Merge tag 'reset-for-v5.11' of git://git.pengutronix.de/pza/linux into arm/drivers

Reset controller updates for v5.11

This tag adds support for sharing pulsed resets under certain
conditions. For example, when multiple drivers go through a
suspend-resume cycle, a reset line they share can be triggered
again during resume.
Further, the reset-meson driver now can be built as a module, the
reset-socfpga driver properly releases its memory region in the
probe error path, and reset-ti-syscon driver uses regmap_write_bits()
instead of regmap_update_bits() to support devices without status
readback.

* tag 'reset-for-v5.11' of git://git.pengutronix.de/pza/linux:
  reset-controller: ti: force the write operation when assert or deassert
  reset: socfpga: add error handling and release mem-region
  reset: meson: make it possible to build as a module
  reset: make shared pulsed reset controls re-triggerable

Link: https://lore.kernel.org/r/d586ada0073f2ac50a02274f42bf07bfb0603835.camel@pengutronix.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/reset/Kconfig

@@ -95,7 +95,8 @@ config RESET_LPC18XX
 	  This enables the reset controller driver for NXP LPC18xx/43xx SoCs.
 
 config RESET_MESON
-	bool "Meson Reset Driver" if COMPILE_TEST
+	tristate "Meson Reset Driver"
+	depends on ARCH_MESON || COMPILE_TEST
 	default ARCH_MESON
 	help
 	  This enables the reset driver for Amlogic Meson SoCs.

drivers/reset/core.c

@@ -208,6 +208,39 @@ static int reset_control_array_reset(struct reset_control_array *resets)
 	return 0;
 }
 
+static int reset_control_array_rearm(struct reset_control_array *resets)
+{
+	struct reset_control *rstc;
+	int i;
+
+	for (i = 0; i < resets->num_rstcs; i++) {
+		rstc = resets->rstc[i];
+
+		if (!rstc)
+			continue;
+
+		if (WARN_ON(IS_ERR(rstc)))
+			return -EINVAL;
+
+		if (rstc->shared) {
+			if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
+				return -EINVAL;
+		} else {
+			if (!rstc->acquired)
+				return -EPERM;
+		}
+	}
+
+	for (i = 0; i < resets->num_rstcs; i++) {
+		rstc = resets->rstc[i];
+
+		if (rstc && rstc->shared)
+			WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
+	}
+
+	return 0;
+}
+
 static int reset_control_array_assert(struct reset_control_array *resets)
 {
 	int ret, i;
@@ -325,6 +358,46 @@ int reset_control_reset(struct reset_control *rstc)
 }
 EXPORT_SYMBOL_GPL(reset_control_reset);
 
+/**
+ * reset_control_rearm - allow shared reset line to be re-triggered"
+ * @rstc: reset controller
+ *
+ * On a shared reset line the actual reset pulse is only triggered once for the
+ * lifetime of the reset_control instance, except if this call is used.
+ *
+ * Calls to this function must be balanced with calls to reset_control_reset,
+ * a warning is thrown in case triggered_count ever dips below 0.
+ *
+ * Consumers must not use reset_control_(de)assert on shared reset lines when
+ * reset_control_reset or reset_control_rearm have been used.
+ *
+ * If rstc is NULL the function will just return 0.
+ */
+int reset_control_rearm(struct reset_control *rstc)
+{
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
+		return -EINVAL;
+
+	if (reset_control_is_array(rstc))
+		return reset_control_array_rearm(rstc_to_array(rstc));
+
+	if (rstc->shared) {
+		if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
+			return -EINVAL;
+
+		WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
+	} else {
+		if (!rstc->acquired)
+			return -EPERM;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(reset_control_rearm);
+
 /**
  * reset_control_assert - asserts the reset line
  * @rstc: reset controller

drivers/reset/reset-meson.c

@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
@@ -104,6 +105,7 @@ static const struct of_device_id meson_reset_dt_ids[] = {
 	 { .compatible = "amlogic,meson-a1-reset",   .data = &meson_a1_param},
 	 { /* sentinel */ },
 };
+MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
 
 static int meson_reset_probe(struct platform_device *pdev)
 {
@@ -142,4 +144,8 @@ static struct platform_driver meson_reset_driver = {
 		.of_match_table	= meson_reset_dt_ids,
 	},
 };
-builtin_platform_driver(meson_reset_driver);
+module_platform_driver(meson_reset_driver);
+
+MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_LICENSE("Dual BSD/GPL");

drivers/reset/reset-socfpga.c

@@ -44,7 +44,7 @@ static int a10_reset_init(struct device_node *np)
 	data->membase = ioremap(res.start, size);
 	if (!data->membase) {
 		ret = -ENOMEM;
-		goto err_alloc;
+		goto release_region;
 	}
 
 	if (of_property_read_u32(np, "altr,modrst-offset", &reg_offset))
@@ -59,7 +59,14 @@ static int a10_reset_init(struct device_node *np)
 	data->rcdev.of_node = np;
 	data->status_active_low = true;
 
-	return reset_controller_register(&data->rcdev);
+	ret = reset_controller_register(&data->rcdev);
+	if (ret)
+		pr_err("unable to register device\n");
+
+	return ret;
+
+release_region:
+	release_mem_region(res.start, size);
 
 err_alloc:
 	kfree(data);

drivers/reset/reset-ti-syscon.c

@@ -89,7 +89,7 @@ static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,
 	mask = BIT(control->assert_bit);
 	value = (control->flags & ASSERT_SET) ? mask : 0x0;
 
-	return regmap_update_bits(data->regmap, control->assert_offset, mask, value);
+	return regmap_write_bits(data->regmap, control->assert_offset, mask, value);
 }
 
 /**
@@ -120,7 +120,7 @@ static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,
 	mask = BIT(control->deassert_bit);
 	value = (control->flags & DEASSERT_SET) ? mask : 0x0;
 
-	return regmap_update_bits(data->regmap, control->deassert_offset, mask, value);
+	return regmap_write_bits(data->regmap, control->deassert_offset, mask, value);
 }
 
 /**

include/linux/reset.h

@@ -13,6 +13,7 @@ struct reset_control;
 #ifdef CONFIG_RESET_CONTROLLER
 
 int reset_control_reset(struct reset_control *rstc);
+int reset_control_rearm(struct reset_control *rstc);
 int reset_control_assert(struct reset_control *rstc);
 int reset_control_deassert(struct reset_control *rstc);
 int reset_control_status(struct reset_control *rstc);