| Message ID | 1468682123-1434-1-git-send-email-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | Rejected, archived |
| Delegated to: | Stephen Boyd |
| Headers | show |
On Sun, 2016-07-17 at 00:15:23 +0900, Masahiro Yamada wrote: > The "clock-output-names" property is useful for generic clock > providers such as fixed-clock, fixed-factor-clock, etc. > > On the other hand, it should not be used for really SoC-specific > clock providers like this one. As you see in "enum zynq_clk" in > this driver, it is written as if it already knows all the clock > names. Besides, this is instantiated only once, so no clock name > conflict would happen even if the clock names are hard-coded in the > driver. > > The device tree (arch/arm/boot/dts/zynq-7000.dtsi) will be fixed > later. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> IIRC, this was the only way to allow circular clock routing. E.g. there are use-cases that route an FCLK back into the PS to use it as input for the GEM. With the introduction of deferred probing this might all be possible now but it would be good to verify that this kind of circular clock routing still works with this change. Sören -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Jul 17, 2016 at 12:15:23AM +0900, Masahiro Yamada wrote: > The "clock-output-names" property is useful for generic clock > providers such as fixed-clock, fixed-factor-clock, etc. > > On the other hand, it should not be used for really SoC-specific > clock providers like this one. As you see in "enum zynq_clk" in > this driver, it is written as if it already knows all the clock > names. Besides, this is instantiated only once, so no clock name > conflict would happen even if the clock names are hard-coded in the > driver. > > The device tree (arch/arm/boot/dts/zynq-7000.dtsi) will be fixed > later. This should be done now so dts files and docs are in sync. > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > This patch was tested on Zynq Zedboard. > > > .../devicetree/bindings/clock/zynq-7000.txt | 13 ------------- > drivers/clk/zynq/clkc.c | 21 ++++++++++++--------- > 2 files changed, 12 insertions(+), 22 deletions(-) Acked-by: Rob Herring <robh@kernel.org> -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, 2016-07-17 at 09:11:10 -0700, Sören Brinkmann wrote: > On Sun, 2016-07-17 at 00:15:23 +0900, Masahiro Yamada wrote: > > The "clock-output-names" property is useful for generic clock > > providers such as fixed-clock, fixed-factor-clock, etc. > > > > On the other hand, it should not be used for really SoC-specific > > clock providers like this one. As you see in "enum zynq_clk" in > > this driver, it is written as if it already knows all the clock > > names. Besides, this is instantiated only once, so no clock name > > conflict would happen even if the clock names are hard-coded in the > > driver. > > > > The device tree (arch/arm/boot/dts/zynq-7000.dtsi) will be fixed > > later. > > > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > > IIRC, this was the only way to allow circular clock routing. E.g. there > are use-cases that route an FCLK back into the PS to use it as input for > the GEM. With the introduction of deferred probing this might all be > possible now but it would be good to verify that this kind of circular > clock routing still works with this change. Yep, this breaks this kind of routing. E.g. if you remove the clk-output-names from the DT and add an EMIO clock input like this: clocks = <&clkc 15>; clock-names = "gem1_emio_clk"; the code will no longer be able to correctly obtain the clock name for that input. Sören -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/clock/zynq-7000.txt b/Documentation/devicetree/bindings/clock/zynq-7000.txt index d93746c..562ff3f 100644 --- a/Documentation/devicetree/bindings/clock/zynq-7000.txt +++ b/Documentation/devicetree/bindings/clock/zynq-7000.txt @@ -17,8 +17,6 @@ Required properties: - reg : SLCR offset and size taken via syscon < 0x100 0x100 > - ps-clk-frequency : Frequency of the oscillator providing ps_clk in HZ (usually 33 MHz oscillators are used for Zynq platforms) - - clock-output-names : List of strings used to name the clock outputs. Shall be - a list of the outputs given below. Optional properties: - clocks : as described in the clock bindings @@ -93,17 +91,6 @@ Example: compatible = "xlnx,ps7-clkc"; ps-clk-frequency = <33333333>; reg = <0x100 0x100>; - clock-output-names = "armpll", "ddrpll", "iopll", "cpu_6or4x", - "cpu_3or2x", "cpu_2x", "cpu_1x", "ddr2x", "ddr3x", - "dci", "lqspi", "smc", "pcap", "gem0", "gem1", - "fclk0", "fclk1", "fclk2", "fclk3", "can0", "can1", - "sdio0", "sdio1", "uart0", "uart1", "spi0", "spi1", - "dma", "usb0_aper", "usb1_aper", "gem0_aper", - "gem1_aper", "sdio0_aper", "sdio1_aper", - "spi0_aper", "spi1_aper", "can0_aper", "can1_aper", - "i2c0_aper", "i2c1_aper", "uart0_aper", "uart1_aper", - "gpio_aper", "lqspi_aper", "smc_aper", "swdt", - "dbg_trc", "dbg_apb"; # optional props clocks = <&clkc 16>, <&clk_foo>; clock-names = "gem1_emio_clk", "can_mio_clk_23"; diff --git a/drivers/clk/zynq/clkc.c b/drivers/clk/zynq/clkc.c index 88a2cab..c5a3ed3 100644 --- a/drivers/clk/zynq/clkc.c +++ b/drivers/clk/zynq/clkc.c @@ -68,6 +68,18 @@ enum zynq_clk { i2c0_aper, i2c1_aper, uart0_aper, uart1_aper, gpio_aper, lqspi_aper, smc_aper, swdt, dbg_trc, dbg_apb, clk_max}; +static const char * const clk_output_name[] = { + "armpll", "ddrpll", "iopll", + "cpu_6or4x", "cpu_3or2x", "cpu_2x", "cpu_1x", + "ddr2x", "ddr3x", "dci", + "lqspi", "smc", "pcap", "gem0", "gem1", "fclk0", "fclk1", "fclk2", "fclk3", "can0", "can1", + "sdio0", "sdio1", "uart0", "uart1", "spi0", "spi1", "dma", + "usb0_aper", "usb1_aper", "gem0_aper", "gem1_aper", + "sdio0_aper", "sdio1_aper", "spi0_aper", "spi1_aper", "can0_aper", "can1_aper", + "i2c0_aper", "i2c1_aper", "uart0_aper", "uart1_aper", "gpio_aper", "lqspi_aper", + "smc_aper", "swdt", "dbg_trc", "dbg_apb" +}; + static struct clk *ps_clk; static struct clk *clks[clk_max]; static struct clk_onecell_data clk_data; @@ -231,7 +243,6 @@ static void __init zynq_clk_setup(struct device_node *np) struct clk *clk; char *clk_name; unsigned int fclk_enable = 0; - const char *clk_output_name[clk_max]; const char *cpu_parents[4]; const char *periph_parents[4]; const char *swdt_ext_clk_mux_parents[2]; @@ -240,14 +251,6 @@ static void __init zynq_clk_setup(struct device_node *np) pr_info("Zynq clock init\n"); - /* get clock output names from DT */ - for (i = 0; i < clk_max; i++) { - if (of_property_read_string_index(np, "clock-output-names", - i, &clk_output_name[i])) { - pr_err("%s: clock output name not in DT\n", __func__); - BUG(); - } - } cpu_parents[0] = clk_output_name[armpll]; cpu_parents[1] = clk_output_name[armpll]; cpu_parents[2] = clk_output_name[ddrpll];
The "clock-output-names" property is useful for generic clock providers such as fixed-clock, fixed-factor-clock, etc. On the other hand, it should not be used for really SoC-specific clock providers like this one. As you see in "enum zynq_clk" in this driver, it is written as if it already knows all the clock names. Besides, this is instantiated only once, so no clock name conflict would happen even if the clock names are hard-coded in the driver. The device tree (arch/arm/boot/dts/zynq-7000.dtsi) will be fixed later. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- This patch was tested on Zynq Zedboard. .../devicetree/bindings/clock/zynq-7000.txt | 13 ------------- drivers/clk/zynq/clkc.c | 21 ++++++++++++--------- 2 files changed, 12 insertions(+), 22 deletions(-)