Patch "spi: orion: Fix maximum baud rates for Armada 370/XP" has been added to the 4.0-stable tree
Subsystems (2)
This is a note to let you know that I've just added the patch titled
spi: orion: Fix maximum baud rates for Armada 370/XP
to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-orion-fix-maximum-baud-rates-for-armada-370-xp.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
ce2f6ea1cbd41d78224f703af980a6ceeb0eb56aMon Sep 17 00:00:00 2001
From: Gregory CLEMENT <[email protected]>
Date: Tue, 26 May 2015 11:44:42 +0200
Subject: spi: orion: Fix maximum baud rates for Armada 370/XP
From: Gregory CLEMENT <[email protected]>
commit ce2f6ea1cbd41d78224f703af980a6ceeb0eb56a upstream.
The commit df59fa7f4bca "spi: orion: support armada extended baud rates" was too optimistic for the maximum baud rate that the Armada SoCs can support. According to the hardware datasheet the maximum frequency supported by the Armada 370 SoC is tclk/4. But for the Armada XP, Armada 38x and Armada 39x SoCs the limitation is 50MHz and for the Armada 375 it is tclk/15.
Currently the armada-370-spi compatible is only used by the Armada 370 and the Armada XP device tree. On Armada 370, tclk cannot be higher than 200MHz. In order to be able to handle both SoCs, we can take the minimum of 50MHz and tclk/4.
A proper solution is adding a compatible string for each SoC, but it can't be done as a fix for compatibility reason (we can't modify device tree that have been already released) and it will be part of a separate patch.
--- drivers/spi/spi-orion.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-)
drivers/spi/spi-orion.c +23 -2
@@ -61,6 +61,12 @@ enum orion_spi_type {struct orion_spi_dev {enum orion_spi_type typ; +/* +* min_divisor and max_hz should be exclusive, the only we can +* have both is for managing the armada-370-spi case with old +* device tree +*/ +unsigned long max_hz;unsigned int min_divisor;unsigned int max_divisor;u32 prescale_mask;
@@ -387,8 +393,9 @@ static const struct orion_spi_dev orion_static const struct orion_spi_dev armada_spi_dev_data = { .typ =ARMADA_SPI , - .min_divisor =1 , + .min_divisor =4 , .max_divisor =1920 , + .max_hz =50000000 , .prescale_mask =ARMADA_SPI_CLK_PRESCALE_MASK , };
@@ -454,7 +461,21 @@ static int orion_spi_probe(struct platfo goto out; tclk_hz =clk_get_rate (spi->clk); - master->max_speed_hz =DIV_ROUND_UP (tclk_hz, devdata->min_divisor); + +/* +* With old device tree, armada-370-spi could be used with +* Armada XP, however for this SoC the maximum frequency is +* 50MHz instead of tclk/4. On Armada 370, tclk cannot be +* higher than 200MHz. So, in order to be able to handle both +* SoCs, we can take the minimum of 50MHz and tclk/4. +*/ +if (of_device_is_compatible (pdev->dev.of_node, +"marvell,armada-370-spi" )) + master->max_speed_hz =min (devdata->max_hz, +DIV_ROUND_UP (tclk_hz, devdata->min_divisor)); +else + master->max_speed_hz = +DIV_ROUND_UP (tclk_hz, devdata->min_divisor); master->min_speed_hz =DIV_ROUND_UP (tclk_hz, devdata->max_divisor); r =platform_get_resource (pdev,IORESOURCE_MEM ,0 );
Patches currently in stable-queue which might be from [email protected] are
queue-4.0/spi-orion-fix-maximum-baud-rates-for-armada-370-xp.patch