diff options
Diffstat (limited to 'drivers/reset/reset-rzv2h-usb2phy.c')
| -rw-r--r-- | drivers/reset/reset-rzv2h-usb2phy.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/drivers/reset/reset-rzv2h-usb2phy.c b/drivers/reset/reset-rzv2h-usb2phy.c new file mode 100644 index 000000000000..ae643575b067 --- /dev/null +++ b/drivers/reset/reset-rzv2h-usb2phy.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Renesas RZ/V2H(P) USB2PHY Port reset control driver + * + * Copyright (C) 2025 Renesas Electronics Corporation + */ + +#include <linux/cleanup.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/reset.h> +#include <linux/reset-controller.h> + +struct rzv2h_usb2phy_regval { + u16 reg; + u16 val; +}; + +struct rzv2h_usb2phy_reset_of_data { + const struct rzv2h_usb2phy_regval *init_vals; + unsigned int init_val_count; + + u16 reset_reg; + u16 reset_assert_val; + u16 reset_deassert_val; + u16 reset_status_bits; + u16 reset_release_val; + + u16 reset2_reg; + u16 reset2_acquire_val; + u16 reset2_release_val; +}; + +struct rzv2h_usb2phy_reset_priv { + const struct rzv2h_usb2phy_reset_of_data *data; + void __iomem *base; + struct device *dev; + struct reset_controller_dev rcdev; + spinlock_t lock; /* protects register accesses */ +}; + +static inline struct rzv2h_usb2phy_reset_priv +*rzv2h_usbphy_rcdev_to_priv(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct rzv2h_usb2phy_reset_priv, rcdev); +} + +/* This function must be called only after pm_runtime_resume_and_get() has been called */ +static void rzv2h_usbphy_assert_helper(struct rzv2h_usb2phy_reset_priv *priv) +{ + const struct rzv2h_usb2phy_reset_of_data *data = priv->data; + + scoped_guard(spinlock, &priv->lock) { + writel(data->reset2_acquire_val, priv->base + data->reset2_reg); + writel(data->reset_assert_val, priv->base + data->reset_reg); + } + + usleep_range(11, 20); +} + +static int rzv2h_usbphy_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev); + struct device *dev = priv->dev; + int ret; + + ret = pm_runtime_resume_and_get(dev); + if (ret) { + dev_err(dev, "pm_runtime_resume_and_get failed\n"); + return ret; + } + + rzv2h_usbphy_assert_helper(priv); + + pm_runtime_put(dev); + + return 0; +} + +static int rzv2h_usbphy_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev); + const struct rzv2h_usb2phy_reset_of_data *data = priv->data; + struct device *dev = priv->dev; + int ret; + + ret = pm_runtime_resume_and_get(dev); + if (ret) { + dev_err(dev, "pm_runtime_resume_and_get failed\n"); + return ret; + } + + scoped_guard(spinlock, &priv->lock) { + writel(data->reset_deassert_val, priv->base + data->reset_reg); + writel(data->reset2_release_val, priv->base + data->reset2_reg); + writel(data->reset_release_val, priv->base + data->reset_reg); + } + + pm_runtime_put(dev); + + return 0; +} + +static int rzv2h_usbphy_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev); + struct device *dev = priv->dev; + int ret; + u32 reg; + + ret = pm_runtime_resume_and_get(dev); + if (ret) { + dev_err(dev, "pm_runtime_resume_and_get failed\n"); + return ret; + } + + reg = readl(priv->base + priv->data->reset_reg); + + pm_runtime_put(dev); + + return (reg & priv->data->reset_status_bits) == priv->data->reset_status_bits; +} + +static const struct reset_control_ops rzv2h_usbphy_reset_ops = { + .assert = rzv2h_usbphy_reset_assert, + .deassert = rzv2h_usbphy_reset_deassert, + .status = rzv2h_usbphy_reset_status, +}; + +static int rzv2h_usb2phy_reset_of_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) +{ + /* No special handling needed, we have only one reset line per device */ + return 0; +} + +static int rzv2h_usb2phy_reset_probe(struct platform_device *pdev) +{ + const struct rzv2h_usb2phy_reset_of_data *data; + struct rzv2h_usb2phy_reset_priv *priv; + struct device *dev = &pdev->dev; + struct reset_control *rstc; + int error; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + data = of_device_get_match_data(dev); + priv->data = data; + priv->dev = dev; + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + rstc = devm_reset_control_get_shared_deasserted(dev, NULL); + if (IS_ERR(rstc)) + return dev_err_probe(dev, PTR_ERR(rstc), + "failed to get deasserted reset\n"); + + spin_lock_init(&priv->lock); + + error = devm_pm_runtime_enable(dev); + if (error) + return dev_err_probe(dev, error, "Failed to enable pm_runtime\n"); + + error = pm_runtime_resume_and_get(dev); + if (error) + return dev_err_probe(dev, error, "pm_runtime_resume_and_get failed\n"); + + for (unsigned int i = 0; i < data->init_val_count; i++) + writel(data->init_vals[i].val, priv->base + data->init_vals[i].reg); + + /* keep usb2phy in asserted state */ + rzv2h_usbphy_assert_helper(priv); + + pm_runtime_put(dev); + + priv->rcdev.ops = &rzv2h_usbphy_reset_ops; + priv->rcdev.of_reset_n_cells = 0; + priv->rcdev.nr_resets = 1; + priv->rcdev.of_xlate = rzv2h_usb2phy_reset_of_xlate; + priv->rcdev.of_node = dev->of_node; + priv->rcdev.dev = dev; + + return devm_reset_controller_register(dev, &priv->rcdev); +} + +/* + * initialization values required to prepare the PHY to receive + * assert and deassert requests. + */ +static const struct rzv2h_usb2phy_regval rzv2h_init_vals[] = { + { .reg = 0xc10, .val = 0x67c }, + { .reg = 0xc14, .val = 0x1f }, + { .reg = 0x600, .val = 0x909 }, +}; + +static const struct rzv2h_usb2phy_reset_of_data rzv2h_reset_of_data = { + .init_vals = rzv2h_init_vals, + .init_val_count = ARRAY_SIZE(rzv2h_init_vals), + .reset_reg = 0, + .reset_assert_val = 0x206, + .reset_status_bits = BIT(2), + .reset_deassert_val = 0x200, + .reset_release_val = 0x0, + .reset2_reg = 0xb04, + .reset2_acquire_val = 0x303, + .reset2_release_val = 0x3, +}; + +static const struct of_device_id rzv2h_usb2phy_reset_of_match[] = { + { .compatible = "renesas,r9a09g057-usb2phy-reset", .data = &rzv2h_reset_of_data }, + { /* Sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rzv2h_usb2phy_reset_of_match); + +static struct platform_driver rzv2h_usb2phy_reset_driver = { + .driver = { + .name = "rzv2h_usb2phy_reset", + .of_match_table = rzv2h_usb2phy_reset_of_match, + }, + .probe = rzv2h_usb2phy_reset_probe, +}; +module_platform_driver(rzv2h_usb2phy_reset_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>"); +MODULE_DESCRIPTION("Renesas RZ/V2H(P) USB2PHY Control"); |