The patch adds support for dynamic reconfiguration of clock output rate.
Output clocks are registered as dividers and set rate callback function
is used for dynamic reconfiguration.
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.da...@xilinx.com>
Co-developed-by: Chirag Parekh <chirag.par...@xilinx.com>
---
v6:
Remove the typecast.
use min for capping frequency.
use polled timeout
v7:
Use devm functions
Add the spinlock
v10:
Add a codeveloped by tag.
.../clocking-wizard/clk-xlnx-clock-wizard.c | 178 ++++++++++++++++++++-
1 file changed, 173 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
b/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
index e08fc2f..b1bfdb86 100644
--- a/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
+++ b/drivers/staging/clocking-wizard/clk-xlnx-clock-wizard.c
@@ -15,6 +15,7 @@
#include <linux/of.h>
#include <linux/module.h>
#include <linux/err.h>
+#include <linux/iopoll.h>
#define WZRD_NUM_OUTPUTS 7
#define WZRD_ACLK_MAX_FREQ 250000000UL
@@ -29,8 +30,24 @@
#define WZRD_DIVCLK_DIVIDE_SHIFT 0
#define WZRD_DIVCLK_DIVIDE_MASK (0xff <<
WZRD_DIVCLK_DIVIDE_SHIFT)
#define WZRD_CLKOUT_DIVIDE_SHIFT 0
+#define WZRD_CLKOUT_DIVIDE_WIDTH 8
#define WZRD_CLKOUT_DIVIDE_MASK (0xff <<
WZRD_DIVCLK_DIVIDE_SHIFT)
+#define WZRD_DR_MAX_INT_DIV_VALUE 255
+#define WZRD_DR_STATUS_REG_OFFSET 0x04
+#define WZRD_DR_LOCK_BIT_MASK 0x00000001
+#define WZRD_DR_INIT_REG_OFFSET 0x25C
+#define WZRD_DR_DIV_TO_PHASE_OFFSET 4
+#define WZRD_DR_BEGIN_DYNA_RECONF 0x03
+
+#define WZRD_USEC_POLL 10
+#define WZRD_TIMEOUT_POLL 1000
+/* Get the mask from width */
+#define div_mask(width) ((1 << (width)) - 1)
+
+/* Extract divider instance from clock hardware instance */
+#define to_clk_wzrd_divider(_hw) container_of(_hw, struct clk_wzrd_divider, hw)
+
enum clk_wzrd_int_clks {
wzrd_clk_mul,
wzrd_clk_mul_div,
@@ -62,6 +79,29 @@ struct clk_wzrd {
bool suspended;
};
+/**
+ * struct clk_wzrd_divider - clock divider specific to clk_wzrd
+ *
+ * @hw: handle between common and hardware-specific interfaces
+ * @base: base address of register containing the divider
+ * @offset: offset address of register containing the divider
+ * @shift: shift to the divider bit field
+ * @width: width of the divider bit field
+ * @flags: clk_wzrd divider flags
+ * @table: array of value/divider pairs, last entry should have div = 0
+ * @lock: register lock
+ */
+struct clk_wzrd_divider {
+ struct clk_hw hw;
+ void __iomem *base;
+ u16 offset;
+ u8 shift;
+ u8 width;
+ u8 flags;
+ const struct clk_div_table *table;
+ spinlock_t *lock; /* divider lock */
+};
+
#define to_clk_wzrd(_nb) container_of(_nb, struct clk_wzrd, nb)
/* maximum frequencies for input/output clocks per speed grade */
@@ -71,6 +111,131 @@ static const unsigned long clk_wzrd_max_freq[] = {
1066000000UL
};
+/* spin lock variable for clk_wzrd */
+static DEFINE_SPINLOCK(clkwzrd_lock);
+
+static unsigned long clk_wzrd_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
+ void __iomem *div_addr = divider->base + divider->offset;
+ unsigned int val;
+
+ val = readl(div_addr) >> divider->shift;
+ val &= div_mask(divider->width);
+
+ return divider_recalc_rate(hw, parent_rate, val, divider->table,
+ divider->flags, divider->width);
+}
+
+static int clk_wzrd_dynamic_reconfig(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ int err;
