OMAP3630 dpll3_m3_ck, dpll4_m2_ck, dpll4_m3_ck, dpll4_m4_ck,
dpll4_m5_ck & dpll4_m6_ck dividers gets loaded with reset
value after their respective PWRDN bits are set. Any dummy write
(Any other value different from the Read value) to the
corresponding CM_CLKSEL register will refresh the dividers.
Signed-off-by: Tero Kristo <t-kri...@ti.com>
---
.../devicetree/bindings/clock/ti/gate.txt | 1 +
drivers/clk/ti/gate.c | 58 +++++++++++++++++++-
2 files changed, 58 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/clock/ti/gate.txt
b/Documentation/devicetree/bindings/clock/ti/gate.txt
index 620a73d..9cebccb 100644
--- a/Documentation/devicetree/bindings/clock/ti/gate.txt
+++ b/Documentation/devicetree/bindings/clock/ti/gate.txt
@@ -21,6 +21,7 @@ Optional properties:
- ti,dss-clk : use DSS hardware OPS for the clock
- ti,am35xx-clk : use AM35xx hardware OPS for the clock
- ti,clkdm-name : clockdomain to control this gate
+- ti,hsdiv-restore : restore parent clock HSDIV value with enable
Examples:
trace_clk_div_ck: trace_clk_div_ck {
diff --git a/drivers/clk/ti/gate.c b/drivers/clk/ti/gate.c
index 2c68310..f15fbec 100644
--- a/drivers/clk/ti/gate.c
+++ b/drivers/clk/ti/gate.c
@@ -17,10 +17,15 @@
#include <linux/clk-provider.h>
#include <linux/slab.h>
+#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clk/ti.h>
+#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
+
+static int omap36xx_gate_clk_enable_with_hsdiv_restore(struct clk_hw *clk);
+
static const struct clk_ops omap_gate_clkdm_clk_ops = {
.init = &omap2_init_clk_clkdm,
.enable = &omap2_clkops_enable_clkdm,
@@ -34,6 +39,54 @@ static const struct clk_ops omap_gate_clk_ops = {
.is_enabled = &omap2_dflt_clk_is_enabled,
};
+static const struct clk_ops omap_gate_clk_hsdiv_restore_ops = {
+ .init = &omap2_init_clk_clkdm,
+ .enable = &omap36xx_gate_clk_enable_with_hsdiv_restore,
+ .disable = &omap2_dflt_clk_disable,
+ .is_enabled = &omap2_dflt_clk_is_enabled,
+};
+
+/**
+ * omap36xx_gate_clk_enable_with_hsdiv_restore - enable clocks suffering
+ * from HSDivider PWRDN problem Implements Errata ID: i556.
+ * @clk: DPLL output struct clk
+ *
+ * 3630 only: dpll3_m3_ck, dpll4_m2_ck, dpll4_m3_ck, dpll4_m4_ck,
+ * dpll4_m5_ck & dpll4_m6_ck dividers gets loaded with reset
+ * valueafter their respective PWRDN bits are set. Any dummy write
+ * (Any other value different from the Read value) to the
+ * corresponding CM_CLKSEL register will refresh the dividers.
+ */
+static int omap36xx_gate_clk_enable_with_hsdiv_restore(struct clk_hw *clk)
+{
+ struct clk_divider *parent;
+ struct clk_hw *parent_hw;
+ u32 dummy_v, orig_v;
+ int ret;
+
+ /* Clear PWRDN bit of HSDIVIDER */
+ ret = omap2_dflt_clk_enable(clk);
+
+ /* Parent is the x2 node, get parent of parent for the m2 div */
+ parent_hw = __clk_get_hw(__clk_get_parent(__clk_get_parent(clk->clk)));
+ parent = to_clk_divider(parent_hw);
+
+ /* Restore the dividers */
+ if (!ret) {
+ orig_v = __raw_readl(parent->reg);
+ dummy_v = orig_v;
+
+ /* Write any other value different from the Read value */
+ dummy_v ^= (1 << parent->shift);
+ __raw_writel(dummy_v, parent->reg);
+
+ /* Write the original divider */
+ __raw_writel(orig_v, parent->reg);
+ }
+
+ return ret;
+}
+
void __init of_omap_gate_clk_setup(struct device_node *node)
{
struct clk *clk;
@@ -63,7 +116,10 @@ void __init of_omap_gate_clk_setup(struct device_node *node)
/* No register, clkdm control only */
init.ops = &omap_gate_clkdm_clk_ops;
} else {
- init.ops = &omap_gate_clk_ops;
+ if (of_property_read_bool(node, "ti,hsdiv-restore"))
+ init.ops = &omap_gate_clk_hsdiv_restore_ops;
+ else
+ init.ops = &omap_gate_clk_ops;
clk_hw->enable_reg = of_iomap(node, 0);
of_property_read_u32(node, "ti,enable-bit", &val);
clk_hw->enable_bit = val;
--
1.7.9.5
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