From: Addy Ke <addy.ke@rock-chips.com>
To: broonie@kernel.org, heiko@sntech.de, dianders@chromium.org,
grant.likely@linaro.org, robh+dt@kernel.org, amstan@google.com,
sonnyrao@google.com
Cc: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, devicetree@vger.kernel.org,
olof@lixom.net, hj@rock-chips.com, kever.yang@rock-chips.com,
xjq@rock-chips.com, huangtao@rock-chips.com, zyw@rock-chips.com,
yzq@rock-chips.com, zhenfu.fang@rock-chips.com,
cf@rock-chips.com, zhangqing@rock-chips.com, hl@rock-chips.com,
wei.luo@rock-chips.com, Addy Ke <addy.ke@rock-chips.com>
Subject: [PATCH 1/2] spi/rockchip: fix bug that case spi can't go as fast as slave request
Date: Wed, 15 Oct 2014 19:25:49 +0800 [thread overview]
Message-ID: <1413372349-4254-1-git-send-email-addy.ke@rock-chips.com> (raw)
In-Reply-To: <1413372311-4203-1-git-send-email-addy.ke@rock-chips.com>
Because the minimum divisor in rk3x's spi controller is 2,
if spi_clk is less than 2 * sclk_out, we can't get the right divisor.
So we must set spi_clk again to match slave request.
Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
---
drivers/spi/spi-rockchip.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index f96ea8a..3044c6c 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -145,6 +145,9 @@
#define RXBUSY (1 << 0)
#define TXBUSY (1 << 1)
+/* sclk_out: spi master internal logic in rk3x can support 50Mhz */
+#define MAX_SCLK_OUT 50000000
+
enum rockchip_ssi_type {
SSI_MOTO_SPI = 0,
SSI_TI_SSP,
@@ -496,6 +499,15 @@ static void rockchip_spi_config(struct rockchip_spi *rs)
dmacr |= RF_DMA_EN;
}
+ if (WARN_ON(rs->speed > MAX_SCLK_OUT))
+ rs->speed = MAX_SCLK_OUT;
+
+ /* the minimum divsor is 2 */
+ if (rs->max_freq < 2 * rs->speed) {
+ clk_set_rate(rs->spiclk, 2 * rs->speed);
+ rs->max_freq = clk_get_rate(rs->spiclk);
+ }
+
/* div doesn't support odd number */
div = max_t(u32, rs->max_freq / rs->speed, 1);
div = (div + 1) & 0xfffe;
--
1.8.3.2
next prev parent reply other threads:[~2014-10-15 11:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-15 11:25 [PATCH 0/2] spi: fix two bugs Addy Ke
2014-10-15 11:25 ` Addy Ke [this message]
2014-10-15 13:04 ` [PATCH 1/2] spi/rockchip: fix bug that case spi can't go as fast as slave request Mark Brown
[not found] ` <20141015130452.GD27755-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2014-10-16 9:16 ` addy ke
2014-10-16 9:34 ` Mark Brown
2014-10-16 9:58 ` addy ke
2014-10-16 10:26 ` Mark Brown
2014-10-15 11:26 ` [PATCH 2/2] spi/rockchip: fix bug that cause spi transfer timed out in DMA duplex mode Addy Ke
[not found] ` <1413372378-4309-1-git-send-email-addy.ke-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2014-10-15 13:05 ` Mark Brown
[not found] ` <20141015130547.GE27755-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2014-10-16 9:26 ` addy ke
2014-10-16 9:34 ` Mark Brown
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