+ u32 value;
+ unsigned long flags = 0;
+ struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
+ void __iomem *div_addr = divider->base + divider->offset;
+
+ if (divider->lock)
+ spin_lock_irqsave(divider->lock, flags);
+ else
+ __acquire(divider->lock);
+
+ value = DIV_ROUND_CLOSEST(parent_rate, rate);
+
+ /* Cap the value to max */
+ min_t(u32, value, WZRD_DR_MAX_INT_DIV_VALUE);
+
+ /* Set divisor and clear phase offset */
+ writel(value, div_addr);
+ writel(0x00, div_addr + WZRD_DR_DIV_TO_PHASE_OFFSET);
+
+ /* Check status register */
+ err = readl_poll_timeout(divider->base + WZRD_DR_STATUS_REG_OFFSET,
+ value, value & WZRD_DR_LOCK_BIT_MASK,
+ WZRD_USEC_POLL, WZRD_TIMEOUT_POLL);
+ if (err)
+ goto err_reconfig;
+
+ /* Initiate reconfiguration */
+ writel(WZRD_DR_BEGIN_DYNA_RECONF,
+ divider->base + WZRD_DR_INIT_REG_OFFSET);
+
+ /* Check status register */
+ err = readl_poll_timeout(divider->base + WZRD_DR_STATUS_REG_OFFSET,
+ value, value & WZRD_DR_LOCK_BIT_MASK,
+ WZRD_USEC_POLL, WZRD_TIMEOUT_POLL);
+err_reconfig:
+ if (divider->lock)
+ spin_unlock_irqrestore(divider->lock, flags);
+ else
+ __release(divider->lock);
+ return err;
+}
+
+static long clk_wzrd_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ u8 div;
+
+ /*
+ * since we don't change parent rate we just round rate to closest
+ * achievable
+ */
+ div = DIV_ROUND_CLOSEST(*prate, rate);
+
+ return *prate / div;
+}
+
+static const struct clk_ops clk_wzrd_clk_divider_ops = {
+ .round_rate = clk_wzrd_round_rate,
+ .set_rate = clk_wzrd_dynamic_reconfig,
+ .recalc_rate = clk_wzrd_recalc_rate,
+};
+
+static struct clk *clk_wzrd_register_divider(struct device *dev,
+ const char *name,
+ const char *parent_name,
+ unsigned long flags,
+ void __iomem *base, u16 offset,
+ u8 shift, u8 width,
+ u8 clk_divider_flags,
+ const struct clk_div_table *table,
+ spinlock_t *lock)
+{
+ struct clk_wzrd_divider *div;
+ struct clk_hw *hw;
+ struct clk_init_data init;
+ int ret;
+
+ div = devm_kzalloc(dev, sizeof(*div), GFP_KERNEL);
+ if (!div)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &clk_wzrd_clk_divider_ops;
+ init.flags = flags;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+
+ div->base = base;
+ div->offset = offset;
+ div->shift = shift;
+ div->width = width;
+ div->flags = clk_divider_flags;
+ div->lock = lock;
+ div->hw.init = &init;
+ div->table = table;
+
+ hw = &div->hw;
+ ret = devm_clk_hw_register(dev, hw);
+ if (ret)
+ hw = ERR_PTR(ret);
+
+ return hw->clk;
+}
+
static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long
event,
void *data)
{
@@ -251,11 +416,14 @@ static int clk_wzrd_probe(struct platform_device *pdev)
ret = -EINVAL;
goto err_rm_int_clks;
}
- reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2) + i * 12);
- reg &= WZRD_CLKOUT_DIVIDE_MASK;
- reg >>= WZRD_CLKOUT_DIVIDE_SHIFT;
- clk_wzrd->clkout[i] = clk_register_fixed_factor
- (&pdev->dev, clkout_name, clk_name, 0, 1, reg);
+ clk_wzrd->clkout[i] = clk_wzrd_register_divider(&pdev->dev,
+ clkout_name,
+ clk_name, 0,
+ clk_wzrd->base, (WZRD_CLK_CFG_REG(2) + i * 12),
+ WZRD_CLKOUT_DIVIDE_SHIFT,
+ WZRD_CLKOUT_DIVIDE_WIDTH,
+ CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ALLOW_ZERO,
+ NULL, &clkwzrd_lock);
if (IS_ERR(clk_wzrd->clkout[i])) {
int j;
--
2.1.1
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