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authorAbel Vesa <abel.vesa@nxp.com>2018-12-01 13:52:14 +0300
committerStephen Boyd <sboyd@kernel.org>2018-12-03 21:12:50 +0300
commitd3ff9728134eeaa13d5bbb23c3f2e188f99cfdf9 (patch)
tree22eaa58af4a751afd934cf4a60e29b0cf489e2f5 /drivers/clk/imx/clk-composite-8m.c
parent1cf3817bf1f52e57b3f5eb0413ee0d7f0c2e9829 (diff)
downloadlinux-d3ff9728134eeaa13d5bbb23c3f2e188f99cfdf9.tar.xz
clk: imx: Add imx composite clock
Since a lot of clocks on imx8m are formed by a mux, gate, predivider and divider, the idea here is to combine all of those into one composite clock, but we need to deal with both predivider and divider at the same time and therefore we add the imx8m_clk_composite_divider_ops and register the composite clock with those. Signed-off-by: Abel Vesa <abel.vesa@nxp.com> Suggested-by: Sascha Hauer <s.hauer@pengutronix.de> Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers/clk/imx/clk-composite-8m.c')
-rw-r--r--drivers/clk/imx/clk-composite-8m.c178
1 files changed, 178 insertions, 0 deletions
diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c
new file mode 100644
index 000000000000..6d9d3714b4df
--- /dev/null
+++ b/drivers/clk/imx/clk-composite-8m.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018 NXP
+ */
+
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+
+#include "clk.h"
+
+#define PCG_PREDIV_SHIFT 16
+#define PCG_PREDIV_WIDTH 3
+#define PCG_PREDIV_MAX 8
+
+#define PCG_DIV_SHIFT 0
+#define PCG_DIV_WIDTH 6
+#define PCG_DIV_MAX 64
+
+#define PCG_PCS_SHIFT 24
+#define PCG_PCS_MASK 0x7
+
+#define PCG_CGC_SHIFT 28
+
+static unsigned long imx8m_clk_composite_divider_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ unsigned long prediv_rate;
+ unsigned int prediv_value;
+ unsigned int div_value;
+
+ prediv_value = readl(divider->reg) >> divider->shift;
+ prediv_value &= clk_div_mask(divider->width);
+
+ prediv_rate = divider_recalc_rate(hw, parent_rate, prediv_value,
+ NULL, divider->flags,
+ divider->width);
+
+ div_value = readl(divider->reg) >> PCG_DIV_SHIFT;
+ div_value &= clk_div_mask(PCG_DIV_WIDTH);
+
+ return divider_recalc_rate(hw, prediv_rate, div_value, NULL,
+ divider->flags, PCG_DIV_WIDTH);
+}
+
+static int imx8m_clk_composite_compute_dividers(unsigned long rate,
+ unsigned long parent_rate,
+ int *prediv, int *postdiv)
+{
+ int div1, div2;
+ int error = INT_MAX;
+ int ret = -EINVAL;
+
+ *prediv = 1;
+ *postdiv = 1;
+
+ for (div1 = 1; div1 <= PCG_PREDIV_MAX; div1++) {
+ for (div2 = 1; div2 <= PCG_DIV_MAX; div2++) {
+ int new_error = ((parent_rate / div1) / div2) - rate;
+
+ if (abs(new_error) < abs(error)) {
+ *prediv = div1;
+ *postdiv = div2;
+ error = new_error;
+ ret = 0;
+ }
+ }
+ }
+ return ret;
+}
+
+static long imx8m_clk_composite_divider_round_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long *prate)
+{
+ int prediv_value;
+ int div_value;
+
+ imx8m_clk_composite_compute_dividers(rate, *prate,
+ &prediv_value, &div_value);
+ rate = DIV_ROUND_UP(*prate, prediv_value);
+
+ return DIV_ROUND_UP(rate, div_value);
+
+}
+
+static int imx8m_clk_composite_divider_set_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_divider *divider = to_clk_divider(hw);
+ unsigned long flags = 0;
+ int prediv_value;
+ int div_value;
+ int ret = 0;
+ u32 val;
+
+ ret = imx8m_clk_composite_compute_dividers(rate, parent_rate,
+ &prediv_value, &div_value);
+ if (ret)
+ return -EINVAL;
+
+ spin_lock_irqsave(divider->lock, flags);
+
+ val = readl(divider->reg);
+ val &= ~((clk_div_mask(divider->width) << divider->shift) |
+ (clk_div_mask(PCG_DIV_WIDTH) << PCG_DIV_SHIFT));
+
+ val |= (u32)(prediv_value - 1) << divider->shift;
+ val |= (u32)(div_value - 1) << PCG_DIV_SHIFT;
+ writel(val, divider->reg);
+
+ spin_unlock_irqrestore(divider->lock, flags);
+
+ return ret;
+}
+
+static const struct clk_ops imx8m_clk_composite_divider_ops = {
+ .recalc_rate = imx8m_clk_composite_divider_recalc_rate,
+ .round_rate = imx8m_clk_composite_divider_round_rate,
+ .set_rate = imx8m_clk_composite_divider_set_rate,
+};
+
+struct clk *imx8m_clk_composite_flags(const char *name,
+ const char **parent_names,
+ int num_parents, void __iomem *reg,
+ unsigned long flags)
+{
+ struct clk_hw *hw = ERR_PTR(-ENOMEM), *mux_hw;
+ struct clk_hw *div_hw, *gate_hw;
+ struct clk_divider *div = NULL;
+ struct clk_gate *gate = NULL;
+ struct clk_mux *mux = NULL;
+
+ mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+ if (!mux)
+ goto fail;
+
+ mux_hw = &mux->hw;
+ mux->reg = reg;
+ mux->shift = PCG_PCS_SHIFT;
+ mux->mask = PCG_PCS_MASK;
+
+ div = kzalloc(sizeof(*div), GFP_KERNEL);
+ if (!div)
+ goto fail;
+
+ div_hw = &div->hw;
+ div->reg = reg;
+ div->shift = PCG_PREDIV_SHIFT;
+ div->width = PCG_PREDIV_WIDTH;
+ div->lock = &imx_ccm_lock;
+ div->flags = CLK_DIVIDER_ROUND_CLOSEST;
+
+ gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+ if (!gate)
+ goto fail;
+
+ gate_hw = &gate->hw;
+ gate->reg = reg;
+ gate->bit_idx = PCG_CGC_SHIFT;
+
+ hw = clk_hw_register_composite(NULL, name, parent_names, num_parents,
+ mux_hw, &clk_mux_ops, div_hw,
+ &imx8m_clk_composite_divider_ops,
+ gate_hw, &clk_gate_ops, flags);
+ if (IS_ERR(hw))
+ goto fail;
+
+ return hw->clk;
+
+fail:
+ kfree(gate);
+ kfree(div);
+ kfree(mux);
+ return ERR_CAST(hw);
+}