[PATCH v2 5/5] fpga manager: cyclone-ps-spi: make delay variable
From: Joshua Clayton <hidden>
Date: 2016-10-28 16:57:08
Also in:
linux-arm-kernel, lkml
Subsystem:
fpga manager framework, the rest · Maintainers:
Moritz Fischer, Xu Yilun, Linus Torvalds
The status pin may not show ready in the time described in the Altetera manual. check the value several times before giving up For the hardware I am working on, the status pin takes 250 us, 5 times as long as described by Altera. Signed-off-by: Joshua Clayton <redacted> --- drivers/fpga/cyclone-ps-spi.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/fpga/cyclone-ps-spi.c b/drivers/fpga/cyclone-ps-spi.c
index 4b70d5c..c368223 100644
--- a/drivers/fpga/cyclone-ps-spi.c
+++ b/drivers/fpga/cyclone-ps-spi.c@@ -20,6 +20,7 @@ #define FPGA_RESET_TIME 50 /* time in usecs to trigger FPGA config */ -#define FPGA_MIN_DELAY 250 /* min usecs to wait for config status */ +#define FPGA_MIN_DELAY 50 /* min usecs to wait for config status */ +#define FPGA_MAX_DELAY 1000 /* max usecs to wait for config status */ struct cyclonespi_conf { struct gpio_desc *config;
@@ -42,6 +43,7 @@ static int cyclonespi_write_init(struct fpga_manager *mgr, u32 flags, const char *buf, size_t count) { struct cyclonespi_conf *conf = (struct cyclonespi_conf *)mgr->priv; + int i; if (flags & FPGA_MGR_PARTIAL_RECONFIG) { dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
@@ -56,13 +58,14 @@ static int cyclonespi_write_init(struct fpga_manager *mgr, u32 flags, } gpiod_set_value(conf->config, 1); - usleep_range(FPGA_MIN_DELAY, FPGA_MIN_DELAY + 20); - if (gpiod_get_value(conf->status) == 0) { - dev_err(&mgr->dev, "Status pin not ready.\n"); - return -EIO; + for (i = 0; i < (FPGA_MAX_DELAY / FPGA_MIN_DELAY); i++) { + usleep_range(FPGA_MIN_DELAY, FPGA_MIN_DELAY + 20); + if (gpiod_get_value(conf->status)) + return 0; } - return 0; + dev_err(&mgr->dev, "Status pin not ready.\n"); + return -EIO; } static void rev_buf(void *buf, size_t len)
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2.7.4