[PATCH v3 1/4] ARM: rockchip: rk3288: Switch to use the proper PWM IP

Doug Anderson dianders at chromium.org
Tue Aug 19 09:07:53 PDT 2014

The rk3288 SoC has an option to switch all of the PWMs in the system
between the old IP block and the new IP block.  The new IP block is
working and tested and the suggested PWM to use, so setup the SoC to
use it and then we can pretend that the other IP block doesn't exist.

This code could go lots of other places, but we've put it here.  Why?
- Pushing it to the bootloader just makes the code harder to update in
  the field.  If we later find a bug in the new IP block and want to
  change our mind about what to use we want it to be easy to update.
- Putting this code in the driver for IP block is a lot of extra work,
  device tree bindings, etc.  Now that the new IP block is validated
  it's likely no future SoCs will need this code.  Why pollute the PWM
  driver with this?  This is an rk3288 thing so it should be in rk3288
- There's a single bit that switches over PWMs, which makes it extra
  hard to put this under the PWM device tree nodes.

Signed-off-by: Doug Anderson <dianders at chromium.org>
Changes in v3: None
Changes in v2:
- Check for failed ioremap()

 arch/arm/mach-rockchip/rockchip.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm/mach-rockchip/rockchip.c b/arch/arm/mach-rockchip/rockchip.c
index 8ab9e0e..93c59f6 100644
--- a/arch/arm/mach-rockchip/rockchip.c
+++ b/arch/arm/mach-rockchip/rockchip.c
@@ -24,6 +24,29 @@
 #include <asm/hardware/cache-l2x0.h>
 #include "core.h"
+static void __init rk3288_init_machine(void)
+	void *grf = ioremap(0xff770000, 0x10000);
+	if (!grf) {
+		pr_warn("%s: Couldn't map GRF\n", __func__);
+		return;
+	}
+	/* Set pwm_sel to RK design PWM in GRF_SOC_CON2; affects all PWMs */
+	writel(0x00010001, grf + 0x24c);
+	iounmap(grf);
+static void __init rockchip_init_machine(void)
+	if (of_machine_is_compatible("rockchip,rk3288"))
+		rk3288_init_machine();
+	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 static const char * const rockchip_board_dt_compat[] = {
@@ -34,6 +57,7 @@ static const char * const rockchip_board_dt_compat[] = {
 DT_MACHINE_START(ROCKCHIP_DT, "Rockchip Cortex-A9 (Device Tree)")
+	.init_machine	= rockchip_init_machine,
 	.l2c_aux_val	= 0,
 	.l2c_aux_mask	= ~0,
 	.dt_compat	= rockchip_board_dt_compat,

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