325 lines
8.9 KiB
C
325 lines
8.9 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only OR MIT
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/*
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* Apple SoC PMGR device power state driver
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*
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* Copyright The Asahi Linux Contributors
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*/
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#include <linux/bitops.h>
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#include <linux/bitfield.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/platform_device.h>
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#include <linux/pm_domain.h>
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#include <linux/regmap.h>
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#include <linux/mfd/syscon.h>
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#include <linux/reset-controller.h>
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#include <linux/module.h>
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#define APPLE_PMGR_RESET BIT(31)
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#define APPLE_PMGR_AUTO_ENABLE BIT(28)
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#define APPLE_PMGR_PS_AUTO GENMASK(27, 24)
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#define APPLE_PMGR_PS_MIN GENMASK(19, 16)
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#define APPLE_PMGR_PARENT_OFF BIT(11)
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#define APPLE_PMGR_DEV_DISABLE BIT(10)
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#define APPLE_PMGR_WAS_CLKGATED BIT(9)
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#define APPLE_PMGR_WAS_PWRGATED BIT(8)
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#define APPLE_PMGR_PS_ACTUAL GENMASK(7, 4)
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#define APPLE_PMGR_PS_TARGET GENMASK(3, 0)
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#define APPLE_PMGR_FLAGS (APPLE_PMGR_WAS_CLKGATED | APPLE_PMGR_WAS_PWRGATED)
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#define APPLE_PMGR_PS_ACTIVE 0xf
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#define APPLE_PMGR_PS_CLKGATE 0x4
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#define APPLE_PMGR_PS_PWRGATE 0x0
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#define APPLE_PMGR_PS_SET_TIMEOUT 100
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#define APPLE_PMGR_RESET_TIME 1
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struct apple_pmgr_ps {
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struct device *dev;
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struct generic_pm_domain genpd;
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struct reset_controller_dev rcdev;
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struct regmap *regmap;
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u32 offset;
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u32 min_state;
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};
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#define genpd_to_apple_pmgr_ps(_genpd) container_of(_genpd, struct apple_pmgr_ps, genpd)
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#define rcdev_to_apple_pmgr_ps(_rcdev) container_of(_rcdev, struct apple_pmgr_ps, rcdev)
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static int apple_pmgr_ps_set(struct generic_pm_domain *genpd, u32 pstate, bool auto_enable)
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{
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int ret;
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struct apple_pmgr_ps *ps = genpd_to_apple_pmgr_ps(genpd);
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u32 reg;
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ret = regmap_read(ps->regmap, ps->offset, ®);
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if (ret < 0)
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return ret;
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/* Resets are synchronous, and only work if the device is powered and clocked. */
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if (reg & APPLE_PMGR_RESET && pstate != APPLE_PMGR_PS_ACTIVE)
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dev_err(ps->dev, "PS %s: powering off with RESET active\n",
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genpd->name);
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reg &= ~(APPLE_PMGR_AUTO_ENABLE | APPLE_PMGR_FLAGS | APPLE_PMGR_PS_TARGET);
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reg |= FIELD_PREP(APPLE_PMGR_PS_TARGET, pstate);
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dev_dbg(ps->dev, "PS %s: pwrstate = 0x%x: 0x%x\n", genpd->name, pstate, reg);
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regmap_write(ps->regmap, ps->offset, reg);
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ret = regmap_read_poll_timeout_atomic(
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ps->regmap, ps->offset, reg,
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(FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == pstate), 1,
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APPLE_PMGR_PS_SET_TIMEOUT);
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if (ret < 0)
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dev_err(ps->dev, "PS %s: Failed to reach power state 0x%x (now: 0x%x)\n",
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genpd->name, pstate, reg);
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if (auto_enable) {
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/* Not all devices implement this; this is a no-op where not implemented. */
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reg &= ~APPLE_PMGR_FLAGS;
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reg |= APPLE_PMGR_AUTO_ENABLE;
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regmap_write(ps->regmap, ps->offset, reg);
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}
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return ret;
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}
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static bool apple_pmgr_ps_is_active(struct apple_pmgr_ps *ps)
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{
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u32 reg = 0;
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regmap_read(ps->regmap, ps->offset, ®);
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/*
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* We consider domains as active if they are actually on, or if they have auto-PM
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* enabled and the intended target is on.
