Re: [PATCH 2/3] PCI: brcmstb: Add regulator support

[Jim Quinlan <james.quinlan@xxxxxxxxxxxx>]

On Wed, Feb 12, 2020 at 9:59 PM Jaedon Shin <jaedon.shin@xxxxxxxxx> wrote:
>
> ARM-based Broadcom STB SoCs have GPIO-based voltage regulator for PCIe
> turning off/on power supplies.
>
> Signed-off-by: Jaedon Shin <jaedon.shin@xxxxxxxxx>
> ---
>  drivers/gpio/gpio-brcmstb.c           | 13 ++++-
>  drivers/pci/controller/pcie-brcmstb.c | 76 +++++++++++++++++++++++++++
>  2 files changed, 88 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
> index 05e3f99ae59c..0cee5fcd2782 100644
> --- a/drivers/gpio/gpio-brcmstb.c
> +++ b/drivers/gpio/gpio-brcmstb.c
> @@ -777,7 +777,18 @@ static struct platform_driver brcmstb_gpio_driver = {
>         .remove = brcmstb_gpio_remove,
>         .shutdown = brcmstb_gpio_shutdown,
>  };
> -module_platform_driver(brcmstb_gpio_driver);
> +
> +static int __init brcmstb_gpio_init(void)
> +{
> +       return platform_driver_register(&brcmstb_gpio_driver);
> +}
> +subsys_initcall(brcmstb_gpio_init);
> +
> +static void __exit brcmstb_gpio_exit(void)
> +{
> +       platform_driver_unregister(&brcmstb_gpio_driver);
> +}
> +module_exit(brcmstb_gpio_exit);
>
>  MODULE_AUTHOR("Gregory Fong");
>  MODULE_DESCRIPTION("Driver for Broadcom BRCMSTB SoC UPG GPIO");
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index 34581a6a7313..0e0ca39a680b 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -23,6 +23,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/pci.h>
>  #include <linux/printk.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/sizes.h>
>  #include <linux/slab.h>
>  #include <linux/string.h>
> @@ -173,8 +174,79 @@ struct brcm_pcie {
>         int                     gen;
>         u64                     msi_target_addr;
>         struct brcm_msi         *msi;
> +#ifdef CONFIG_REGULATOR
> +       int                     num_regs;
> +       struct regulator        **regs;
> +#endif
>  };
Hi,
Just a nit but I would lean towards using 'regulator' as opposed to
'reg', as the 'reg' term's common association is  'register'.  You
don't seem to be anywhere near the 80-col limit on your code so that
doesn't seem to be an issue.
Thanks,
Jim
>
> +#ifdef CONFIG_REGULATOR
> +static void brcm_pcie_regulator_enable(struct brcm_pcie *pcie)
> +{
> +       int i, ret;
> +
> +       for (i = 0; i < pcie->num_regs; i++) {
> +               if (!pcie->regs[i])
> +                       continue;
> +
> +               ret = regulator_enable(pcie->regs[i]);
> +               if (ret)
> +                       dev_err(pcie->dev, "Failed to enable regulator\n");
> +       }
> +}
> +
> +static void brcm_pcie_regulator_disable(struct brcm_pcie *pcie)
> +{
> +       int i, ret;
> +
> +       for (i = 0; i < pcie->num_regs; i++) {
> +               if (!pcie->regs[i])
> +                       continue;
> +
> +               ret = regulator_disable(pcie->regs[i]);
> +               if (ret)
> +                       dev_err(pcie->dev, "Failed to disable regulator\n");
> +       }
> +}
> +
> +static void brcm_pcie_regulator_init(struct brcm_pcie *pcie)
> +{
> +       struct device_node *np = pcie->dev->of_node;
> +       struct device *dev = pcie->dev;
> +       const char *name;
> +       struct regulator *reg;
> +       int i;
> +
> +       pcie->num_regs = of_property_count_strings(np, "supply-names");
> +       if (pcie->num_regs <= 0) {
> +               pcie->num_regs = 0;
> +               return;
> +       }
> +
> +       pcie->regs = devm_kcalloc(dev, pcie->num_regs, sizeof(pcie->regs[0]),
> +                                 GFP_KERNEL);
> +       if (!pcie->regs) {
> +               pcie->num_regs = 0;
> +               return;
> +       }
> +
> +       for (i = 0; i < pcie->num_regs; i++) {
> +               if (of_property_read_string_index(np, "supply-names", i, &name))
> +                       continue;
> +
> +               reg = devm_regulator_get_optional(dev, name);
> +               if (IS_ERR(reg))
> +                       continue;
> +
> +               pcie->regs[i] = reg;
> +       }
> +}
> +#else
> +static inline void brcm_pcie_regulator_enable(struct brcm_pcie *pcie) { }
> +static inline void brcm_pcie_regulator_disable(struct brcm_pcie *pcie) { }
> +static inline void brcm_pcie_regulator_init(struct brcm_pcie *pcie) { }
> +#endif
> +
>  /*
>   * This is to convert the size of the inbound "BAR" region to the
>   * non-linear values of PCIE_X_MISC_RC_BAR[123]_CONFIG_LO.SIZE
> @@ -898,6 +970,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
>  {
>         brcm_msi_remove(pcie);
>         brcm_pcie_turn_off(pcie);
> +       brcm_pcie_regulator_disable(pcie);
>         clk_disable_unprepare(pcie->clk);
>         clk_put(pcie->clk);
>  }
> @@ -955,6 +1028,9 @@ static int brcm_pcie_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> +       brcm_pcie_regulator_init(pcie);
> +       brcm_pcie_regulator_enable(pcie);
> +
>         ret = brcm_pcie_setup(pcie);
>         if (ret)
>                 goto fail;
> --
> 2.21.0
>