On 2020-04-02 1:48 AM, Chanwoo Choi wrote: > On 4/1/20 11:20 PM, Leonard Crestez wrote: >> On 2020-04-01 1:55 AM, Chanwoo Choi wrote: >>> Hi, >>> >>> Looks good to me. I added the comments. >>> But, it need to add the dt binding documentation for this device. >> >> DT bindings were included: >> >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fpatch%2F11458981%2F&data=02%7C01%7Cleonard.crestez%40nxp.com%7C7381d117a4d1468cd2c608d7d68ecfac%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637213781167514099&sdata=Qu8x14cXnuxlwOT2SlUOf%2FLgCVWbnJRKA4TBjMIWQeA%3D&reserved=0 > > The dt-binding document for this driver is required under > Documentation/devicetree/binding/devfreq. Bindings for imx8m-ddrc were at one point posted for devicetree/bindings/devfreq but Rob Herring suggested to move them under "memory-controller" instead and I expect same logic makes sense here. Link to previous discussion: https://patchwork.kernel.org/patch/11221919/ DT bindings should try to describe "hardware" rather than "drivers" and an "interconnect" is a class of hardware while "devfreq" isn't. Not only that but the main noc has properties parsed by interconnect driver. > It is difficult to catch where is the dt-binding document > for this driver for who don't know the detailed history > of this driver. I don't said that add the duplicate documentation > But, at least the some document have to point out the reference. What I usually do to find information about a device is grep for the compat string in the entire tree. >>> The old email of Artur Świgoń is not used. On next time, >>> use following the new email address Because when I reply the mail, >>> always show the fail message from thunderbird due to the Artur's old email. >>> <a.swigon@xxxxxxxxxxxxxxxxxxx> -> <a.swigon@xxxxxxxxxxx> >> >> Yeah, I received multiple bounces because of this. >> >>> On 3/26/20 11:16 AM, Leonard Crestez wrote: >>>> Add initial support for dynamic frequency switching on pieces of the imx >>>> interconnect fabric. >>>> >>>> All this driver does is set a clk rate based on an opp table, it does >>>> not map register areas. >>>> >>>> Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx> >>>> --- >>>> drivers/devfreq/Kconfig | 9 +++ >>>> drivers/devfreq/Makefile | 1 + >>>> drivers/devfreq/imx-bus.c | 142 ++++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 152 insertions(+) >>>> create mode 100644 drivers/devfreq/imx-bus.c >>>> >>>> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig >>>> index 0b1df12e0f21..44d26192ddc4 100644 >>>> --- a/drivers/devfreq/Kconfig >>>> +++ b/drivers/devfreq/Kconfig >>>> @@ -99,10 +99,19 @@ config ARM_IMX8M_DDRC_DEVFREQ >>>> select DEVFREQ_GOV_USERSPACE >>>> help >>>> This adds the DEVFREQ driver for the i.MX8M DDR Controller. It allows >>>> adjusting DRAM frequency. >>>> >>>> +config ARM_IMX_BUS_DEVFREQ >>>> + tristate "i.MX Generic Bus DEVFREQ Driver" >>>> + depends on ARCH_MXC || COMPILE_TEST >>>> + select DEVFREQ_GOV_PASSIVE >>>> + select DEVFREQ_GOV_USERSPACE >>> >>> Maybe, you would update it by using passive governor? >>> But, in this version, it doesn't handle the any passive governor. >> >> dropped >> >>>> + help >>>> + This adds the generic DEVFREQ driver for i.MX interconnects. It >>>> + allows adjusting NIC/NOC frequency. >>>> + >>>> config ARM_TEGRA_DEVFREQ >>>> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver" >>>> depends on ARCH_TEGRA_3x_SOC || ARCH_TEGRA_114_SOC || \ >>>> ARCH_TEGRA_132_SOC || ARCH_TEGRA_124_SOC || \ >>>> ARCH_TEGRA_210_SOC || \ >>>> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile >>>> index 3eb4d5e6635c..3ca1ad0ecb97 100644 >>>> --- a/drivers/devfreq/Makefile >>>> +++ b/drivers/devfreq/Makefile >>>> @@ -7,10 +7,11 @@ obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o >>>> obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o >>>> obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o >>>> >>>> # DEVFREQ Drivers >>>> obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o >>>> +obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o >>> >>> The ARM_IMX_BUS_DEVFREQ config is under ARM_IMX8M_DDRC_DEVFREQ >>> and imx-bus.o is over imx8m-ddrc.o. Need to edit the sequence. >> >> Reordered kconfig to match. 