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: Nariman Poushin nariman@opensource.wolfsonmicro.com --- drivers/base/regmap/regmap.c | 65 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 59 insertions(+), 6 deletions(-)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 0a849ee..a67473c2 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -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" @@ -47,6 +48,17 @@ static int _regmap_bus_reg_write(void *context, unsigned int reg, static int _regmap_bus_raw_write(void *context, unsigned int reg, unsigned int val);
+static void regmap_sequence_delay(unsigned int delay_us) +{ + /* For small delays it isn't worth setting up the hrtimers + * so fall back on udelay + */ + if (delay_us < 10) + udelay(delay_us); + else + usleep_range(delay_us, delay_us * 2); +} + bool regmap_reg_in_ranges(unsigned int reg, const struct regmap_range *ranges, unsigned int nranges) @@ -1819,10 +1831,12 @@ 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++) { @@ -1838,16 +1852,48 @@ 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) + regmap_sequence_delay(regs[i].delay_us); + base += n; n = 0; - } - ret = _regmap_select_page(map, &base[n].reg, range, 1); - if (ret != 0) - return ret; + + 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); @@ -1866,6 +1912,9 @@ 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) + regmap_sequence_delay(regs[i].delay_us); } return 0; } @@ -1905,8 +1954,12 @@ 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);