This patch adds a generic reset driver. It is designed to be useful when one has a register in a regmap which contains bits that reset other devices. I thought this seemed like a very generic use, so here is a generic driver. The overall structure has been modeled on the syscon-reboot driver.
Signed-off-by: Sean Anderson seanga2@gmail.com Reviewed-by: Simon Glass sjg@chromium.org ---
Changes in v5: - Reorder includes - Include linux/err.h explicitly
Changes in v4: - Added basic test - Fix incorrect usage of regmap_update_bits
Changes in v3: - New
arch/sandbox/dts/test.dts | 15 ++++ configs/sandbox_defconfig | 1 + .../reset/syscon-reset.txt | 36 +++++++++ drivers/reset/Kconfig | 5 ++ drivers/reset/Makefile | 1 + drivers/reset/reset-syscon.c | 80 +++++++++++++++++++ test/dm/Makefile | 1 + test/dm/syscon-reset.c | 58 ++++++++++++++ 8 files changed, 197 insertions(+) create mode 100644 doc/device-tree-bindings/reset/syscon-reset.txt create mode 100644 drivers/reset/reset-syscon.c create mode 100644 test/dm/syscon-reset.c
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts index 96e0b55eed..6f2fcc64a4 100644 --- a/arch/sandbox/dts/test.dts +++ b/arch/sandbox/dts/test.dts @@ -940,6 +940,21 @@ clocks = <&clk_sandbox 4>; power-domains = <&pwrdom 1>; }; + + resetc2: syscon-reset { + compatible = "syscon-reset"; + #reset-cells = <1>; + regmap = <&syscon0>; + offset = <1>; + mask = <0x27FFFFFF>; + assert-high = <0>; + }; + + syscon-reset-test { + compatible = "sandbox,misc_sandbox"; + resets = <&resetc2 15>, <&resetc2 30>, <&resetc2 60>; + reset-names = "valid", "no_mask", "out_of_range"; + }; };
#include "sandbox_pmic.dtsi" diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig index 22c1a073c4..ff0eaf3c4d 100644 --- a/configs/sandbox_defconfig +++ b/configs/sandbox_defconfig @@ -191,6 +191,7 @@ CONFIG_DM_RESET=y CONFIG_SANDBOX_RESET=y CONFIG_DM_RNG=y CONFIG_RNG_SANDBOX=y +CONFIG_RESET_SYSCON=y CONFIG_DM_RTC=y CONFIG_RTC_RV8803=y CONFIG_DEBUG_UART_SANDBOX=y diff --git a/doc/device-tree-bindings/reset/syscon-reset.txt b/doc/device-tree-bindings/reset/syscon-reset.txt new file mode 100644 index 0000000000..f136b3d225 --- /dev/null +++ b/doc/device-tree-bindings/reset/syscon-reset.txt @@ -0,0 +1,36 @@ +Generic SYSCON mapped register reset driver + +This is a generic reset driver using syscon to map the reset register. +The reset is generally performed with a write to the reset register +defined by the register map pointed by syscon reference plus the offset and +shifted by the reset specifier/ + +To assert a reset on some device, the equivalent of the following operation is +performed, where reset_id is the reset specifier from the device's resets +property. + + if (BIT(reset_id) & mask) + regmap[offset][reset_id] = assert-high; + +Required properties: +- compatible: should contain "syscon-reset" +- #reset-cells: must be 1 +- regmap: this is phandle to the register map node +- offset: offset in the register map for the reboot register (in bytes) + +Optional properties: +- mask: accept only the reset specifiers defined by the mask (32 bit) +- assert-high: Bit to write when asserting a reset. Defaults to 1. + +Default will be little endian mode, 32 bit access only. + +Example: + + reset-controller { + compatible = "syscon-reset"; + #reset-cells = <1>; + regmap = <&sysctl>; + offset = <0x20>; + mask = <0x27FFFFFF>; + assert-high = <0>; + }; diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index 75ccd65799..097bf32b21 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -148,4 +148,9 @@ config RESET_IMX7 help Support for reset controller on i.MX7/8 SoCs.
