[v4,03/13] clk: microchip: mpfs: add reset controller

Add a reset controller to PolarFire SoC's clock driver. This reset
controller is registered as an aux device and read/write functions
exported to the drivers namespace so that the reset controller can
access the peripheral device reset register.

Reviewed-by: Daire McNamara <daire.mcnamara@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/clk/microchip/Kconfig    |   1 +
 drivers/clk/microchip/clk-mpfs.c | 110 +++++++++++++++++++++++++++----
 include/soc/microchip/mpfs.h     |   8 +++
 3 files changed, 107 insertions(+), 12 deletions(-)

On 30.08.2022 15:52, Conor Dooley wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Add a reset controller to PolarFire SoC's clock driver. This reset
> controller is registered as an aux device and read/write functions
> exported to the drivers namespace so that the reset controller can
> access the peripheral device reset register.
> 
> Reviewed-by: Daire McNamara <daire.mcnamara@microchip.com>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>


> ---
>  drivers/clk/microchip/Kconfig    |   1 +
>  drivers/clk/microchip/clk-mpfs.c | 110 +++++++++++++++++++++++++++----
>  include/soc/microchip/mpfs.h     |   8 +++
>  3 files changed, 107 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/clk/microchip/Kconfig b/drivers/clk/microchip/Kconfig
> index a5a99873c4f5..b46e864b3bd8 100644
> --- a/drivers/clk/microchip/Kconfig
> +++ b/drivers/clk/microchip/Kconfig
> @@ -6,5 +6,6 @@ config COMMON_CLK_PIC32
>  config MCHP_CLK_MPFS
>         bool "Clk driver for PolarFire SoC"
>         depends on (RISCV && SOC_MICROCHIP_POLARFIRE) || COMPILE_TEST
> +       select AUXILIARY_BUS
>         help
>           Supports Clock Configuration for PolarFire SoC
> diff --git a/drivers/clk/microchip/clk-mpfs.c b/drivers/clk/microchip/clk-mpfs.c
> index 9e41f07b3fa6..43cc9583cd14 100644
> --- a/drivers/clk/microchip/clk-mpfs.c
> +++ b/drivers/clk/microchip/clk-mpfs.c
> @@ -3,12 +3,14 @@
>   * Daire McNamara,<daire.mcnamara@microchip.com>
>   * Copyright (C) 2020 Microchip Technology Inc.  All rights reserved.
>   */
> +#include <linux/auxiliary_bus.h>
>  #include <linux/clk-provider.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <dt-bindings/clock/microchip,mpfs-clock.h>
> +#include <soc/microchip/mpfs.h>
> 
>  /* address offset of control registers */
>  #define REG_MSSPLL_REF_CR      0x08u
> @@ -30,6 +32,7 @@
>  #define RTCREF_OFFSET          (CLK_RTCREF - CLK_ENVM)
> 
>  struct mpfs_clock_data {
> +       struct device *dev;
>         void __iomem *base;
>         void __iomem *msspll_base;
>         struct clk_hw_onecell_data hw_data;
> @@ -304,10 +307,6 @@ static int mpfs_periph_clk_enable(struct clk_hw *hw)
> 
>         spin_lock_irqsave(&mpfs_clk_lock, flags);
> 
> -       reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
> -       val = reg & ~(1u << periph->shift);
> -       writel_relaxed(val, base_addr + REG_SUBBLK_RESET_CR);
> -
>         reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
>         val = reg | (1u << periph->shift);
>         writel_relaxed(val, base_addr + REG_SUBBLK_CLOCK_CR);
> @@ -341,12 +340,9 @@ static int mpfs_periph_clk_is_enabled(struct clk_hw *hw)
>         void __iomem *base_addr = periph_hw->sys_base;
>         u32 reg;
> 
> -       reg = readl_relaxed(base_addr + REG_SUBBLK_RESET_CR);
> -       if ((reg & (1u << periph->shift)) == 0u) {
> -               reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
> -               if (reg & (1u << periph->shift))
> -                       return 1;
> -       }
> +       reg = readl_relaxed(base_addr + REG_SUBBLK_CLOCK_CR);
> +       if (reg & (1u << periph->shift))
> +               return 1;
> 
>         return 0;
>  }
> @@ -441,6 +437,94 @@ static int mpfs_clk_register_periphs(struct device *dev, struct mpfs_periph_hw_c
>         return 0;
>  }
> 
> +/*
> + * Peripheral clock resets
> + */
> +
