[PATCH] ARM: clk: add clk-asm9260 driver
From: Mike Turquette <hidden>
Date: 2015-01-19 17:23:06
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lkml
Quoting Oleksij Rempel (2015-01-15 01:45:32)
Am 15.01.2015 um 00:02 schrieb Mike Turquette:quoted
Quoting Oleksij Rempel (2015-01-08 00:59:27)quoted
diff --git a/drivers/clk/clk-asm9260.c b/drivers/clk/clk-asm9260.c new file mode 100644 index 0000000..6b1c220 --- /dev/null +++ b/drivers/clk/clk-asm9260.c<snip>quoted
+static const char *clk_names[] = { + [REFCLK] = "oscillator", + [SYSPLL] = "pll", + [I2S0_MCLK] = "i2s0_mclk", + [I2S1_MCLK] = "i2s1_mclk", + [RTC_OSC] = "rtc_osc", + [USB_PLL] = "usb_pll", +};Why keep this list of names? Only clk_names[REFCLK] is used below and it is overwritten by the name supplied by DT.Ok.quoted
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+static void __init asm9260_acc_init(struct device_node *np) +{ + struct clk *clk; + u32 rate; + int n; + u32 accuracy = 0; + + base = of_io_request_and_map(np, 0, np->name); + if (!base) + panic("%s: unable to map resource", np->name); + + /* register pll */ + rate = (ioread32(base + HW_SYSPLLCTRL) & 0xffff) * 1000000; + + clk_names[REFCLK] = of_clk_get_parent_name(np, 0); + accuracy = clk_get_accuracy(__clk_lookup(clk_names[REFCLK])); + clk = clk_register_fixed_rate_with_accuracy(NULL, clk_names[SYSPLL], + clk_names[REFCLK], 0, rate, accuracy);This is different. Why do the PLLs inherit REFCLKs accuracy? Please see __clk_recalc_accuracies in drivers/clk/clk.c if you haven't already. We propagate accuracy through the clock tree already.clk_register_fixed_rate overwrite accuracy to 0. If i use clk_register_fixed_rate, then half of my clocks has accuracy = 0.
Ah, interesting. This is a bug that should be fixed. If a fixed-rate clock has a parent with a non-zero accuracy then we should propagate that accuracy value at registration-time. I'll look into this soon and your solution is fine for now. We can always clean it up later.
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+ + if (IS_ERR(clk)) + panic("%s: can't register REFCLK. Check DT!", np->name); +<snip>quoted
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+ + /* register clk-provider */ + clk_data.clks = clks; + clk_data.clk_num = MAX_CLKS; + of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data); + return; +fail: + iounmap(base); +} +CLK_OF_DECLARE(asm9260_acc, "alphascale,asm9260-clock-controller", + asm9260_acc_init);Where is the DT binding definition for this clock provider? Thanks, Mikedo you mean this patch? http://lists.infradead.org/pipermail/linux-arm-kernel/2014-October/293147.html (probably not last version) Should i resend it to you?
No need to resend. DT binding description looks fine (you can add my Reviewed-by if it is not yet merged), but I like to make sure that the code doesn't get merged before the binding definition. Regards, Mike
-- Regards, Oleksij