+config RESET_SYSCON + bool "Enable generic syscon reset driver support" + depends on DM_RESET + help + Support generic syscon mapped register reset devices. endmenu diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index 0a044d5d8c..433f1eca54 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -23,3 +23,4 @@ obj-$(CONFIG_RESET_MTMIPS) += reset-mtmips.o obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o obj-$(CONFIG_RESET_HISILICON) += reset-hisilicon.o obj-$(CONFIG_RESET_IMX7) += reset-imx7.o +obj-$(CONFIG_RESET_SYSCON) += reset-syscon.o diff --git a/drivers/reset/reset-syscon.c b/drivers/reset/reset-syscon.c new file mode 100644 index 0000000000..34dfe0bab6 --- /dev/null +++ b/drivers/reset/reset-syscon.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020 Sean Anderson + */ + +#include <common.h> +#include <dm.h> +#include <regmap.h> +#include <reset.h> +#include <reset-uclass.h> +#include <syscon.h> +#include <linux/err.h> + +struct syscon_reset_priv { + struct regmap *regmap; + uint offset; + uint mask; + bool assert_high; +}; + +static int syscon_reset_request(struct reset_ctl *rst) +{ + struct syscon_reset_priv *priv = dev_get_priv(rst->dev); + + if (BIT(rst->id) & priv->mask) + return 0; + else + return -EINVAL; +} + +static int syscon_reset_assert(struct reset_ctl *rst) +{ + struct syscon_reset_priv *priv = dev_get_priv(rst->dev); + + return regmap_update_bits(priv->regmap, priv->offset, BIT(rst->id), + priv->assert_high ? BIT(rst->id) : 0); +} + +static int syscon_reset_deassert(struct reset_ctl *rst) +{ + struct syscon_reset_priv *priv = dev_get_priv(rst->dev); + + return regmap_update_bits(priv->regmap, priv->offset, BIT(rst->id), + priv->assert_high ? 0 : BIT(rst->id)); +} + +static const struct reset_ops syscon_reset_ops = { + .request = syscon_reset_request, + .rst_assert = syscon_reset_assert, + .rst_deassert = syscon_reset_deassert, +}; + +int syscon_reset_probe(struct udevice *dev) +{ + struct syscon_reset_priv *priv = dev_get_priv(dev); + + priv->regmap = syscon_regmap_lookup_by_phandle(dev, "regmap"); + if (IS_ERR(priv->regmap)) + return -ENODEV; + + priv->offset = dev_read_u32_default(dev, "offset", 0); + priv->mask = dev_read_u32_default(dev, "mask", 0); + priv->assert_high = dev_read_u32_default(dev, "assert-high", true); + + return 0; +} + +static const struct udevice_id syscon_reset_ids[] = { + { .compatible = "syscon-reset" }, + { }, +}; + +U_BOOT_DRIVER(syscon_reset) = { + .name = "syscon_reset", + .id = UCLASS_RESET, + .of_match = syscon_reset_ids, + .probe = syscon_reset_probe, + .priv_auto_alloc_size = sizeof(struct syscon_reset_priv), + .ops = &syscon_reset_ops, +}; diff --git a/test/dm/Makefile b/test/dm/Makefile index e0be0d684f..187f288362 100644 --- a/test/dm/Makefile +++ b/test/dm/Makefile @@ -72,4 +72,5 @@ obj-$(CONFIG_DM_MDIO_MUX) += mdio_mux.o obj-$(CONFIG_DM_RNG) += rng.o obj-$(CONFIG_CLK_K210_SET_RATE) += k210_pll.o obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o +obj-$(CONFIG_RESET_SYSCON) += syscon-reset.o endif diff --git a/test/dm/syscon-reset.c b/test/dm/syscon-reset.c new file mode 100644 index 0000000000..1db0206e00 --- /dev/null +++ b/test/dm/syscon-reset.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2020 Sean Anderson seanga2@gmail.com + */ + +#include <common.h> +#include <dm.h> +#include <dm/test.h> +#include <regmap.h> +#include <reset.h> +#include <syscon.h> +#include <test/ut.h> +#include <asm/test.h> + +/* The following values must match the device tree */ +#define TEST_RESET_REG 1 +#define TEST_RESET_ASSERT_HIGH 0 +#define TEST_RESET_ASSERT (TEST_RESET_ASSERT_HIGH ? (u32)-1 : (u32)0) +#define TEST_RESET_DEASSERT (~TEST_RESET_ASSERT) + +#define TEST_RESET_VALID 15 +#define TEST_RESET_NOMASK 30 +#define TEST_RESET_OUTOFRANGE 60 + +static int dm_test_syscon_reset(struct unit_test_state *uts) +{ + struct regmap *map; + struct reset_ctl rst; + struct udevice *reset; + struct udevice *syscon; + struct udevice *syscon_reset; + uint reg; + + ut_assertok(uclass_get_device_by_name(UCLASS_MISC, "syscon-reset-test", + &reset)); + ut_assertok(uclass_get_device_by_name(UCLASS_SYSCON, "syscon@0", + &syscon)); + ut_assertok(uclass_get_device_by_name(UCLASS_RESET, "syscon-reset", + &syscon_reset)); + ut_assertok_ptr((map = syscon_get_regmap(syscon))); + + ut_asserteq(-EINVAL, reset_get_by_name(reset, "no_mask", &rst)); + ut_asserteq(-EINVAL, reset_get_by_name(reset, "out_of_range", &rst)); + ut_assertok(reset_get_by_name(reset, "valid", &rst)); + + sandbox_set_enable_memio(true); + ut_assertok(regmap_write(map, TEST_RESET_REG, TEST_RESET_DEASSERT)); + ut_assertok(reset_assert(&rst)); + ut_assertok(regmap_read(map, TEST_RESET_REG, ®)); + ut_asserteq(TEST_RESET_DEASSERT ^ BIT(TEST_RESET_VALID), reg); + + ut_assertok(reset_deassert(&rst)); + ut_assertok(regmap_read(map, TEST_RESET_REG, ®)); + ut_asserteq(TEST_RESET_DEASSERT, reg); + + return 0; +} +DM_TEST(dm_test_syscon_reset, DM_TESTF_SCAN_FDT);