Commit e983da27 authored by A.s. Dong's avatar A.s. Dong Committed by Stephen Boyd
Browse files

clk: fractional-divider: add CLK_FRAC_DIVIDER_ZERO_BASED flag support 



Adding CLK_FRAC_DIVIDER_ZERO_BASED flag to indicate the numerator and
denominator value in register are start from 0.

This can be used to support frac dividers like below:
Divider output clock = Divider input clock x [(frac +1) / (div +1)]
where frac/div in register is:
000b - Divide by 1.
001b - Divide by 2.
010b - Divide by 3.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: default avatarDong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 40468079

drivers/clk/clk-fractional-divider.c

+10 −0
Original line number Diff line number Diff line
@@ -40,6 +40,11 @@ static unsigned long clk_fd_recalc_rate(struct clk_hw *hw, 
	m = (val & fd->mmask) >> fd->mshift;

	n = (val & fd->nmask) >> fd->nshift;



	if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) {

		m++;

		n++;

	}



	if (!n || !m)

		return parent_rate;
@@ -103,6 +108,11 @@ static int clk_fd_set_rate(struct clk_hw *hw, unsigned long rate, 
			GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0),

			&m, &n);



	if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) {

		m--;

		n--;

	}



	if (fd->lock)

		spin_lock_irqsave(fd->lock, flags);

	else

include/linux/clk-provider.h

+8 −0
Original line number Diff line number Diff line
@@ -601,6 +601,12 @@ void clk_hw_unregister_fixed_factor(struct clk_hw *hw); 
 * @lock:	register lock

 *

 * Clock with adjustable fractional divider affecting its output frequency.

 *

 * Flags:

 * CLK_FRAC_DIVIDER_ZERO_BASED - by default the numerator and denominator

 *	is the value read from the register. If CLK_FRAC_DIVIDER_ZERO_BASED

 *	is set then the numerator and denominator are both the value read

 *	plus one.

 */

struct clk_fractional_divider {

	struct clk_hw	hw;
@@ -620,6 +626,8 @@ struct clk_fractional_divider { 


#define to_clk_fd(_hw) container_of(_hw, struct clk_fractional_divider, hw)



#define CLK_FRAC_DIVIDER_ZERO_BASED		BIT(0)



extern const struct clk_ops clk_fractional_divider_ops;

struct clk *clk_register_fractional_divider(struct device *dev,

		const char *name, const char *parent_name, unsigned long flags,

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