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authorPrashant Gaikwad <pgaikwad@nvidia.com>2013-01-11 13:16:20 +0530
committerStephen Warren <swarren@nvidia.com>2013-01-28 11:19:07 -0700
commit8f8f484bf355e546c62c47b8a8c8d19b28787798 (patch)
treecd64be7c876f3bdc9bcf8d06d7c02304bbffc93e /drivers/clk/tegra/clk-divider.c
parent9598566721fe7524cca575975ea7e8ea2e27a71b (diff)
downloadlinux-stericsson-8f8f484bf355e546c62c47b8a8c8d19b28787798.tar.gz
clk: tegra: add Tegra specific clocks
Add Tegra specific clocks, pll, pll_out, peripheral, frac_divider, super. Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com> [swarren: alloc sizeof(*foo) not sizeof(struct foo), add comments re: storing pointers to stack variables, make a timeout loop more idiomatic, use _clk_pll_disable() not clk_disable_pll() from _program_pll() to avoid redundant lock operations, unified tegra_clk_periph() and tegra_clk_periph_nodiv(), unified tegra_clk_pll{,e}, rename all clock registration functions so they don't have the same name as the clock structs, return -EINVAL from clk_plle_enable when matching table rate not found, pass ops to _tegra_clk_register_pll rather than a bool.] Acked-by: Mike Turquette <mturquette@linaro.org> Signed-off-by: Stephen Warren <swarren@nvidia.com>
Diffstat (limited to 'drivers/clk/tegra/clk-divider.c')
-rw-r--r--drivers/clk/tegra/clk-divider.c187
1 files changed, 187 insertions, 0 deletions
diff --git a/drivers/clk/tegra/clk-divider.c b/drivers/clk/tegra/clk-divider.c
new file mode 100644
index 000000000000..4d75b1f37e3a
--- /dev/null
+++ b/drivers/clk/tegra/clk-divider.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+
+#include "clk.h"
+
+#define pll_out_override(p) (BIT((p->shift - 6)))
+#define div_mask(d) ((1 << (d->width)) - 1)
+#define get_mul(d) (1 << d->frac_width)
+#define get_max_div(d) div_mask(d)
+
+#define PERIPH_CLK_UART_DIV_ENB BIT(24)
+
+static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate,
+ unsigned long parent_rate)
+{
+ s64 divider_ux1 = parent_rate;
+ u8 flags = divider->flags;
+ int mul;
+
+ if (!rate)
+ return 0;
+
+ mul = get_mul(divider);
+
+ if (!(flags & TEGRA_DIVIDER_INT))
+ divider_ux1 *= mul;
+
+ if (flags & TEGRA_DIVIDER_ROUND_UP)
+ divider_ux1 += rate - 1;
+
+ do_div(divider_ux1, rate);
+
+ if (flags & TEGRA_DIVIDER_INT)
+ divider_ux1 *= mul;
+
+ divider_ux1 -= mul;
+
+ if (divider_ux1 < 0)
+ return 0;
+
+ if (divider_ux1 > get_max_div(divider))
+ return -EINVAL;
+
+ return divider_ux1;
+}
+
+static unsigned long clk_frac_div_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
+ u32 reg;
+ int div, mul;
+ u64 rate = parent_rate;
+
+ reg = readl_relaxed(divider->reg) >> divider->shift;
+ div = reg & div_mask(divider);
+
+ mul = get_mul(divider);
+ div += mul;
+
+ rate *= mul;
+ rate += div - 1;
+ do_div(rate, div);
+
+ return rate;
+}
+
+static long clk_frac_div_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
+ int div, mul;
+ unsigned long output_rate = *prate;
+
+ if (!rate)
+ return output_rate;
+
+ div = get_div(divider, rate, output_rate);
+ if (div < 0)
+ return *prate;
+
+ mul = get_mul(divider);
+
+ return DIV_ROUND_UP(output_rate * mul, div + mul);
+}
+
+static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
+ int div;
+ unsigned long flags = 0;
+ u32 val;
+
+ div = get_div(divider, rate, parent_rate);
+ if (div < 0)
+ return div;
+
+ if (divider->lock)
+ spin_lock_irqsave(divider->lock, flags);
+
+ val = readl_relaxed(divider->reg);
+ val &= ~(div_mask(divider) << divider->shift);
+ val |= div << divider->shift;
+
+ if (divider->flags & TEGRA_DIVIDER_UART) {
+ if (div)
+ val |= PERIPH_CLK_UART_DIV_ENB;
+ else
+ val &= ~PERIPH_CLK_UART_DIV_ENB;
+ }
+
+ if (divider->flags & TEGRA_DIVIDER_FIXED)
+ val |= pll_out_override(divider);
+
+ writel_relaxed(val, divider->reg);
+
+ if (divider->lock)
+ spin_unlock_irqrestore(divider->lock, flags);
+
+ return 0;
+}
+
+const struct clk_ops tegra_clk_frac_div_ops = {
+ .recalc_rate = clk_frac_div_recalc_rate,
+ .set_rate = clk_frac_div_set_rate,
+ .round_rate = clk_frac_div_round_rate,
+};
+
+struct clk *tegra_clk_register_divider(const char *name,
+ const char *parent_name, void __iomem *reg,
+ unsigned long flags, u8 clk_divider_flags, u8 shift, u8 width,
+ u8 frac_width, spinlock_t *lock)
+{
+ struct tegra_clk_frac_div *divider;
+ struct clk *clk;
+ struct clk_init_data init;
+
+ divider = kzalloc(sizeof(*divider), GFP_KERNEL);
+ if (!divider) {
+ pr_err("%s: could not allocate fractional divider clk\n",
+ __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ init.name = name;
+ init.ops = &tegra_clk_frac_div_ops;
+ init.flags = flags;
+ init.parent_names = parent_name ? &parent_name : NULL;
+ init.num_parents = parent_name ? 1 : 0;
+
+ divider->reg = reg;
+ divider->shift = shift;
+ divider->width = width;
+ divider->frac_width = frac_width;
+ divider->lock = lock;
+ divider->flags = clk_divider_flags;
+
+ /* Data in .init is copied by clk_register(), so stack variable OK */
+ divider->hw.init = &init;
+
+ clk = clk_register(NULL, &divider->hw);
+ if (IS_ERR(clk))
+ kfree(divider);
+
+ return clk;
+}