[PATCH v3] clk: change clk_ops' ->determine_rate() prototype
From: Stephen Boyd <hidden>
Date: 2015-06-03 23:37:39
Also in:
linux-clk, linux-mips, linux-omap, lkml
On 05/20, Boris Brezillon wrote:
Clock rates are stored in an unsigned long field, but ->determine_rate() (which returns a rounded rate from a requested one) returns a long value (errors are reported using negative error codes), which can lead to long overflow if the clock rate exceed 2Ghz. Change ->determine_rate() prototype to return 0 or an error code, and pass a pointer to a clk_rate_request structure containing the expected target rate and the rate constraints imposed by clk users. The clk_rate_request structure might be extended in the future to contain other kind of constraints like the rounding policy, the maximum clock inaccuracy or other things that are not yet supported by the CCF (power consumption constraints ?). Signed-off-by: Boris Brezillon <redacted> CC: Jonathan Corbet <corbet@lwn.net> CC: Tony Lindgren <tony@atomide.com> CC: Ralf Baechle <redacted> CC: "Emilio L?pez" <emilio@elopez.com.ar> CC: Maxime Ripard <redacted> CC: Tero Kristo <redacted> CC: linux-doc at vger.kernel.org CC: linux-kernel at vger.kernel.org CC: linux-arm-kernel at lists.infradead.org CC: linux-omap at vger.kernel.org CC: linux-mips at linux-mips.org --- Hi Stephen, This patch is based on clk-next and contains the changes you suggested in your previous review. It was tested on sama5d4 and compile tested on several ARM platforms (those enabled in multi_v7_defconfig).
Thanks. I think we should wait until the next -rc1 drops to apply the patch for the next merge window. That will make it least likely to conflict with other trees, and we can provide it on a stable branch should there be clock providers going through other trees somewhere. Please remind me if I forget.
quoted hunk ↗ jump to hunk
@@ -1186,15 +1191,21 @@ EXPORT_SYMBOL_GPL(__clk_determine_rate); */ unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) { - unsigned long min_rate; - unsigned long max_rate; + + struct clk_rate_request req; + int ret; if (!clk) return 0; - clk_core_get_boundaries(clk->core, &min_rate, &max_rate); + clk_core_get_boundaries(clk->core, &req.min_rate, &req.max_rate); + req.rate = rate; + + ret = clk_core_round_rate_nolock(clk->core, &req); + if (ret) + return ret;
This returns a negative int for unsigned long. Is that intentional? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project