| Message ID | 1467876237-12183-1-git-send-email-andi.shyti@samsung.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | d9aaf1dc984a448ae5630e53a611a8b3489d1f8d |
| Headers | show |
On 07/07/2016 09:23 AM, Andi Shyti wrote: > When the clock is coming from the cmu it is not required to be > disabled and then re-enabled in order to change the rate. > > Besides, some exynos chipsets (e.g. exynos5433) do not deliver > any to the SFR if one from the pclk ("spi" in this case) or sclk > ("busclk") is disabled. > > Remove the clock disabling/enabling to avoid falling into this > situation. > > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> > Signed-off-by: Andi Shyti <andi.shyti@samsung.com> > --- > > Hi, > > This patch has been tested by me and Sylwester on Trats2 > (exynos4412) and tm2(e) (exynos5433) boards, for big data > (which use dma transfer) and small data. > > It also fixes in exynos5433 a synchronus abort caused by the fact > that the pclk (spi) doesn't get delivered if the sclk is disabled > (busclk) > > Thanks, > Andi > > drivers/spi/spi-s3c64xx.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, > if (sdd->port_conf->clk_from_cmu) { > - /* Configure Clock */ > - /* There is half-multiplier before the SPI */ > clk_set_rate(sdd->src_clk, sdd->cur_speed * 2); sorry, I will re-send it because I should not remove the comments above.... in the future someone might wonder why it's multiplied by 2. That's called auto review and auto-nack :) Andi > - /* Enable Clock */ > - clk_prepare_enable(sdd->src_clk); > } else { > /* Configure Clock */ > val = readl(regs + S3C64XX_SPI_CLK_CFG); > -- > 2.8.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jul 07, 2016 at 06:58:41PM +0900, Andi Shyti wrote: > sorry, I will re-send it because I should not remove the comments > above.... in the future someone might wonder why it's multiplied > by 2. I already applied and published this, can you please send an incremental patch fixing the issue?
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c index 048c900..c719e73 100644 --- a/drivers/spi/spi-s3c64xx.c +++ b/drivers/spi/spi-s3c64xx.c @@ -577,9 +577,7 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd) u32 val; /* Disable Clock */ - if (sdd->port_conf->clk_from_cmu) { - clk_disable_unprepare(sdd->src_clk); - } else { + if (!sdd->port_conf->clk_from_cmu) { val = readl(regs + S3C64XX_SPI_CLK_CFG); val &= ~S3C64XX_SPI_ENCLK_ENABLE; writel(val, regs + S3C64XX_SPI_CLK_CFG); @@ -622,11 +620,7 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd) writel(val, regs + S3C64XX_SPI_MODE_CFG); if (sdd->port_conf->clk_from_cmu) { - /* Configure Clock */ - /* There is half-multiplier before the SPI */ clk_set_rate(sdd->src_clk, sdd->cur_speed * 2); - /* Enable Clock */ - clk_prepare_enable(sdd->src_clk); } else { /* Configure Clock */ val = readl(regs + S3C64XX_SPI_CLK_CFG);
When the clock is coming from the cmu it is not required to be disabled and then re-enabled in order to change the rate. Besides, some exynos chipsets (e.g. exynos5433) do not deliver any to the SFR if one from the pclk ("spi" in this case) or sclk ("busclk") is disabled. Remove the clock disabling/enabling to avoid falling into this situation. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Andi Shyti <andi.shyti@samsung.com> --- Hi, This patch has been tested by me and Sylwester on Trats2 (exynos4412) and tm2(e) (exynos5433) boards, for big data (which use dma transfer) and small data. It also fixes in exynos5433 a synchronus abort caused by the fact that the pclk (spi) doesn't get delivered if the sclk is disabled (busclk) Thanks, Andi drivers/spi/spi-s3c64xx.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)