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spi: spi-fsl-lpspi: Some calculation improvements

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Merge series from Stefan Wahren <wahrenst@gmx.net>:

This series contains some improvements for spi-fsl-lpspi which are
related to the calculations within fsl_lpspi_set_bitrate.
This commit is contained in:
Mark Brown 2024-10-01 12:16:13 +01:00
commit e8d2b5bd60
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GPG Key ID: 24D68B725D5487D0
1 changed files with 11 additions and 4 deletions
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15
drivers/spi/spi-fsl-lpspi.c
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@ -92,6 +92,7 @@ struct lpspi_config {
u8 prescale;
u16 mode;
u32 speed_hz;
u32 effective_speed_hz;
};
struct fsl_lpspi_data {
@ -315,9 +316,10 @@ static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi)
static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
{
struct lpspi_config config = fsl_lpspi->config;
unsigned int perclk_rate, scldiv, div;
unsigned int perclk_rate, div;
u8 prescale_max;
u8 prescale;
int scldiv;
perclk_rate = clk_get_rate(fsl_lpspi->clk_per);
prescale_max = fsl_lpspi->devtype_data->prescale_max;
@ -338,19 +340,22 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
for (prescale = 0; prescale <= prescale_max; prescale++) {
scldiv = div / (1 << prescale) - 2;
if (scldiv < 256) {
if (scldiv >= 0 && scldiv < 256) {
fsl_lpspi->config.prescale = prescale;
break;
}
}
if (scldiv >= 256)
if (scldiv < 0 || scldiv >= 256)
return -EINVAL;
writel(scldiv | (scldiv << 8) | ((scldiv >> 1) << 16),
fsl_lpspi->base + IMX7ULP_CCR);
dev_dbg(fsl_lpspi->dev, "perclk=%d, speed=%d, prescale=%d, scldiv=%d\n",
fsl_lpspi->config.effective_speed_hz = perclk_rate / (scldiv + 2) *
(1 << prescale);
dev_dbg(fsl_lpspi->dev, "perclk=%u, speed=%u, prescale=%u, scldiv=%d\n",
perclk_rate, config.speed_hz, prescale, scldiv);
return 0;
@ -749,6 +754,8 @@ static int fsl_lpspi_transfer_one(struct spi_controller *controller,
if (ret < 0)
return ret;
t->effective_speed_hz = fsl_lpspi->config.effective_speed_hz;
fsl_lpspi_set_cmd(fsl_lpspi);
fsl_lpspi->is_first_byte = false;