> +#if IS_ENABLED(CONFIG_RESET_CONTROLLER)
> +
> +u32 mpfs_reset_read(struct device *dev)
> +{
> +       struct mpfs_clock_data *clock_data = dev_get_drvdata(dev->parent);
> +
> +       return readl_relaxed(clock_data->base + REG_SUBBLK_RESET_CR);
> +}
> +EXPORT_SYMBOL_NS_GPL(mpfs_reset_read, MCHP_CLK_MPFS);
> +
> +void mpfs_reset_write(struct device *dev, u32 val)
> +{
> +       struct mpfs_clock_data *clock_data = dev_get_drvdata(dev->parent);
> +
> +       writel_relaxed(val, clock_data->base + REG_SUBBLK_RESET_CR);
> +}
> +EXPORT_SYMBOL_NS_GPL(mpfs_reset_write, MCHP_CLK_MPFS);
> +
> +static void mpfs_reset_unregister_adev(void *_adev)
> +{
> +       struct auxiliary_device *adev = _adev;
> +
> +       auxiliary_device_delete(adev);
> +}
> +
> +static void mpfs_reset_adev_release(struct device *dev)
> +{
> +       struct auxiliary_device *adev = to_auxiliary_dev(dev);
> +
> +       auxiliary_device_uninit(adev);
> +
> +       kfree(adev);
> +}
> +
> +static struct auxiliary_device *mpfs_reset_adev_alloc(struct mpfs_clock_data *clk_data)
> +{
> +       struct auxiliary_device *adev;
> +       int ret;
> +
> +       adev = kzalloc(sizeof(*adev), GFP_KERNEL);
> +       if (!adev)
> +               return ERR_PTR(-ENOMEM);
> +
> +       adev->name = "reset-mpfs";
> +       adev->dev.parent = clk_data->dev;
> +       adev->dev.release = mpfs_reset_adev_release;
> +       adev->id = 666u;
> +
> +       ret = auxiliary_device_init(adev);
> +       if (ret) {
> +               kfree(adev);
> +               return ERR_PTR(ret);
> +       }
> +
> +       return adev;
> +}
> +
> +static int mpfs_reset_controller_register(struct mpfs_clock_data *clk_data)
> +{
> +       struct auxiliary_device *adev;
> +       int ret;
> +
> +       adev = mpfs_reset_adev_alloc(clk_data);
> +       if (IS_ERR(adev))
> +               return PTR_ERR(adev);
> +
> +       ret = auxiliary_device_add(adev);
> +       if (ret) {
> +               auxiliary_device_uninit(adev);
> +               return ret;
> +       }
> +
> +       return devm_add_action_or_reset(clk_data->dev, mpfs_reset_unregister_adev, adev);
> +}
> +
> +#else /* !CONFIG_RESET_CONTROLLER */
> +
> +static int mpfs_reset_controller_register(struct mpfs_clock_data *clk_data)
> +{
> +       return 0;
> +}
> +
> +#endif /* !CONFIG_RESET_CONTROLLER */
> +
>  static int mpfs_clk_probe(struct platform_device *pdev)
>  {
>         struct device *dev = &pdev->dev;
> @@ -465,6 +549,8 @@ static int mpfs_clk_probe(struct platform_device *pdev)
>                 return PTR_ERR(clk_data->msspll_base);
> 
>         clk_data->hw_data.num = num_clks;
> +       clk_data->dev = dev;
> +       dev_set_drvdata(dev, clk_data);
> 
>         ret = mpfs_clk_register_mssplls(dev, mpfs_msspll_clks, ARRAY_SIZE(mpfs_msspll_clks),
>                                         clk_data);
> @@ -484,14 +570,14 @@ static int mpfs_clk_probe(struct platform_device *pdev)
>         if (ret)
>                 return ret;
> 
> -       return ret;
> +       return mpfs_reset_controller_register(clk_data);
>  }
> 
>  static const struct of_device_id mpfs_clk_of_match_table[] = {
>         { .compatible = "microchip,mpfs-clkcfg", },
>         {}
>  };
> -MODULE_DEVICE_TABLE(of, mpfs_clk_match_table);
> +MODULE_DEVICE_TABLE(of, mpfs_clk_of_match_table);
> 
>  static struct platform_driver mpfs_clk_driver = {
>         .probe = mpfs_clk_probe,
> diff --git a/include/soc/microchip/mpfs.h b/include/soc/microchip/mpfs.h
> index 6466515262bd..f916dcde457f 100644
> --- a/include/soc/microchip/mpfs.h
> +++ b/include/soc/microchip/mpfs.h
> @@ -40,4 +40,12 @@ struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev);
> 
>  #endif /* if IS_ENABLED(CONFIG_POLARFIRE_SOC_SYS_CTRL) */
> 
> +#if IS_ENABLED(CONFIG_MCHP_CLK_MPFS)
> +
> +u32 mpfs_reset_read(struct device *dev);
> +
> +void mpfs_reset_write(struct device *dev, u32 val);
> +
> +#endif /* if IS_ENABLED(CONFIG_MCHP_CLK_MPFS) */
> +
>  #endif /* __SOC_MPFS_H__ */
> --
> 2.36.1
>