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SubjectRe: [PATCH v6 2/2] PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver
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Il 27/05/22 13:00, Johnson Wang ha scritto:
> We introduce a devfreq driver for the MediaTek Cache Coherent Interconnect
> (CCI) used by some MediaTek SoCs.
>
> In this driver, we use the passive devfreq driver to get target frequencies
> and adjust voltages accordingly. In MT8183 and MT8186, the MediaTek CCI
> is supplied by the same regulators with the little core CPUs.
>
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> Signed-off-by: Johnson Wang <johnson.wang@mediatek.com>
> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> This patch depends on "devfreq-testing"[1].
> [1]https://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git/log/?h=devfreq-testing
> ---
> drivers/devfreq/Kconfig | 10 +
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/mtk-cci-devfreq.c | 441 ++++++++++++++++++++++++++++++
> 3 files changed, 452 insertions(+)
> create mode 100644 drivers/devfreq/mtk-cci-devfreq.c
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 87eb2b837e68..9754d8b31621 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -120,6 +120,16 @@ config ARM_TEGRA_DEVFREQ
> It reads ACTMON counters of memory controllers and adjusts the
> operating frequencies and voltages with OPP support.
>
> +config ARM_MEDIATEK_CCI_DEVFREQ
> + tristate "MEDIATEK CCI DEVFREQ Driver"
> + depends on ARM_MEDIATEK_CPUFREQ || COMPILE_TEST
> + select DEVFREQ_GOV_PASSIVE
> + help
> + This adds a devfreq driver for MediaTek Cache Coherent Interconnect
> + which is shared the same regulators with the cpu cluster. It can track
> + buck voltages and update a proper CCI frequency. Use the notification
> + to get the regulator status.
> +
> config ARM_RK3399_DMC_DEVFREQ
> tristate "ARM RK3399 DMC DEVFREQ Driver"
> depends on (ARCH_ROCKCHIP && HAVE_ARM_SMCCC) || \
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 0b6be92a25d9..bf40d04928d0 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o
> obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o
> obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o
> obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o
> +obj-$(CONFIG_ARM_MEDIATEK_CCI_DEVFREQ) += mtk-cci-devfreq.o
> obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
> obj-$(CONFIG_ARM_SUN8I_A33_MBUS_DEVFREQ) += sun8i-a33-mbus.o
> obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o
> diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c
> new file mode 100644
> index 000000000000..df42da35b312
> --- /dev/null
> +++ b/drivers/devfreq/mtk-cci-devfreq.c
> @@ -0,0 +1,441 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2022 MediaTek Inc.
> + */
> +

..snip..

> +};
> +
> +static int mtk_ccifreq_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mtk_ccifreq_drv *drv;
> + struct devfreq_passive_data *passive_data;
> + struct dev_pm_opp *opp;
> + unsigned long rate, opp_volt;
> + int ret;
> +
> + drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
> + if (!drv)
> + return -ENOMEM;
> +
> + drv->dev = dev;
> + drv->soc_data = (const struct mtk_ccifreq_platform_data *)
> + of_device_get_match_data(&pdev->dev);
> + mutex_init(&drv->reg_lock);
> + platform_set_drvdata(pdev, drv);
> +
> + drv->cci_clk = devm_clk_get(dev, "cci");
> + if (IS_ERR(drv->cci_clk)) {
> + ret = PTR_ERR(drv->cci_clk);
> + return dev_err_probe(dev, ret,
> + "failed to get cci clk: %d\n", ret);
> + }
> +
> + drv->inter_clk = devm_clk_get(dev, "intermediate");
> + if (IS_ERR(drv->inter_clk)) {
> + ret = PTR_ERR(drv->inter_clk);
> + return dev_err_probe(dev, ret,
> + "failed to get intermediate clk: %d\n", ret);
> + }
> +
> + drv->proc_reg = devm_regulator_get_optional(dev, "proc");

In the devicetree binding for this driver, the "proc" regulator is *not* optional,
but here you're using devm_regulator_get_optional.

If this is not optional, you should use devm_regulator_get() instead.

> + if (IS_ERR(drv->proc_reg)) {
> + ret = PTR_ERR(drv->proc_reg);
> + return dev_err_probe(dev, ret,
> + "failed to get proc regulator: %d\n", ret);

There's no need to print ret... dev_err_probe() takes care of that for you already:
in this case, you're printing the value of ret twice.

> + }
> +
> + ret = regulator_enable(drv->proc_reg);

If you move this call after the devm_regulator_get_optional() call for the sram
vreg, you will be able to use dev_err_probe for the latter as well.

> + if (ret) {
> + dev_err(dev, "failed to enable proc regulator\n");

Why aren't you using dev_err_probe here, like you've done for the other instances?

> + return ret;
> + }
> +
> + drv->sram_reg = devm_regulator_get_optional(dev, "sram");
> + if (IS_ERR(drv->sram_reg))
> + drv->sram_reg = NULL;

When you use regulator_get_optional() (including the devm_ variant of it), you
shall return an error, if there's any... that's what the _optional() is for.

if (IS_ERR(drv->sram_reg))
return dev_err_probe(dev, PTR_ERR(drv->proc_reg),
"failed to get sram regulator");

> + else {
> + ret = regulator_enable(drv->sram_reg);
> + if (ret) {
> + dev_err(dev, "failed to enable sram regulator\n");
> + goto out_free_resources;
> + }
> + }
> +

Regards,
Angelo


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