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clarify clock_configure and make it return the correct value achieved for bad clock inputs #2225

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Merged
merged 1 commit into from
Feb 4, 2025
Merged

clarify clock_configure and make it return the correct value achieved for bad clock inputs #2225

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4 changes: 4 additions & 0 deletions src/rp2_common/hardware_clocks/clocks.c
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Original file line number Diff line number Diff line change
Expand Up @@ -102,6 +102,10 @@ bool clock_configure(clock_handle_t clock, uint32_t src, uint32_t auxsrc, uint32
return false;

uint32_t div = (uint32_t)((((uint64_t) src_freq) << CLOCKS_CLK_GPOUT0_DIV_INT_LSB) / freq);
// only clock divider of 1, or >= 2 are supported
if (div < (2u << CLOCKS_CLK_GPOUT0_DIV_INT_LSB)) {
div = (1u << CLOCKS_CLK_GPOUT0_DIV_INT_LSB);
}
uint32_t actual_freq = (uint32_t) ((((uint64_t) src_freq) << CLOCKS_CLK_GPOUT0_DIV_INT_LSB) / div);

clock_configure_internal(clock, src, auxsrc, actual_freq, div);
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13 changes: 10 additions & 3 deletions src/rp2_common/hardware_clocks/include/hardware/clocks.h
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Expand Up @@ -262,11 +262,18 @@ extern "C" {

typedef clock_num_t clock_handle_t;

/*! \brief Configure the specified clock
/*! \brief Configure the specified clock with automatic clock divisor setup
* \ingroup hardware_clocks
*
* This method allows both the src_frequency of the input clock source AND the desired
* frequency to be specified, and will set the clock divider to achieve the exact or higher frequency
* achievable, with the maximum being the src_freq.
*
* Note: That the clock hardware only support divisors of exactly 1 or 2.0->65535.0
*
* See the tables in the description for details on the possible values for clock sources.
*
*
* \param clock The clock to configure
* \param src The main clock source, can be 0.
* \param auxsrc The auxiliary clock source, which depends on which clock is being set. Can be 0
Expand All @@ -275,7 +282,7 @@ typedef clock_num_t clock_handle_t;
*/
bool clock_configure(clock_handle_t clock, uint32_t src, uint32_t auxsrc, uint32_t src_freq, uint32_t freq);

/*! \brief Configure the specified clock to use the undividded input source
/*! \brief Configure the specified clock to use the undivided input source
* \ingroup hardware_clocks
*
* See the tables in the description for details on the possible values for clock sources.
Expand All @@ -287,7 +294,7 @@ bool clock_configure(clock_handle_t clock, uint32_t src, uint32_t auxsrc, uint32
*/
void clock_configure_undivided(clock_handle_t clock, uint32_t src, uint32_t auxsrc, uint32_t src_freq);

/*! \brief Configure the specified clock to use the undividded input source
/*! \brief Configure the specified clock to use the undivided input source
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Hmmm, same 'brief' description for both clock_configure_undivided and clock_configure_int_divider - is that correct, or was it a copy'n'paste error?

* \ingroup hardware_clocks
*
* See the tables in the description for details on the possible values for clock sources.
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