Messages in this thread | | | Date | Thu, 1 Jun 2023 21:21:37 +0800 | Subject | Re: [PATCH v6 2/6] drm/etnaviv: add a dedicated function to get various clocks | From | Sui Jingfeng <> |
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Hi,
On 2023/6/1 02:07, Lucas Stach wrote: >> +static int etnaviv_gpu_clk_get(struct etnaviv_gpu *gpu) >> +{ >> + struct device *dev = gpu->dev; >> + >> + if (gpu->no_clk) >> + return 0; >> + >> + gpu->clk_reg = devm_clk_get_optional(dev, "reg"); >> + DBG("clk_reg: %p", gpu->clk_reg); >> + if (IS_ERR(gpu->clk_reg)) >> + return PTR_ERR(gpu->clk_reg); >> + >> + gpu->clk_bus = devm_clk_get_optional(dev, "bus"); >> + DBG("clk_bus: %p", gpu->clk_bus); >> + if (IS_ERR(gpu->clk_bus)) >> + return PTR_ERR(gpu->clk_bus); >> + >> + gpu->clk_core = devm_clk_get(dev, "core"); >> + DBG("clk_core: %p", gpu->clk_core); >> + if (IS_ERR(gpu->clk_core)) >> + return PTR_ERR(gpu->clk_core); >> + gpu->base_rate_core = clk_get_rate(gpu->clk_core); >> + >> + gpu->clk_shader = devm_clk_get_optional(dev, "shader"); >> + DBG("clk_shader: %p", gpu->clk_shader); >> + if (IS_ERR(gpu->clk_shader)) >> + return PTR_ERR(gpu->clk_shader); >> + gpu->base_rate_shader = clk_get_rate(gpu->clk_shader); >> + >> + return 0; >> +} >> + >> static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu) >> { >> int ret; >> >> + if (gpu->no_clk) >> + return 0; >> + > I don't see why this would be needed? I have just tested, this do not needed. > If your platform doesn't provide > CONFIG_HAVE_CLK all those functions should be successful no-ops, so > there is no need to special case this in the driver.
My platform do enable CONFIG_HAVE_CLK,
for ls3a5000 + ls7a1000, my system do not provide device tree support,
that's is to say, there is no DT support.
For ls3a4000 + ls7a1000 platform, the system has DT support, but don't has CLK drivers implement toward the clock tree.
typically, our platform's firmware will do such thing(setting a default working frequency).
When I first saw etnaviv, I'm also astonishing.
I don't know why there so much clock controllable.
As far as I can understand, my system/hardware have only one clock,
It shall corresponding to the core clk.
> Or does your platform in fact provide a clk subsystem, just the GPU > clocks are managed by it? > > Also all those functions are fine with being called on a NULL clk, so > shouldn't it be enough to simply avoid calling etnaviv_gpu_clk_get() in > the PCI device case? > > Regards, > Lucas > -- Jingfeng
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