diff options
Diffstat (limited to 'drivers/usb/c67x00/c67x00-ll-hpi.c')
| -rw-r--r-- | drivers/usb/c67x00/c67x00-ll-hpi.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/usb/c67x00/c67x00-ll-hpi.c b/drivers/usb/c67x00/c67x00-ll-hpi.c index 3a1ca4dfc83..b58151841e1 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> @@ -62,8 +63,8 @@ struct c67x00_lcp_int_data { * HPI implementation * * The c67x00 chip also support control via SPI or HSS serial - * interfaces. However, this driver assumes that register access can - * be performed from IRQ context. While this is a safe assuption with + * interfaces. However, this driver assumes that register access can + * be performed from IRQ context. While this is a safe assumption with * the HPI interface, it is not true for the serial interfaces. */ @@ -73,13 +74,22 @@ struct c67x00_lcp_int_data { #define HPI_ADDR 2 #define HPI_STATUS 3 +/* + * According to CY7C67300 specification (tables 140 and 141) HPI read and + * write cycle duration Tcyc must be at least 6T long, where T is 1/48MHz, + * which is 125ns. + */ +#define HPI_T_CYC_NS 125 + static inline u16 hpi_read_reg(struct c67x00_device *dev, int reg) { + ndelay(HPI_T_CYC_NS); 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(HPI_T_CYC_NS); __raw_writew(value, dev->hpi.base + reg * dev->hpi.regstep); } |