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Commit 2de9d600 authored by Nariman Poushin's avatar Nariman Poushin Committed by Mark Brown
Browse files

regmap: Apply optional delay in multi_reg_write/register_patch 



Add an optional delay_us field in reg_sequence to allow the client to
specify a delay (in microseconds) to be applied after any given write
in a sequence of writes.

We treat a delay in a sequence the same way we treat a page change as
they are logically similar in that you can coalesce all write before
a delay (in the same way you can coalesce all writes before a page
change is needed)

Signed-off-by: default avatarNariman Poushin <nariman@opensource.wolfsonmicro.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 8019ff6c

drivers/base/regmap/regmap.c

+48 −6
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/of.h>

#include <linux/rbtree.h>

#include <linux/sched.h>

#include <linux/delay.h>



#define CREATE_TRACE_POINTS

#include "trace.h"
@@ -1807,10 +1808,12 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map, 
	int i, n;

	struct reg_sequence *base;

	unsigned int this_page = 0;

	unsigned int page_change = 0;

	/*

	 * the set of registers are not neccessarily in order, but

	 * since the order of write must be preserved this algorithm

	 * chops the set each time the page changes

	 * chops the set each time the page changes. This also applies

	 * if there is a delay required at any point in the sequence.

	 */

	base = regs;

	for (i = 0, n = 0; i < num_regs; i++, n++) {
@@ -1826,16 +1829,48 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map, 
				this_page = win_page;

			if (win_page != this_page) {

				this_page = win_page;

				page_change = 1;

			}

		}



		/* If we have both a page change and a delay make sure to

		 * write the regs and apply the delay before we change the

		 * page.

		 */



		if (page_change || regs[i].delay_us) {



				/* For situations where the first write requires

				 * a delay we need to make sure we don't call

				 * raw_multi_reg_write with n=0

				 * This can't occur with page breaks as we

				 * never write on the first iteration

				 */

				if (regs[i].delay_us && i == 0)

					n = 1;



				ret = _regmap_raw_multi_reg_write(map, base, n);

				if (ret != 0)

					return ret;



				if (regs[i].delay_us)

					udelay(regs[i].delay_us);



				base += n;

				n = 0;

			}

			ret = _regmap_select_page(map, &base[n].reg, range, 1);



				if (page_change) {

					ret = _regmap_select_page(map,

								  &base[n].reg,

								  range, 1);

					if (ret != 0)

						return ret;



					page_change = 0;

				}



		}



	}

	if (n > 0)

		return _regmap_raw_multi_reg_write(map, base, n);
@@ -1854,6 +1889,9 @@ static int _regmap_multi_reg_write(struct regmap *map, 
			ret = _regmap_write(map, regs[i].reg, regs[i].def);

			if (ret != 0)

				return ret;



			if (regs[i].delay_us)

				udelay(regs[i].delay_us);

		}

		return 0;

	}
@@ -1893,8 +1931,12 @@ static int _regmap_multi_reg_write(struct regmap *map, 
	for (i = 0; i < num_regs; i++) {

		unsigned int reg = regs[i].reg;

		struct regmap_range_node *range;



		/* Coalesce all the writes between a page break or a delay

		 * in a sequence

		 */

		range = _regmap_range_lookup(map, reg);

		if (range) {

		if (range || regs[i].delay_us) {

			size_t len = sizeof(struct reg_sequence)*num_regs;

			struct reg_sequence *base = kmemdup(regs, len,

							   GFP_KERNEL);

include/linux/regmap.h

+4 −1
Original line number Diff line number Diff line
@@ -51,14 +51,17 @@ struct reg_default { 
};



/**

 * Register/value pairs for sequences of writes

 * Register/value pairs for sequences of writes with an optional delay in

 * microseconds to be applied after each write.

 *

 * @reg: Register address.

 * @def: Register value.

 * @delay_us: Delay to be applied after the register write in microseconds

 */

struct reg_sequence {

	unsigned int reg;

	unsigned int def;

	unsigned int delay_us;

};



#ifdef CONFIG_REGMAP