forked from Minki/linux
668c45df36
Add DT binding documentation for lpc1850-cgu driver. Signed-off-by: Joachim Eastwood <manabian@gmail.com> Signed-off-by: Michael Turquette <mturquette@baylibre.com>
132 lines
4.0 KiB
Plaintext
132 lines
4.0 KiB
Plaintext
* NXP LPC1850 Clock Generation Unit (CGU)
|
|
|
|
The CGU generates multiple independent clocks for the core and the
|
|
peripheral blocks of the LPC18xx. Each independent clock is called
|
|
a base clock and itself is one of the inputs to the two Clock
|
|
Control Units (CCUs) which control the branch clocks to the
|
|
individual peripherals.
|
|
|
|
The CGU selects the inputs to the clock generators from multiple
|
|
clock sources, controls the clock generation, and routes the outputs
|
|
of the clock generators through the clock source bus to the output
|
|
stages. Each output stage provides an independent clock source and
|
|
corresponds to one of the base clocks for the LPC18xx.
|
|
|
|
- Above text taken from NXP LPC1850 User Manual.
|
|
|
|
|
|
This binding uses the common clock binding:
|
|
Documentation/devicetree/bindings/clock/clock-bindings.txt
|
|
|
|
Required properties:
|
|
- compatible:
|
|
Should be "nxp,lpc1850-cgu"
|
|
- reg:
|
|
Shall define the base and range of the address space
|
|
containing clock control registers
|
|
- #clock-cells:
|
|
Shall have value <1>. The permitted clock-specifier values
|
|
are the base clock numbers defined below.
|
|
- clocks:
|
|
Shall contain a list of phandles for the external input
|
|
sources to the CGU. The list shall be in the following
|
|
order: xtal, 32khz, enet_rx_clk, enet_tx_clk, gp_clkin.
|
|
- clock-indices:
|
|
Shall be an ordered list of numbers defining the base clock
|
|
number provided by the CGU.
|
|
- clock-output-names:
|
|
Shall be an ordered list of strings defining the names of
|
|
the clocks provided by the CGU.
|
|
|
|
Which base clocks that are available on the CGU depends on the
|
|
specific LPC part. Base clocks are numbered from 0 to 27.
|
|
|
|
Number: Name: Description:
|
|
0 BASE_SAFE_CLK Base safe clock (always on) for WWDT
|
|
1 BASE_USB0_CLK Base clock for USB0
|
|
2 BASE_PERIPH_CLK Base clock for Cortex-M0SUB subsystem,
|
|
SPI, and SGPIO
|
|
3 BASE_USB1_CLK Base clock for USB1
|
|
4 BASE_CPU_CLK System base clock for ARM Cortex-M core
|
|
and APB peripheral blocks #0 and #2
|
|
5 BASE_SPIFI_CLK Base clock for SPIFI
|
|
6 BASE_SPI_CLK Base clock for SPI
|
|
7 BASE_PHY_RX_CLK Base clock for Ethernet PHY Receive clock
|
|
8 BASE_PHY_TX_CLK Base clock for Ethernet PHY Transmit clock
|
|
9 BASE_APB1_CLK Base clock for APB peripheral block # 1
|
|
10 BASE_APB3_CLK Base clock for APB peripheral block # 3
|
|
11 BASE_LCD_CLK Base clock for LCD
|
|
12 BASE_ADCHS_CLK Base clock for ADCHS
|
|
13 BASE_SDIO_CLK Base clock for SD/MMC
|
|
14 BASE_SSP0_CLK Base clock for SSP0
|
|
15 BASE_SSP1_CLK Base clock for SSP1
|
|
16 BASE_UART0_CLK Base clock for UART0
|
|
17 BASE_UART1_CLK Base clock for UART1
|
|
18 BASE_UART2_CLK Base clock for UART2
|
|
19 BASE_UART3_CLK Base clock for UART3
|
|
20 BASE_OUT_CLK Base clock for CLKOUT pin
|
|
24-21 - Reserved
|
|
25 BASE_AUDIO_CLK Base clock for audio system (I2S)
|
|
26 BASE_CGU_OUT0_CLK Base clock for CGU_OUT0 clock output
|
|
27 BASE_CGU_OUT1_CLK Base clock for CGU_OUT1 clock output
|
|
|
|
BASE_PERIPH_CLK and BASE_SPI_CLK is only available on LPC43xx.
|
|
BASE_ADCHS_CLK is only available on LPC4370.
|
|
|
|
|
|
Example board file:
|
|
|
|
/ {
|
|
clocks {
|
|
xtal: xtal {
|
|
compatible = "fixed-clock";
|
|
#clock-cells = <0>;
|
|
clock-frequency = <12000000>;
|
|
};
|
|
|
|
xtal32: xtal32 {
|
|
compatible = "fixed-clock";
|
|
#clock-cells = <0>;
|
|
clock-frequency = <32768>;
|
|
};
|
|
|
|
enet_rx_clk: enet_rx_clk {
|
|
compatible = "fixed-clock";
|
|
#clock-cells = <0>;
|
|
clock-frequency = <0>;
|
|
clock-output-names = "enet_rx_clk";
|
|
};
|
|
|
|
enet_tx_clk: enet_tx_clk {
|
|
compatible = "fixed-clock";
|
|
#clock-cells = <0>;
|
|
clock-frequency = <0>;
|
|
clock-output-names = "enet_tx_clk";
|
|
};
|
|
|
|
gp_clkin: gp_clkin {
|
|
compatible = "fixed-clock";
|
|
#clock-cells = <0>;
|
|
clock-frequency = <0>;
|
|
clock-output-names = "gp_clkin";
|
|
};
|
|
};
|
|
|
|
soc {
|
|
cgu: clock-controller@40050000 {
|
|
compatible = "nxp,lpc1850-cgu";
|
|
reg = <0x40050000 0x1000>;
|
|
#clock-cells = <1>;
|
|
clocks = <&xtal>, <&creg_clk 1>, <&enet_rx_clk>, <&enet_tx_clk>, <&gp_clkin>;
|
|
};
|
|
|
|
/* A CGU and CCU clock consumer */
|
|
lcdc: lcdc@40008000 {
|
|
...
|
|
clocks = <&cgu BASE_LCD_CLK>, <&ccu1 CLK_CPU_LCD>;
|
|
clock-names = "clcdclk", "apb_pclk";
|
|
...
|
|
};
|
|
};
|
|
};
|