From: Guenter Roeck <linux@roeck-us.net> To: linux-spi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>, Guenter Roeck <linux@roeck-us.net>, Axel Lin <axel.lin@ingics.com> Subject: [PATCH] spi: sc18is602: Don't be that restrictive with the maximum transfer speed Date: Sun, 16 Mar 2014 18:47:50 -0700 [thread overview] Message-ID: <1395020870-18107-1-git-send-email-linux@roeck-us.net> (raw) Commit 09e99bca8 (spi: sc18is602: Convert to let spi core validate transfer speed) made the maximum transfer speed much more restrictive than before. The transfer speed used to be adjusted to 1/4 of the chip clock rate if a higher transfer speed was requested. Now such transfers are simply rejected. With default settings, this causes, for example, a transfer request at 2 mbps to be rejected because the maximum speed with the default chip clock is 1.843 mbps. This is unnecessarily restrictive and causes unnecessary failures. Loosen the limit to accept transfers up to 50% of the clock rate and adjust the speed as needed when setting up the actualt transfer. Cc: Axel Lin <axel.lin@ingics.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- This patch applies to the tip of linux-next. drivers/spi/spi-sc18is602.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-sc18is602.c b/drivers/spi/spi-sc18is602.c index 237f2e7..f0e55aa 100644 --- a/drivers/spi/spi-sc18is602.c +++ b/drivers/spi/spi-sc18is602.c @@ -297,7 +297,7 @@ static int sc18is602_probe(struct i2c_client *client, master->transfer_one_message = sc18is602_transfer_one; master->dev.of_node = np; master->min_speed_hz = hw->freq / 128; - master->max_speed_hz = hw->freq / 4; + master->max_speed_hz = hw->freq / 2; error = devm_spi_register_master(dev, master); if (error) -- 1.7.9.7
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From: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> To: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>, Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org> Subject: [PATCH] spi: sc18is602: Don't be that restrictive with the maximum transfer speed Date: Sun, 16 Mar 2014 18:47:50 -0700 [thread overview] Message-ID: <1395020870-18107-1-git-send-email-linux@roeck-us.net> (raw) Commit 09e99bca8 (spi: sc18is602: Convert to let spi core validate transfer speed) made the maximum transfer speed much more restrictive than before. The transfer speed used to be adjusted to 1/4 of the chip clock rate if a higher transfer speed was requested. Now such transfers are simply rejected. With default settings, this causes, for example, a transfer request at 2 mbps to be rejected because the maximum speed with the default chip clock is 1.843 mbps. This is unnecessarily restrictive and causes unnecessary failures. Loosen the limit to accept transfers up to 50% of the clock rate and adjust the speed as needed when setting up the actualt transfer. Cc: Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org> Signed-off-by: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> --- This patch applies to the tip of linux-next. drivers/spi/spi-sc18is602.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-sc18is602.c b/drivers/spi/spi-sc18is602.c index 237f2e7..f0e55aa 100644 --- a/drivers/spi/spi-sc18is602.c +++ b/drivers/spi/spi-sc18is602.c @@ -297,7 +297,7 @@ static int sc18is602_probe(struct i2c_client *client, master->transfer_one_message = sc18is602_transfer_one; master->dev.of_node = np; master->min_speed_hz = hw->freq / 128; - master->max_speed_hz = hw->freq / 4; + master->max_speed_hz = hw->freq / 2; error = devm_spi_register_master(dev, master); if (error) -- 1.7.9.7 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next reply other threads:[~2014-03-17 1:48 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-03-17 1:47 Guenter Roeck [this message] 2014-03-17 1:47 ` [PATCH] spi: sc18is602: Don't be that restrictive with the maximum transfer speed Guenter Roeck 2014-03-17 2:07 ` Axel Lin 2014-03-17 2:07 ` Axel Lin 2014-03-17 3:53 ` Guenter Roeck 2014-03-17 3:53 ` Guenter Roeck 2014-03-17 11:27 ` Mark Brown 2014-03-17 11:27 ` Mark Brown 2014-03-17 11:52 ` Mark Brown 2014-03-17 11:52 ` Mark Brown 2014-03-17 13:25 ` Guenter Roeck 2014-03-17 13:25 ` Guenter Roeck
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