8M_DDRC sorts before _BUS alphabetically but >> it's pettier this way, and matches tegra. >> >>>> obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o >>>> obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o >>>> obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o >>>> obj-$(CONFIG_ARM_TEGRA20_DEVFREQ) += tegra20-devfreq.o >>>> >>>> diff --git a/drivers/devfreq/imx-bus.c b/drivers/devfreq/imx-bus.c >>>> new file mode 100644 >>>> index 000000000000..285e0f1ae6b1 >>>> --- /dev/null >>>> +++ b/drivers/devfreq/imx-bus.c >>>> @@ -0,0 +1,142 @@ >>>> +// SPDX-License-Identifier: GPL-2.0 >>>> +/* >>>> + * Copyright 2019 NXP >>>> + */ >>>> + >>>> +#include <linux/clk.h> >>>> +#include <linux/devfreq.h> >>>> +#include <linux/device.h> >>>> +#include <linux/module.h> >>>> +#include <linux/of_device.h> >>>> +#include <linux/pm_opp.h> >>>> +#include <linux/platform_device.h> >>>> +#include <linux/slab.h> >>>> + >>>> +struct imx_bus { >>>> + struct devfreq_dev_profile profile; >>>> + struct devfreq *devfreq; >>>> + struct clk *clk; >>>> + struct devfreq_passive_data passive_data; >>> >>> This patch doesn't touch the passive_data. >> >> dropped >> >>>> +}; >>>> + >>>> +static int imx_bus_target(struct device *dev, >>>> + unsigned long *freq, u32 flags) >>>> +{ >>>> + struct imx_bus *priv = dev_get_drvdata(dev); >>>> + struct dev_pm_opp *new_opp; >>>> + unsigned long new_freq; >>>> + int ret; >>>> + >>>> + new_opp = devfreq_recommended_opp(dev, freq, flags); >>>> + if (IS_ERR(new_opp)) { >>>> + ret = PTR_ERR(new_opp); >>>> + dev_err(dev, "failed to get recommended opp: %d\n", ret); >>>> + return ret; >>>> + } >>>> + new_freq = dev_pm_opp_get_freq(new_opp); >>> >>> It doesn't need. Because the new frequency is stored to 'freq' >>> by calling devfreq_recommended_opp(). >> >> fixed >> >>>> + dev_pm_opp_put(new_opp); >>>> + >>>> + return clk_set_rate(priv->clk, new_freq); >>> >>> nitpick. you can use dev_pm_opp_set_rate(). But, I'm not forcing to use it. >> >> Switched to dev_pm_opp_set_rate. >> >> It might be interesting to add regulators control later, on some chips >> the main NOC can run at different voltages. >> >>> >>>> +} >>>> + >>>> +static int imx_bus_get_cur_freq(struct device *dev, unsigned long *freq) >>>> +{ >>>> + struct imx_bus *priv = dev_get_drvdata(dev); >>>> + >>>> + *freq = clk_get_rate(priv->clk); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static int imx_bus_get_dev_status(struct device *dev, >>>> + struct devfreq_dev_status *stat) >>>> +{ >>>> + struct imx_bus *priv = dev_get_drvdata(dev); >>>> + >>>> + stat->busy_time = 0; >>>> + stat->total_time = 0; >>>> + stat->current_frequency = clk_get_rate(priv->clk); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static void imx_bus_exit(struct device *dev) >>>> +{ >>>> + dev_pm_opp_of_remove_table(dev); >>>> +} >>>> + >>>> +static int imx_bus_probe(struct platform_device *pdev) >>>> +{ >>>> + struct device *dev = &pdev->dev; >>>> + struct imx_bus *priv; >>>> + const char *gov = DEVFREQ_GOV_USERSPACE; >>>> + int ret; >>>> + >>>> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); >>>> + if (!priv) >>>> + return -ENOMEM; >>>> + >>>> + /* >>>> + * Fetch the clock to adjust but don't explictly enable. >>> >>> Need to fix typo. >>> s/explictly/explicitly >> >> fixed >> >>>> + * >>>> + * For imx bus clock clk_set_rate is safe no matter if the clock is on >>>> + * or off and some peripheral side-buses might be off unless enabled by >>>> + * drivers for devices on those specific buses. >>>> + * >>>> + * Rate adjustment on a disabled bus clock just takes effect later. >>>> + */ >>>> + priv->clk = devm_clk_get(dev, NULL); >>>> + if (IS_ERR(priv->clk)) { >>>> + ret = PTR_ERR(priv->clk); >>>> + dev_err(dev, "failed to fetch clk: %d\n", ret); >>>> + return ret; >>>> + } >>>> + platform_set_drvdata(pdev, priv); >>>> + >>>> + ret = dev_pm_opp_of_add_table(dev); >>>> + if (ret < 0) { >>>> + dev_err(dev, "failed to get OPP table\n"); >>>> + return ret; >>>> + } >>>> + >>>> + priv->profile.polling_ms = 1000; >>>> + priv->profile.target = imx_bus_target; >>>> + priv->profile.get_dev_status = imx_bus_get_dev_status; >>>> + priv->profile.exit = imx_bus_exit; >>>> + priv->profile.get_cur_freq = imx_bus_get_cur_freq; >>>> + priv->profile.initial_freq = clk_get_rate(priv->clk); >>>> + >>>> + priv->devfreq = devm_devfreq_add_device(dev, &priv->profile, >>>> + gov, NULL); >>>> + if (IS_ERR(priv->devfreq)) { >>>> + ret = PTR_ERR(priv->devfreq); >>>> + dev_err(dev, "failed to add devfreq device: %d\n", ret); >>>> + goto err; >>>> + } >>>> + >>>> + return 0; >>>> + >>>> +err: >>>> + dev_pm_opp_of_remove_table(dev); >>>> + return ret; >>>> +} >>>> + >>>> +static const struct of_device_id imx_bus_of_match[] = { >>>> + { .compatible = "fsl,imx8m-noc", }, >>>> + { .compatible = "fsl,imx8m-nic", }, >>>> + { /* sentinel */ }, >>>> +}; >>>> +MODULE_DEVICE_TABLE(of, imx_bus_of_match); >>>> + >>>> +static struct platform_driver imx_bus_platdrv = { >>>> + .probe = imx_bus_probe, >>>> + .driver = { >>>> + .name = "imx-bus-devfreq", >>>> + .of_match_table = of_match_ptr(imx_bus_of_match), >>>> + }, >>>> +}; >>>> +module_platform_driver(imx_bus_platdrv); >>>> + >>>> +MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver"); >>>> +MODULE_AUTHOR("Leonard Crestez <leonard.crestez@xxxxxxx>"); >>>> +MODULE_LICENSE("GPL v2"); >>>> >>> >>> >> >> >> >> > >
