From: Pali Rohár <pali@xxxxxxxxxx>
Calculate baud rate value in c_*speed fields to the real values which were
set on hardware. For this operation, add a new set of methods
*_divisor_to_baud() for each chip and use them for calculating the real
baud rate values.
Each *_divisor_to_baud() method is constructed as an inverse function of
its corresponding *_baud_to_divisor() method.
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Tested-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
---
drivers/usb/serial/ftdi_sio.c | 83 +++++++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 39e8c5d06157..838acce53e69 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1167,6 +1167,23 @@ static int ftdi_sio_baud_to_divisor(int baud)
}
}
+static int ftdi_sdio_divisor_to_baud(u32 divisor)
+{
+ switch (divisor) {
+ case ftdi_sio_b300: return 300;
+ case ftdi_sio_b600: return 600;
+ case ftdi_sio_b1200: return 1200;
+ case ftdi_sio_b2400: return 2400;
+ case ftdi_sio_b4800: return 4800;
+ case ftdi_sio_b9600: return 9600;
+ case ftdi_sio_b19200: return 19200;
+ case ftdi_sio_b38400: return 38400;
+ case ftdi_sio_b57600: return 57600;
+ case ftdi_sio_b115200: return 115200;
+ default: return 9600;
+ }
+}
+
static unsigned short int ftdi_232am_baud_base_to_divisor(int baud, int base)
{
unsigned short int divisor;
@@ -1189,15 +1206,33 @@ static unsigned short int ftdi_232am_baud_base_to_divisor(int baud, int base)
return divisor;
}
+static int ftdi_232am_divisor_base_to_baud(unsigned short int divisor, int base)
+{
+ static const unsigned char divfrac_inv[4] = { 0, 4, 2, 1 };
+ unsigned int divisor3;
+
+ if (divisor == 0)
+ divisor = 1;
+ divisor3 = (GENMASK(13, 0) & divisor) << 3;
+ divisor3 |= divfrac_inv[(divisor >> 14) & 0x3];
+ return DIV_ROUND_CLOSEST(base, 2 * divisor3);
+}
+
static unsigned short int ftdi_232am_baud_to_divisor(int baud)
{
return ftdi_232am_baud_base_to_divisor(baud, 48000000);
}
+static int ftdi_232am_divisor_to_baud(unsigned short int divisor)
+{
+ return ftdi_232am_divisor_base_to_baud(divisor, 48000000);
+}
+
static u32 ftdi_232bm_baud_base_to_divisor(int baud, int base)
{
static const unsigned char divfrac[8] = { 0, 3, 2, 4, 1, 5, 6, 7 };
u32 divisor;
+
/* divisor shifted 3 bits to the left */
int divisor3 = DIV_ROUND_CLOSEST(base, 2 * baud);
if (divisor3 > GENMASK(16, 0))
@@ -1212,11 +1247,31 @@ static u32 ftdi_232bm_baud_base_to_divisor(int baud, int base)
return divisor;
}
+static int ftdi_232bm_divisor_base_to_baud(u32 divisor, int base)
+{
+ static const unsigned char divfrac_inv[8] = { 0, 4, 2, 1, 3, 5, 6, 7 };
+ u32 divisor3;
+
+ /* Deal with special cases for highest baud rates. */
+ if (divisor == 0)
+ divisor = 1; /* 1.0 */
+ else if (divisor == 1)
+ divisor = 0x4001; /* 1.5 */
+ divisor3 = (GENMASK(13, 0) & divisor) << 3;
+ divisor3 |= divfrac_inv[(divisor >> 14) & 0x7];
+ return DIV_ROUND_CLOSEST(base, 2 * divisor3);
+}
+
static u32 ftdi_232bm_baud_to_divisor(int baud)
{
return ftdi_232bm_baud_base_to_divisor(baud, 48000000);
}
+static int ftdi_232bm_divisor_to_baud(u32 divisor)
+{
+ return ftdi_232bm_divisor_base_to_baud(divisor, 48000000);
+}
+
static u32 ftdi_2232h_baud_base_to_divisor(int baud, int base)
{
static const unsigned char divfrac[8] = { 0, 3, 2, 4, 1, 5, 6, 7 };
@@ -1244,11 +1299,32 @@ static u32 ftdi_2232h_baud_base_to_divisor(int baud, int base)
return divisor;
}
+static int ftdi_2232h_divisor_base_to_baud(u32 divisor, int base)
+{
+ static const unsigned char divfrac_inv[8] = { 0, 4, 2, 1, 3, 5, 6, 7 };
+ u32 divisor3;
+
+ divisor &= GENMASK(16, 0);
+ /* Deal with special cases for highest baud rates. */
+ if (divisor == 0)
+ divisor = 1; /* 1.0 */
+ else if (divisor == 1)
+ divisor = 0x4001; /* 1.5 */
+ divisor3 = (GENMASK(13, 0) & divisor) << 3;
+ divisor3 |= divfrac_inv[(divisor >> 14) & 0x7];
+ return DIV_ROUND_CLOSEST(8 * base, 10 * divisor3);
+}
+
static u32 ftdi_2232h_baud_to_divisor(int baud)
{
return ftdi_2232h_baud_base_to_divisor(baud, 120000000);
}
+static int ftdi_2232h_divisor_to_baud(u32 divisor)
+{
+ return ftdi_2232h_divisor_base_to_baud(divisor, 120000000);
+}
+
#define set_mctrl(port, set) update_mctrl((port), (set), 0)
#define clear_mctrl(port, clear) update_mctrl((port), 0, (clear))
@@ -1342,6 +1418,7 @@ static u32 get_ftdi_divisor(struct tty_struct *tty,
}
div_okay = 0;
}
+ baud = ftdi_sdio_divisor_to_baud(div_value);
break;
case FT8U232AM: /* 8U232AM chip */
if (baud >= 183 && baud <= 3000000) {
@@ -1352,6 +1429,7 @@ static u32 get_ftdi_divisor(struct tty_struct *tty,
div_value = ftdi_232am_baud_to_divisor(baud);
div_okay = 0;
}
+ baud = ftdi_232am_divisor_to_baud(div_value);
break;
case FT232BM: /* FT232BM chip */
case FT2232C: /* FT2232C chip */
@@ -1375,22 +1453,27 @@ static u32 get_ftdi_divisor(struct tty_struct *tty,
div_value = ftdi_232bm_baud_to_divisor(baud);
div_okay = 0;
}
+ baud = ftdi_232bm_divisor_to_baud(div_value);
break;
case FT2232H: /* FT2232H chip */
case FT4232H: /* FT4232H chip */
case FT232H: /* FT232H chip */
if ((baud <= 12000000) && (baud >= 1200)) {
div_value = ftdi_2232h_baud_to_divisor(baud);
+ baud = ftdi_2232h_divisor_to_baud(div_value);
} else if (baud >= 183 && baud < 1200) {
div_value = ftdi_232bm_baud_to_divisor(baud);
+ baud = ftdi_232bm_divisor_to_baud(div_value);
} else {
dev_dbg(dev, "%s - Baud rate too high!\n", __func__);
if (old_baud >= 183 && old_baud < 1200) {
baud = old_baud;
div_value = ftdi_232bm_baud_to_divisor(baud);
+ baud = ftdi_232bm_divisor_to_baud(div_value);
} else {
baud = (old_baud >= 1200 && old_baud <= 12000000) ? old_baud : 9600;
div_value = ftdi_2232h_baud_to_divisor(baud);
+ baud = ftdi_2232h_divisor_to_baud(div_value);
}
div_okay = 0;
}
--
2.35.1
