According to CY7C67300 specification HPI read and write cycle duration
Tcyc must be at least 6T long, where T is 1/48MHz, which is 125ns.
Without this delay fast host processor cannot write to chip registers.
Add proper ndelay to hpi_{read,write}_reg.
Signed-off-by: Max Filippov <jcmvb...@gmail.com>
---
drivers/usb/c67x00/c67x00-ll-hpi.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/c67x00/c67x00-ll-hpi.c
b/drivers/usb/c67x00/c67x00-ll-hpi.c
index 3a1ca4d..72fc34e 100644
--- a/drivers/usb/c67x00/c67x00-ll-hpi.c
+++ b/drivers/usb/c67x00/c67x00-ll-hpi.c
@@ -22,6 +22,7 @@
*/
#include <asm/byteorder.h>
+#include <linux/delay.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/usb/c67x00.h>
@@ -75,11 +76,13 @@ struct c67x00_lcp_int_data {
static inline u16 hpi_read_reg(struct c67x00_device *dev, int reg)
{
+ ndelay(125);
return __raw_readw(dev->hpi.base + reg * dev->hpi.regstep);
}
static inline void hpi_write_reg(struct c67x00_device *dev, int reg, u16 value)
{
+ ndelay(125);
__raw_writew(value, dev->hpi.base + reg * dev->hpi.regstep);
}
--
1.8.1.4
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