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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2018-05-29 15:09:45 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2018-07-12 11:59:48 +1000 |
| commit | edc2485148d20c56c67d9ceec4d645c18d795a8d (patch) | |
| tree | 390a672350fb53614b78aee47bccccfdd531ffee | |
| parent | a2e7da86cc392417b0d9f605b28038aae80b002f (diff) | |
| download | lwn-edc2485148d20c56c67d9ceec4d645c18d795a8d.tar.gz lwn-edc2485148d20c56c67d9ceec4d645c18d795a8d.zip | |
fsi: master-gpio: Rename and adjust send delay
What the driver called "FSI_GPIO_PRIME_SLAVE_CLOCKS" is what
the FSI spec calls tSendDelay and should be 16 clocks by
default.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
| -rw-r--r-- | drivers/fsi/fsi-master-gpio.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c index 084e9da8d151..3f846dada626 100644 --- a/drivers/fsi/fsi-master-gpio.c +++ b/drivers/fsi/fsi-master-gpio.c @@ -18,6 +18,7 @@ #define FSI_GPIO_STD_DLY 1 /* Standard pin delay in nS */ #define FSI_ECHO_DELAY_CLOCKS 16 /* Number clocks for echo delay */ +#define FSI_SEND_DELAY_CLOCKS 16 /* Number clocks for send delay */ #define FSI_PRE_BREAK_CLOCKS 50 /* Number clocks to prep for break */ #define FSI_BREAK_CLOCKS 256 /* Number of clocks to issue break */ #define FSI_POST_BREAK_CLOCKS 16000 /* Number clocks to set up cfam */ @@ -48,7 +49,6 @@ #define FSI_GPIO_CRC_SIZE 4 #define FSI_GPIO_MSG_ID_SIZE 2 #define FSI_GPIO_MSG_RESPID_SIZE 2 -#define FSI_GPIO_PRIME_SLAVE_CLOCKS 20 #define LAST_ADDR_INVALID 0x1 @@ -535,9 +535,12 @@ retry: if (busy_count > 0) trace_fsi_master_gpio_poll_response_busy(master, busy_count); fail: - /* Clock the slave enough to be ready for next operation */ + /* + * tSendDelay clocks, avoids signal reflections when switching + * from receive of response back to send of data. + */ local_irq_save(flags); - clock_zeros(master, FSI_GPIO_PRIME_SLAVE_CLOCKS); + clock_zeros(master, FSI_SEND_DELAY_CLOCKS); local_irq_restore(flags); return rc; |