diff options
| author | Emil Renner Berthing <kernel@esmil.dk> | 2018-10-31 11:57:08 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2018-11-05 11:42:32 +0000 |
| commit | 74b7efa82b11914c21e30d987ed61d3daa57ff21 (patch) | |
| tree | 61a4e3de03e958c4f7d3629362b2e31e575c4b6c /drivers/spi/spi-rockchip.c | |
| parent | 420b82f842941a32adf309ca1b193adfc77616b0 (diff) | |
| download | linux-74b7efa82b11914c21e30d987ed61d3daa57ff21.tar.bz2 | |
spi: rockchip: precompute rx sample delay
Now that we no longer potentially change spi clock
at runtime we can precompute the rx sample delay
at probe time rather than for each transfer.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-rockchip.c')
| -rw-r--r-- | drivers/spi/spi-rockchip.c | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c index d1b3ba2b1532..5fe6099ff366 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -94,6 +94,7 @@ #define CR0_BHT_8BIT 0x1 #define CR0_RSD_OFFSET 14 +#define CR0_RSD_MAX 0x3 #define CR0_FRF_OFFSET 16 #define CR0_FRF_SPI 0x0 @@ -179,7 +180,7 @@ struct rockchip_spi { u32 freq; u8 n_bytes; - u32 rsd_nsecs; + u8 rsd; const void *tx; const void *tx_end; @@ -450,13 +451,13 @@ static void rockchip_spi_config(struct rockchip_spi *rs, bool use_dma) { u32 dmacr = 0; - int rsd = 0; u32 cr0 = CR0_FRF_SPI << CR0_FRF_OFFSET | CR0_BHT_8BIT << CR0_BHT_OFFSET | CR0_SSD_ONE << CR0_SSD_OFFSET | CR0_EM_BIG << CR0_EM_OFFSET; + cr0 |= rs->rsd << CR0_RSD_OFFSET; cr0 |= (rs->n_bytes << CR0_DFS_OFFSET); cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET; @@ -474,20 +475,6 @@ static void rockchip_spi_config(struct rockchip_spi *rs, dmacr |= RF_DMA_EN; } - /* Rx sample delay is expressed in parent clock cycles (max 3) */ - rsd = DIV_ROUND_CLOSEST(rs->rsd_nsecs * (rs->freq >> 8), - 1000000000 >> 8); - if (!rsd && rs->rsd_nsecs) { - pr_warn_once("rockchip-spi: %u Hz are too slow to express %u ns delay\n", - rs->freq, rs->rsd_nsecs); - } else if (rsd > 3) { - rsd = 3; - pr_warn_once("rockchip-spi: %u Hz are too fast to express %u ns delay, clamping at %u ns\n", - rs->freq, rs->rsd_nsecs, - rsd * 1000000000U / rs->freq); - } - cr0 |= rsd << CR0_RSD_OFFSET; - writel_relaxed(cr0, rs->regs + ROCKCHIP_SPI_CTRLR0); if (rs->n_bytes == 1) @@ -620,8 +607,21 @@ static int rockchip_spi_probe(struct platform_device *pdev) rs->freq = clk_get_rate(rs->spiclk); if (!of_property_read_u32(pdev->dev.of_node, "rx-sample-delay-ns", - &rsd_nsecs)) - rs->rsd_nsecs = rsd_nsecs; + &rsd_nsecs)) { + /* rx sample delay is expressed in parent clock cycles (max 3) */ + u32 rsd = DIV_ROUND_CLOSEST(rsd_nsecs * (rs->freq >> 8), + 1000000000 >> 8); + if (!rsd) { + dev_warn(rs->dev, "%u Hz are too slow to express %u ns delay\n", + rs->freq, rsd_nsecs); + } else if (rsd > CR0_RSD_MAX) { + rsd = CR0_RSD_MAX; + dev_warn(rs->dev, "%u Hz are too fast to express %u ns delay, clamping at %u ns\n", + rs->freq, rsd_nsecs, + CR0_RSD_MAX * 1000000000U / rs->freq); + } + rs->rsd = rsd; + } rs->fifo_len = get_fifo_len(rs); if (!rs->fifo_len) { |