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*/
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return (FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == APPLE_PMGR_PS_ACTIVE ||
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(FIELD_GET(APPLE_PMGR_PS_TARGET, reg) == APPLE_PMGR_PS_ACTIVE &&
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reg & APPLE_PMGR_AUTO_ENABLE));
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}
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static int apple_pmgr_ps_power_on(struct generic_pm_domain *genpd)
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{
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return apple_pmgr_ps_set(genpd, APPLE_PMGR_PS_ACTIVE, true);
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}
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static int apple_pmgr_ps_power_off(struct generic_pm_domain *genpd)
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{
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return apple_pmgr_ps_set(genpd, APPLE_PMGR_PS_PWRGATE, false);
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}
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static int apple_pmgr_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
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{
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struct apple_pmgr_ps *ps = rcdev_to_apple_pmgr_ps(rcdev);
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mutex_lock(&ps->genpd.mlock);
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if (ps->genpd.status == GENPD_STATE_OFF)
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dev_err(ps->dev, "PS 0x%x: asserting RESET while powered down\n", ps->offset);
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dev_dbg(ps->dev, "PS 0x%x: assert reset\n", ps->offset);
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/* Quiesce device before asserting reset */
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regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_DEV_DISABLE,
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APPLE_PMGR_DEV_DISABLE);
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regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_RESET,
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APPLE_PMGR_RESET);
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mutex_unlock(&ps->genpd.mlock);
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return 0;
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}
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static int apple_pmgr_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
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{
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struct apple_pmgr_ps *ps = rcdev_to_apple_pmgr_ps(rcdev);
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mutex_lock(&ps->genpd.mlock);
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dev_dbg(ps->dev, "PS 0x%x: deassert reset\n", ps->offset);
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regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_RESET, 0);
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regmap_update_bits(ps->regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_DEV_DISABLE, 0);
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if (ps->genpd.status == GENPD_STATE_OFF)
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dev_err(ps->dev, "PS 0x%x: RESET was deasserted while powered down\n", ps->offset);
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mutex_unlock(&ps->genpd.mlock);
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return 0;
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}
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static int apple_pmgr_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
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{
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int ret;
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ret = apple_pmgr_reset_assert(rcdev, id);
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if (ret)
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return ret;
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usleep_range(APPLE_PMGR_RESET_TIME, 2 * APPLE_PMGR_RESET_TIME);
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return apple_pmgr_reset_deassert(rcdev, id);
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}
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static int apple_pmgr_reset_status(struct reset_controller_dev *rcdev, unsigned long id)
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{
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struct apple_pmgr_ps *ps = rcdev_to_apple_pmgr_ps(rcdev);
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u32 reg = 0;
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regmap_read(ps->regmap, ps->offset, ®);
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return !!(reg & APPLE_PMGR_RESET);
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}
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const struct reset_control_ops apple_pmgr_reset_ops = {
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.assert = apple_pmgr_reset_assert,
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.deassert = apple_pmgr_reset_deassert,
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.reset = apple_pmgr_reset_reset,
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.status = apple_pmgr_reset_status,
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};
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static int apple_pmgr_reset_xlate(struct reset_controller_dev *rcdev,
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const struct of_phandle_args *reset_spec)
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{
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return 0;
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}
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static int apple_pmgr_ps_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *node = dev->of_node;
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struct apple_pmgr_ps *ps;
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struct regmap *regmap;
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struct of_phandle_iterator it;
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int ret;
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const char *name;
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bool active;
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regmap = syscon_node_to_regmap(node->parent);
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if (IS_ERR(regmap))
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return PTR_ERR(regmap);
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ps = devm_kzalloc(dev, sizeof(*ps), GFP_KERNEL);
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if (!ps)
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return -ENOMEM;
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ps->dev = dev;
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ps->regmap = regmap;
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ret = of_property_read_string(node, "label", &name);
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if (ret < 0) {
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dev_err(dev, "missing label property\n");
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return ret;
