
 	osc->hw.init = &init;
 
 	clk = clk_register(NULL, &osc->hw);
-	if (IS_ERR(clk)) {
-		pr_err("Failed to register clock '%s'!\n", init.name);
-		goto error;
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
+
+	/* Only happens for non-DT cases */
+	if (cl) {
+		cl->clk = clk;
+		clkdev_add(cl);
 	}
 
-	of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
+
+	return 0;
+}
 
-	pr_debug("Registered clock '%s'\n", init.name);
+static struct of_device_id vexpress_osc_of_match[] = {
+	{ .compatible = "arm,vexpress-osc", },
+	{}
+};
 
-	return;
+static struct platform_driver vexpress_osc_driver = {
+	.driver	= {
+		.name = "vexpress-osc",
+		.of_match_table = vexpress_osc_of_match,
+	},
+	.probe = vexpress_osc_probe,
+};
 
-error:
-	if (osc->func)
-		vexpress_config_func_put(osc->func);
-	kfree(osc);
+static int __init vexpress_osc_init(void)
+{
+	return platform_driver_register(&vexpress_osc_driver);
 }
-CLK_OF_DECLARE(vexpress_soc, "arm,vexpress-osc", vexpress_osc_of_setup);
+core_initcall(vexpress_osc_init);