Clock Gating Control

Functions
ALT_STATUS_CODE	alt_clk_clock_disable (ALT_CLK_t clk)
ALT_STATUS_CODE	alt_clk_clock_enable (ALT_CLK_t clk)
ALT_STATUS_CODE	alt_clk_is_enabled (ALT_CLK_t clk)

Detailed Description

This functional group provides gating control of selected clock signals.

When a clock is enabled, then its clock signal propogates to its respective clocked IP block(s). When a clock is disabled, then its clock signal is prevented from propogating to its respective clocked IP block(s).

The following clocks may be gated:

• Main PLL Group
  • l4_main_clk
  • l3_mp_clk
  • l4_mp_clk
  • l4_sp_clk
  • dbg_at_clk
  • dbg_clk
  • dbg_trace_clk
  • dbg_timer_clk
  • cfg_clk
  • s2f_user0_clk
• SDRAM PLL Group
  • ddr_dqs_clk
  • ddr_2x_clk
  • ddr_dq_clk
  • s2f_user2_clk
• Peripheral PLL Group
  • emac0_clk
  • emac1_clk
  • usb_mp_clk
  • spi_m_clk
  • can0_clk
  • can1_clk
  • gpio_db_clk
  • s2f_user1_clk
  • sdmmc_clk
  • nand_clk
  • nand_x_clk
  • qspi_clk

Function Documentation

alt_clk_clock_disable()

ALT_STATUS_CODE alt_clk_clock_disable

(

ALT_CLK_t

clk

)

Disable the specified clock. Once the clock is disabled, its clock signal does not propogate to its clocked elements.

Parameters

clk	The clock to disable.

Return values

ALT_E_SUCCESS	The operation was succesful.
ALT_E_ERROR	The operation failed.
ALT_E_BAD_ARG	The clk argument designates a non gated clock value.

alt_clk_clock_enable()

ALT_STATUS_CODE alt_clk_clock_enable

(

ALT_CLK_t

clk

)

Enable the specified clock. Once the clock is enabled, its clock signal propogates to its elements.

Parameters

clk	The clock to enable.

Return values

ALT_E_SUCCESS	The operation was succesful.
ALT_E_ERROR	The operation failed.
ALT_E_BAD_ARG	The clk argument designates a non gated clock value.

alt_clk_is_enabled()

ALT_STATUS_CODE alt_clk_is_enabled

(

ALT_CLK_t

clk

)

Return whether the specified clock is enabled or not.

Parameters

clk	The clock to check whether enabled or not.

Return values

ALT_E_TRUE	The clock is enabled.
ALT_E_FALSE	The clock is not enabled.
ALT_E_BAD_ARG	The clk argument designates a non gated clock value.