diff options
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/spi/spi_s3c24xx.c | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c index e0d44af4745a..590be85c8f3d 100644 --- a/drivers/spi/spi_s3c24xx.c +++ b/drivers/spi/spi_s3c24xx.c | |||
@@ -111,6 +111,7 @@ static int s3c24xx_spi_setupxfer(struct spi_device *spi, | |||
111 | unsigned int bpw; | 111 | unsigned int bpw; |
112 | unsigned int hz; | 112 | unsigned int hz; |
113 | unsigned int div; | 113 | unsigned int div; |
114 | unsigned long clk; | ||
114 | 115 | ||
115 | bpw = t ? t->bits_per_word : spi->bits_per_word; | 116 | bpw = t ? t->bits_per_word : spi->bits_per_word; |
116 | hz = t ? t->speed_hz : spi->max_speed_hz; | 117 | hz = t ? t->speed_hz : spi->max_speed_hz; |
@@ -120,20 +121,16 @@ static int s3c24xx_spi_setupxfer(struct spi_device *spi, | |||
120 | return -EINVAL; | 121 | return -EINVAL; |
121 | } | 122 | } |
122 | 123 | ||
123 | div = clk_get_rate(hw->clk) / hz; | 124 | clk = clk_get_rate(hw->clk); |
124 | 125 | div = DIV_ROUND_UP(clk, hz * 2) - 1; | |
125 | /* is clk = pclk / (2 * (pre+1)), or is it | ||
126 | * clk = (pclk * 2) / ( pre + 1) */ | ||
127 | |||
128 | div /= 2; | ||
129 | |||
130 | if (div > 0) | ||
131 | div -= 1; | ||
132 | 126 | ||
133 | if (div > 255) | 127 | if (div > 255) |
134 | div = 255; | 128 | div = 255; |
135 | 129 | ||
136 | dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", div, hz); | 130 | dev_dbg(&spi->dev, "setting pre-scaler to %d (wanted %d, got %ld)\n", |
131 | div, hz, clk / (2 * (div + 1))); | ||
132 | |||
133 | |||
137 | writeb(div, hw->regs + S3C2410_SPPRE); | 134 | writeb(div, hw->regs + S3C2410_SPPRE); |
138 | 135 | ||
139 | spin_lock(&hw->bitbang.lock); | 136 | spin_lock(&hw->bitbang.lock); |