lkml.org 
[lkml]   [2019]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 05/10] clk: clock-wizard: Add support for fractional support
Date
From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

Currently the set rate granularity is to integral divisors.
Add support for the fractional divisors.
Only the first output0 is fractional in the hardware.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
---
drivers/clk/clk-xlnx-clock-wizard.c | 192 +++++++++++++++++++++++++++++++++---
1 file changed, 179 insertions(+), 13 deletions(-)

diff --git a/drivers/clk/clk-xlnx-clock-wizard.c b/drivers/clk/clk-xlnx-clock-wizard.c
index 870e7fb..bc0354a 100644
--- a/drivers/clk/clk-xlnx-clock-wizard.c
+++ b/drivers/clk/clk-xlnx-clock-wizard.c
@@ -26,11 +26,15 @@

#define WZRD_CLKFBOUT_MULT_SHIFT 8
#define WZRD_CLKFBOUT_MULT_MASK (0xff << WZRD_CLKFBOUT_MULT_SHIFT)
+#define WZRD_CLKFBOUT_FRAC_SHIFT 16
+#define WZRD_CLKFBOUT_FRAC_MASK (0x3ff << WZRD_CLKFBOUT_FRAC_SHIFT)
#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_CLKOUT_FRAC_SHIFT 8
+#define WZRD_CLKOUT_FRAC_MASK 0x3ff

#define WZRD_DR_MAX_INT_DIV_VALUE 255
#define WZRD_DR_NUM_RETRIES 10000
@@ -49,6 +53,7 @@
enum clk_wzrd_int_clks {
wzrd_clk_mul,
wzrd_clk_mul_div,
+ wzrd_clk_mul_frac,
wzrd_clk_int_max
};

@@ -124,7 +129,7 @@ static unsigned long clk_wzrd_recalc_rate(struct clk_hw *hw,
val &= div_mask(divider->width);

return divider_recalc_rate(hw, parent_rate, val, divider->table,
- divider->flags, divider->width);
+ divider->flags);
}

static int clk_wzrd_dynamic_reconfig(struct clk_hw *hw, unsigned long rate,
@@ -210,6 +215,161 @@ static const struct clk_ops clk_wzrd_clk_divider_ops = {
.recalc_rate = clk_wzrd_recalc_rate,
};