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}
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ret = of_property_read_u32(node, "reg", &ps->offset);
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if (ret < 0) {
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dev_err(dev, "missing reg property\n");
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return ret;
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}
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ps->genpd.name = name;
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ps->genpd.power_on = apple_pmgr_ps_power_on;
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ps->genpd.power_off = apple_pmgr_ps_power_off;
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ret = of_property_read_u32(node, "apple,min-state", &ps->min_state);
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if (ret == 0 && ps->min_state <= APPLE_PMGR_PS_ACTIVE)
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regmap_update_bits(regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_PS_MIN,
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FIELD_PREP(APPLE_PMGR_PS_MIN, ps->min_state));
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active = apple_pmgr_ps_is_active(ps);
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if (of_property_read_bool(node, "apple,always-on")) {
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ps->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
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if (!active) {
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dev_warn(dev, "always-on domain %s is not on at boot\n", name);
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/* Turn it on so pm_genpd_init does not fail */
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active = apple_pmgr_ps_power_on(&ps->genpd) == 0;
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}
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}
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/* Turn on auto-PM if the domain is already on */
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if (active)
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regmap_update_bits(regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_AUTO_ENABLE,
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APPLE_PMGR_AUTO_ENABLE);
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ret = pm_genpd_init(&ps->genpd, NULL, !active);
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if (ret < 0) {
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dev_err(dev, "pm_genpd_init failed\n");
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return ret;
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}
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ret = of_genpd_add_provider_simple(node, &ps->genpd);
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if (ret < 0) {
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dev_err(dev, "of_genpd_add_provider_simple failed\n");
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return ret;
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}
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of_for_each_phandle(&it, ret, node, "power-domains", "#power-domain-cells", -1) {
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struct of_phandle_args parent, child;
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parent.np = it.node;
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parent.args_count = of_phandle_iterator_args(&it, parent.args, MAX_PHANDLE_ARGS);
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child.np = node;
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child.args_count = 0;
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ret = of_genpd_add_subdomain(&parent, &child);
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if (ret == -EPROBE_DEFER) {
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of_node_put(parent.np);
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goto err_remove;
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} else if (ret < 0) {
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dev_err(dev, "failed to add to parent domain: %d (%s -> %s)\n",
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ret, it.node->name, node->name);
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of_node_put(parent.np);
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goto err_remove;
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}
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}
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/*
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* Do not participate in regular PM; parent power domains are handled via the
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* genpd hierarchy.
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*/
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pm_genpd_remove_device(dev);
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ps->rcdev.owner = THIS_MODULE;
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ps->rcdev.nr_resets = 1;
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ps->rcdev.ops = &apple_pmgr_reset_ops;
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ps->rcdev.of_node = dev->of_node;
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ps->rcdev.of_reset_n_cells = 0;
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ps->rcdev.of_xlate = apple_pmgr_reset_xlate;
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ret = devm_reset_controller_register(dev, &ps->rcdev);
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if (ret < 0)
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goto err_remove;
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return 0;
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err_remove:
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of_genpd_del_provider(node);
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pm_genpd_remove(&ps->genpd);
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return ret;
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}
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static const struct of_device_id apple_pmgr_ps_of_match[] = {
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{ .compatible = "apple,pmgr-pwrstate" },
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{}
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};
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MODULE_DEVICE_TABLE(of, apple_pmgr_ps_of_match);
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static struct platform_driver apple_pmgr_ps_driver = {
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.probe = apple_pmgr_ps_probe,
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.driver = {
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.name = "apple-pmgr-pwrstate",
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.of_match_table = apple_pmgr_ps_of_match,
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},
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};
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MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
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MODULE_DESCRIPTION("PMGR power state driver for Apple SoCs");
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MODULE_LICENSE("GPL v2");
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module_platform_driver(apple_pmgr_ps_driver);
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