Messages in this thread | | | Date | Mon, 9 Dec 2013 16:44:53 +0800 | From | bilhuang <> | Subject | Re: [PATCH v3 2/2] cpufreq: tegra: Re-model Tegra cpufreq driver |
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On 12/06/2013 07:04 AM, Stephen Warren wrote: > On 12/05/2013 12:44 AM, Bill Huang wrote: >> Re-model Tegra cpufreq driver to support all Tegra series of SoCs. >> >> * Make tegra-cpufreq.c a generic Tegra cpufreq driver. >> * Move Tegra20 specific codes into tegra20-cpufreq.c. >> * Bind Tegra cpufreq dirver with a fake device so defer probe would work >> when we're going to get regulator in the driver to support voltage >> scaling (DVFS). > >> diff --git a/drivers/cpufreq/tegra-cpufreq.c b/drivers/cpufreq/tegra-cpufreq.c > >> @@ -91,14 +40,10 @@ static int tegra_update_cpu_speed(struct cpufreq_policy *policy, > ... >> + if (soc_config->vote_emc_on_cpu_rate) >> + soc_config->vote_emc_on_cpu_rate(rate); >> + >> + ret = soc_config->cpu_clk_set_rate(rate * 1000); >> if (ret) >> pr_err("cpu-tegra: Failed to set cpu frequency to %lu kHz\n", >> rate); > > Is there any/much shared code left in this file after this patch? It > seems like all this file does now is make each cpufreq callback function > call soc_config->the_same_function_name(). If so, wouldn't it be better > to simply implement completely separate tegar20-cpufreq and > tegra30-cpufreq drivers, and register them each directly with the > cpufreq core, to avoid this file doing all the indirection? I think this file is needed since we can shared the registration and probe logic for different SoCs. > > >> -int __init tegra_cpufreq_init(void) >> +static struct { >> + char *compat; >> + int (*init)(struct tegra_cpufreq_data *, >> + const struct tegra_cpufreq_config **); >> +} tegra_init_funcs[] = { >> + { "nvidia,tegra20", tegra20_cpufreq_init }, >> +}; >> + >> +static int tegra_cpufreq_probe(struct platform_device *pdev) > ... >> + for (i = 0; i < ARRAY_SIZE(tegra_init_funcs); i++) { >> + if (of_machine_is_compatible(tegra_init_funcs[i].compat)) { >> + ret = tegra_init_funcs[i].init(tegra_data, &soc_config); >> + if (!ret) >> + break; >> + else >> + goto out; >> + } >> } >> + if (i == ARRAY_SIZE(tegra_init_funcs)) >> + goto out; > > I think there are better ways of doing this than open-coding it. Perhaps > of_match_device() or the platform-driver equivalent could be made to work? Open coding is everywhere in OF helper functions actually. I doubt if we can use of_match_device() if we're not adding node in DT. If we're matching the platform device then we might need open coding, no? > >> +int __init tegra_cpufreq_init(void) >> +{ >> + struct platform_device_info devinfo = { .name = "tegra-cpufreq", }; >> + >> + platform_device_register_full(&devinfo); >> + >> + return 0; >> } >> EXPORT_SYMBOL(tegra_cpufreq_init); > > Perhaps instead of hard-coding the name "tegra-cpufreq" here, you could > dynamically construct the device name based on the DT's root compatible > value, register "${root_compatible}-cpufreq", e.g. > "nvidia,tegra20-cpufreq" or "nvidia,tegra30-cpufreq". That would allow > the kernel's standard device/driver matching mechanism to pick the > correct driver to instantiate. Perhaps you could even dynamically > register an OF device so that you can use of_match_device() in probe, if I guess what you meant dynamically register an OF device is registering an fake OF device by calling of_device_add(), no? If yes then what of_node should we give? > there's some advantage of having a single driver that supports N chips. >
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