Messages in this thread Patch in this message | | | From | Guru Das Srinagesh <> | Subject | [PATCH v7 01/13] clk: pwm: Use 64-bit division macros for period and duty cycle | Date | Mon, 9 Mar 2020 12:35:04 -0700 |
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Because period and duty cycle are defined in the PWM framework structs as ints with units of nanoseconds, the maximum time duration that can be set is limited to ~2.147 seconds. Redefining them as u64 values will enable larger time durations to be set.
As a first step, prepare drivers to handle the switch to u64 period and duty_cycle by replacing division operations involving pwm period and duty cycle with their 64-bit equivalents as appropriate. The actual switch to u64 period and duty_cycle follows as a separate patch.
Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL macros: - DIV_ROUND_UP_ULL - DIV_ROUND_CLOSEST_ULL - div_u64
Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use DIV64_* macros: - DIV64_U64_ROUND_CLOSEST - div64_u64
Cc: Michael Turquette <mturquette@baylibre.com> Cc: Stephen Boyd <sboyd@kernel.org> Cc: linux-clk@vger.kernel.org
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org> --- drivers/clk/clk-pwm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c index 87fe0b0e..7b1f7a0 100644 --- a/drivers/clk/clk-pwm.c +++ b/drivers/clk/clk-pwm.c @@ -89,7 +89,7 @@ static int clk_pwm_probe(struct platform_device *pdev) } if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate)) - clk_pwm->fixed_rate = NSEC_PER_SEC / pargs.period; + clk_pwm->fixed_rate = div64_u64(NSEC_PER_SEC, pargs.period); if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate && pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) { -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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