diff options
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/sh-sci.c | 42 |
1 files changed, 19 insertions, 23 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index c3a193616484..d89d4b7576cf 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1860,20 +1860,24 @@ static void sci_shutdown(struct uart_port *port) sci_free_irq(s); } -static unsigned int sci_scbrr_calc(struct sci_port *s, unsigned int bps, - unsigned long freq) +/* calculate sample rate, BRR, and clock select */ +static void sci_scbrr_calc(struct sci_port *s, unsigned int bps, + unsigned long freq, int *brr, unsigned int *srr, + unsigned int *cks) { - return DIV_ROUND_CLOSEST(freq, s->sampling_rate * bps) - 1; -} - -/* calculate sample rate, BRR, and clock select for HSCIF */ -static void sci_baud_calc_hscif(struct sci_port *s, unsigned int bps, - unsigned long freq, int *brr, - unsigned int *srr, unsigned int *cks) -{ - unsigned int sr, br, prediv, scrate, c; + unsigned int min_sr, max_sr, shift, sr, br, prediv, scrate, c; int err, min_err = INT_MAX; + if (s->sampling_rate) { + min_sr = max_sr = s->sampling_rate; + shift = 0; + } else { + /* HSCIF has a variable sample rate */ + min_sr = 8; + max_sr = 32; + shift = 1; + } + /* * Find the combination of sample rate and clock select with the * smallest deviation from the desired baud rate. @@ -1889,10 +1893,10 @@ static void sci_baud_calc_hscif(struct sci_port *s, unsigned int bps, * (|D - 0.5| / N * (1 + F))| * NOTE: Usually, treat D for 0.5, F is 0 by this calculation. */ - for (sr = 32; sr >= 8; sr--) { + for (sr = max_sr; sr >= min_sr; sr--) { for (c = 0; c <= 3; c++) { /* integerized formulas from HSCIF documentation */ - prediv = sr * (1 << (2 * c + 1)); + prediv = sr * (1 << (2 * c + shift)); /* * We need to calculate: @@ -1974,16 +1978,8 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, max_baud = port->uartclk ? port->uartclk / 16 : 115200; baud = uart_get_baud_rate(port, termios, old, 0, max_baud); - if (likely(baud && port->uartclk)) { - if (s->cfg->type == PORT_HSCIF) { - sci_baud_calc_hscif(s, baud, port->uartclk, &t, &srr, - &cks); - } else { - t = sci_scbrr_calc(s, baud, port->uartclk); - for (cks = 0; t >= 256 && cks <= 3; cks++) - t >>= 2; - } - } + if (likely(baud && port->uartclk)) + sci_scbrr_calc(s, baud, port->uartclk, &t, &srr, &cks); sci_port_enable(s); |