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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:15:13 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:15:13 +0000
commit98f739b627c5daa488e70dae1c8097aa78ca80ae (patch)
treeafd38c73d3b6b7a6567383aeeaee0536dcdcb920 /drivers/spi/spi-axi-spi-engine.c
parentAdding upstream version 6.9.9. (diff)
downloadlinux-98f739b627c5daa488e70dae1c8097aa78ca80ae.tar.xz
linux-98f739b627c5daa488e70dae1c8097aa78ca80ae.zip
Adding upstream version 6.9.10.upstream/6.9.10
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/spi/spi-axi-spi-engine.c')
-rw-r--r--drivers/spi/spi-axi-spi-engine.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c
index e358ac5b45..96a5247725 100644
--- a/drivers/spi/spi-axi-spi-engine.c
+++ b/drivers/spi/spi-axi-spi-engine.c
@@ -164,16 +164,20 @@ static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry,
}
static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
- int delay_ns, u32 sclk_hz)
+ int delay_ns, int inst_ns, u32 sclk_hz)
{
unsigned int t;
- /* negative delay indicates error, e.g. from spi_delay_to_ns() */
- if (delay_ns <= 0)
+ /*
+ * Negative delay indicates error, e.g. from spi_delay_to_ns(). And if
+ * delay is less that the instruction execution time, there is no need
+ * for an extra sleep instruction since the instruction execution time
+ * will already cover the required delay.
+ */
+ if (delay_ns < 0 || delay_ns <= inst_ns)
return;
- /* rounding down since executing the instruction adds a couple of ticks delay */
- t = DIV_ROUND_DOWN_ULL((u64)delay_ns * sclk_hz, NSEC_PER_SEC);
+ t = DIV_ROUND_UP_ULL((u64)(delay_ns - inst_ns) * sclk_hz, NSEC_PER_SEC);
while (t) {
unsigned int n = min(t, 256U);
@@ -220,10 +224,16 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry,
struct spi_device *spi = msg->spi;
struct spi_controller *host = spi->controller;
struct spi_transfer *xfer;
- int clk_div, new_clk_div;
+ int clk_div, new_clk_div, inst_ns;
bool keep_cs = false;
u8 bits_per_word = 0;
+ /*
+ * Take into account instruction execution time for more accurate sleep
+ * times, especially when the delay is small.
+ */
+ inst_ns = DIV_ROUND_UP(NSEC_PER_SEC, host->max_speed_hz);
+
clk_div = 1;
spi_engine_program_add_cmd(p, dry,
@@ -252,7 +262,7 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry,
spi_engine_gen_xfer(p, dry, xfer);
spi_engine_gen_sleep(p, dry, spi_delay_to_ns(&xfer->delay, xfer),
- xfer->effective_speed_hz);
+ inst_ns, xfer->effective_speed_hz);
if (xfer->cs_change) {
if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
@@ -262,7 +272,7 @@ static void spi_engine_compile_message(struct spi_message *msg, bool dry,
spi_engine_gen_cs(p, dry, spi, false);
spi_engine_gen_sleep(p, dry, spi_delay_to_ns(
- &xfer->cs_change_delay, xfer),
+ &xfer->cs_change_delay, xfer), inst_ns,
xfer->effective_speed_hz);
if (!list_next_entry(xfer, transfer_list)->cs_off)