+static unsigned long clk_wzrd_recalc_ratef(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ unsigned int val;
+ u32 div, frac;
+ struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
+ void __iomem *div_addr =
+ (void __iomem *)((u64)divider->base + divider->offset);
+
+ val = readl(div_addr);
+ div = val & div_mask(divider->width);
+ frac = (val >> WZRD_CLKOUT_FRAC_SHIFT) & WZRD_CLKOUT_FRAC_MASK;
+
+ return ((parent_rate * 1000) / ((div * 1000) + frac));
+}
+
+static int clk_wzrd_dynamic_reconfig_f(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ int err = 0;
+ u16 retries;
+ u32 value, pre;
+ unsigned long flags = 0;
+ unsigned long rate_div, f, clockout0_div;
+ struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
+ void __iomem *div_addr =
+ (void __iomem *)((u64)divider->base + divider->offset);
+
+ if (divider->lock)
+ spin_lock_irqsave(divider->lock, flags);
+ else
+ __acquire(divider->lock);
+
+ rate_div = ((parent_rate * 1000) / rate);
+ clockout0_div = rate_div / 1000;
+
+ pre = DIV_ROUND_CLOSEST((parent_rate * 1000), rate);
+ f = (u32)(pre - (clockout0_div * 1000));
+ f = f & WZRD_CLKOUT_FRAC_MASK;
+
+ value = ((f << WZRD_CLKOUT_DIVIDE_WIDTH) | (clockout0_div &
+ WZRD_CLKOUT_DIVIDE_MASK));
+
+ /* Set divisor and clear phase offset */
+ writel(value, div_addr);
+ writel(0x0, div_addr + WZRD_DR_DIV_TO_PHASE_OFFSET);
+
+ /* Check status register */
+ retries = WZRD_DR_NUM_RETRIES;
+ while (retries--) {
+ if (readl(divider->base + WZRD_DR_STATUS_REG_OFFSET) &
+ WZRD_DR_LOCK_BIT_MASK)
+ break;
+ }
+
+ if (!retries) {
+ err = -ETIMEDOUT;
+ goto err_reconfig;
+ }
+
+ /* Initiate reconfiguration */
+ writel(WZRD_DR_BEGIN_DYNA_RECONF,
+ divider->base + WZRD_DR_INIT_REG_OFFSET);
+
+ /* Check status register */
+ retries = WZRD_DR_NUM_RETRIES;
+ while (retries--) {
+ if (readl(divider->base + WZRD_DR_STATUS_REG_OFFSET) &
+ WZRD_DR_LOCK_BIT_MASK)
+ break;
+ }
+
+ if (!retries)
+ err = -ETIMEDOUT;
+
+err_reconfig:
+ if (divider->lock)
+ spin_unlock_irqrestore(divider->lock, flags);
+ else
+ __release(divider->lock);
+
+ return err;
+}
+
+static long clk_wzrd_round_rate_f(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ return rate;
+}
+
+static const struct clk_ops clk_wzrd_clk_divider_ops_f = {
+ .round_rate = clk_wzrd_round_rate_f,
+ .set_rate = clk_wzrd_dynamic_reconfig_f,
+ .recalc_rate = clk_wzrd_recalc_ratef,
+};
+
+static struct clk *clk_wzrd_register_divf(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;
+
+ if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
+ if (width + shift > 16) {
+ pr_warn("divider value exceeds LOWORD field\n");
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
+ /* allocate the divider */
+ div = kzalloc(sizeof(*div), GFP_KERNEL);
+ if (!div)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+
+ if (clk_divider_flags & CLK_DIVIDER_READ_ONLY)
+ init.ops = &clk_divider_ro_ops;
+ else
+ init.ops = &clk_wzrd_clk_divider_ops_f;
+
+ init.flags = flags | CLK_IS_BASIC;
+ init.parent_names = (parent_name ? &parent_name : NULL);
+ init.num_parents = (parent_name ? 1 : 0);
+
+ /* struct clk_divider assignments */
+ 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;
+
+ /* register the clock */
+ hw = &div->hw;
+ ret = clk_hw_register(dev, hw);
+ if (ret) {
+ kfree(div);
+ return ERR_PTR(ret);
+ }
+
+ return hw->clk;
+}
+
static struct clk *clk_wzrd_register_divider(struct device *dev,
const char *name,
const char *parent_name,
@@ -328,7 +488,7 @@ static SIMPLE_DEV_PM_OPS(clk_wzrd_dev_pm_ops, clk_wzrd_suspend,
static int clk_wzrd_probe(struct platform_device *pdev)
{
int i, ret;
- u32 reg;
+ u32 reg, reg_f, mult;
unsigned long rate;
const char *clk_name;
struct clk_wzrd *clk_wzrd;
@@ -380,17 +540,13 @@ static int clk_wzrd_probe(struct platform_device *pdev)
goto err_disable_clk;
}

- /* we don't support fractional div/mul yet */
- reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
- WZRD_CLKFBOUT_FRAC_EN;
- reg |= readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2)) &
- WZRD_CLKOUT0_FRAC_EN;
- if (reg)
- dev_warn(&pdev->dev, "fractional div/mul not supported\n");
-
/* register multiplier */
reg = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
WZRD_CLKFBOUT_MULT_MASK) >> WZRD_CLKFBOUT_MULT_SHIFT;
+ reg_f = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
+ WZRD_CLKFBOUT_FRAC_MASK) >> WZRD_CLKFBOUT_FRAC_SHIFT;
+
+ mult = ((reg * 1000) + reg_f);
clk_name = kasprintf(GFP_KERNEL, "%s_mul", dev_name(&pdev->dev));
if (!clk_name) {
ret = -ENOMEM;
@@ -399,7 +555,7 @@ static int clk_wzrd_probe(struct platform_device *pdev)
clk_wzrd->clks_internal[wzrd_clk_mul] = clk_register_fixed_factor
(&pdev->dev, clk_name,
__clk_get_name(clk_wzrd->clk_in1),
- 0, reg, 1);
+ 0, mult, 1000);
kfree(clk_name);
if (IS_ERR(clk_wzrd->clks_internal[wzrd_clk_mul])) {
dev_err(&pdev->dev, "unable to register fixed-factor clock\n");
@@ -437,8 +593,18 @@ static int clk_wzrd_probe(struct platform_device *pdev)
ret = -EINVAL;
goto err_rm_int_clks;
}
- clk_wzrd->clkout[i] = clk_wzrd_register_divider(&pdev->dev,
- clkout_name,
+ if (!i)
+ clk_wzrd->clkout[i] = clk_wzrd_register_divf
+ (&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);
+ else
+ 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,
--
2.1.1
\
 
 \ /
  Last update: 2019-11-28 07:38    [W:0.136 / U:1.960 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site