lkml.org 
[lkml]   [2017]   [Oct]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 4/5] clk: aspeed: Register gated clocks
Date
The majority of the clocks in the system are gates paired with a reset
controller that holds the IP in reset.

This borrows from clk_hw_register_gate, but registers two 'gates', one
to control the clock enable register and the other to control the reset
IP. This allows us to enforce the ordering:

1. Place IP in reset
2. Enable clock
3. Delay
4. Release reset

There are some gates that do not have an associated reset; these are
handled by using -1 as the index for the reset.

Signed-off-by: Joel Stanley <joel@jms.id.au>

---
v4:
- Drop useless 'disable clock' comment
- Drop CLK_IS_BASIC flag
- Fix 'there are a number of clocks...' comment
- Pass device to clk registration functions
- Check for errors when registering clk_hws
v3:
- Remove gates offset as gates are now at the start of the list
---
drivers/clk/clk-aspeed.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 130 insertions(+)

diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
index adb295292189..a424b056e767 100644
--- a/drivers/clk/clk-aspeed.c
+++ b/drivers/clk/clk-aspeed.c
@@ -228,6 +228,107 @@ static const struct aspeed_clk_soc_data ast2400_data = {
.calc_pll = aspeed_ast2400_calc_pll,
};

+static int aspeed_clk_enable(struct clk_hw *hw)
+{
+ struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
+ unsigned long flags;
+ u32 clk = BIT(gate->clock_idx);
+ u32 rst = BIT(gate->reset_idx);
+
+ spin_lock_irqsave(gate->lock, flags);
+
+ if (gate->reset_idx >= 0) {
+ /* Put IP in reset */
+ regmap_update_bits(gate->map, ASPEED_RESET_CTRL, rst, rst);
+
+ /* Delay 100us */
+ udelay(100);
+ }
+
+ /* Enable clock */
+ regmap_update_bits(gate->map, ASPEED_CLK_STOP_CTRL, clk, 0);
+
+ if (gate->reset_idx >= 0) {
+ /* Delay 10ms */
+ /* TODO: can we sleep here? */
+ msleep(10);
+
+ /* Take IP out of reset */
+ regmap_update_bits(gate->map, ASPEED_RESET_CTRL, rst, 0);
+ }
+
+ spin_unlock_irqrestore(gate->lock, flags);
+
+ return 0;
+}
+
+static void aspeed_clk_disable(struct clk_hw *hw)
+{
+ struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
+ unsigned long flags;
+ u32 clk = BIT(gate->clock_idx);
+
+ spin_lock_irqsave(gate->lock, flags);
+
+ regmap_update_bits(gate->map, ASPEED_CLK_STOP_CTRL, clk, clk);
+
+ spin_unlock_irqrestore(gate->lock, flags);
+}
+
+static int aspeed_clk_is_enabled(struct clk_hw *hw)
+{
+ struct aspeed_clk_gate *gate = to_aspeed_clk_gate(hw);
+ u32 clk = BIT(gate->clock_idx);
+ u32 reg;
+
+ regmap_read(gate->map, ASPEED_CLK_STOP_CTRL, &reg);
+
+ return (reg & clk) ? 0 : 1;
+}
+
+static const struct clk_ops aspeed_clk_gate_ops = {
+ .enable = aspeed_clk_enable,
+ .disable = aspeed_clk_disable,
+ .is_enabled = aspeed_clk_is_enabled,
+};
+
+static struct clk_hw *aspeed_clk_hw_register_gate(struct device *dev,
+ const char *name, const char *parent_name, unsigned long flags,
+ struct regmap *map, u8 clock_idx, u8 reset_idx,
+ u8 clk_gate_flags, spinlock_t *lock)
+{
+ struct aspeed_clk_gate *gate;
+ struct clk_init_data init;
+ struct clk_hw *hw;
+ int ret;
+
+ gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+ if (!gate)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &aspeed_clk_gate_ops;
+ init.flags = flags;
+ init.parent_names = parent_name ? &parent_name : NULL;
+ init.num_parents = parent_name ? 1 : 0;
+
+ gate->map = map;
+ gate->clock_idx = clock_idx;
+ gate->reset_idx = reset_idx;
+ gate->flags = clk_gate_flags;
+ gate->lock = lock;
+ gate->hw.init = &init;
+
+ hw = &gate->hw;
+ ret = clk_hw_register(dev, hw);
+ if (ret) {
+ kfree(gate);
+ hw = ERR_PTR(ret);
+ }
+
+ return hw;
+}
+
static int aspeed_clk_probe(struct platform_device *pdev)
{
const struct aspeed_clk_soc_data *soc_data;
@@ -235,6 +336,7 @@ static int aspeed_clk_probe(struct platform_device *pdev)
struct regmap *map;
struct clk_hw *hw;
u32 val, rate;
+ int i;

map = syscon_node_to_regmap(dev->of_node);
if (IS_ERR(map)) {
@@ -323,6 +425,34 @@ static int aspeed_clk_probe(struct platform_device *pdev)
return PTR_ERR(hw);
aspeed_clk_data->hws[ASPEED_CLK_BCLK] = hw;

+ /*
+ * TODO: There are a number of clocks that not included in this driver
+ * as more information is required:
+ * D2-PLL
+ * D-PLL
+ * YCLK
+ * RGMII
+ * RMII
+ * UART[1..5] clock source mux
+ */
+
+ for (i = 0; i < ARRAY_SIZE(aspeed_gates); i++) {
+ const struct aspeed_gate_data *gd = &aspeed_gates[i];
+
+ hw = aspeed_clk_hw_register_gate(dev,
+ gd->name,
+ gd->parent_name,
+ gd->flags,
+ map,
+ gd->clock_idx,
+ gd->reset_idx,
+ CLK_GATE_SET_TO_DISABLE,
+ &aspeed_clk_lock);
+ if (IS_ERR(hw))
+ return PTR_ERR(hw);
+ aspeed_clk_data->hws[i] = hw;
+ }
+
return 0;
};

--
2.14.1
\
 
 \ /
  Last update: 2017-10-03 08:57    [W:0.069 / U:2.160 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site