Re: [PATCH 1/2] clk: Add composite clock type

From: Prashant Gaikwad
Date: Fri Jan 04 2013 - 21:50:24 EST


On Saturday 05 January 2013 03:48 AM, Stephen Boyd wrote:
On 01/03/13 21:51, Prashant Gaikwad wrote:
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index f0b269a..baf7608 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -2,7 +2,8 @@
obj-$(CONFIG_HAVE_CLK) += clk-devres.o
obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o
obj-$(CONFIG_COMMON_CLK) += clk.o clk-fixed-rate.o clk-gate.o \
- clk-mux.o clk-divider.o clk-fixed-factor.o
+ clk-mux.o clk-divider.o clk-fixed-factor.o \
+ clk-composite.o
This list is getting a little out of hand. Should we sort it
alphabetically and put each file on one line?

Do you want me to do it in this patch?


# SoCs specific
obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o
obj-$(CONFIG_ARCH_NOMADIK) += clk-nomadik.o
diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
new file mode 100644
index 0000000..8634dbf
--- /dev/null
+++ b/drivers/clk/clk-composite.c
@@ -0,0 +1,208 @@
+/*
+ * 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/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+#define to_clk_composite(_hw) container_of(_hw, struct clk_composite, hw)
+
+static u8 clk_composite_get_parent(struct clk_hw *hw)
+{
+ struct clk_composite *composite = to_clk_composite(hw);
+ const struct clk_ops *mux_ops = composite->mux_ops;
+ struct clk_hw *mux_hw = composite->mux_hw;
+
+ mux_hw->clk = hw->clk;
Looks like this is already done down in the register function. Why are
we doing it again here and in each op?

Some ops gets called during clk_init which is before clk_register returns.


+
+ return mux_ops->get_parent(mux_hw);
+}
[snip]
+struct clk *clk_register_composite(struct device *dev, const char *name,
+ const char **parent_names, int num_parents,
+ struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
+ struct clk_hw *div_hw, const struct clk_ops *div_ops,
+ struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
+ unsigned long flags)
+{
+ struct clk *clk;
+ struct clk_init_data init;
+ struct clk_composite *composite;
+ struct clk_ops *clk_composite_ops;
+
+ composite = kzalloc(sizeof(struct clk_ops), GFP_KERNEL);
sizeof(*composite) != sizeof(struct clk_ops)

Thanks.

+ if (!composite) {
+ pr_err("%s: could not allocate composite clk\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ init.name = name;
+ init.flags = flags | CLK_IS_BASIC;
+ init.parent_names = parent_names;
+ init.num_parents = num_parents;
+
+ /* allocate the clock ops */
+ clk_composite_ops = kzalloc(sizeof(struct clk_ops), GFP_KERNEL);
This one looks right though. Perhaps you should change style to use
sizeof(*clk_composite_ops) so that the above mistake doesn't happen.

Sure.

+ if (!clk_composite_ops) {
+ pr_err("%s: could not allocate clk ops\n", __func__);
+ kfree(composite);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ if (mux_hw && mux_ops) {
+ if (!mux_ops->get_parent || !mux_ops->set_parent) {
+ clk = ERR_PTR(-EINVAL);
+ goto err;
+ }
+
+ composite->mux_hw = mux_hw;
+ composite->mux_ops = mux_ops;
+ clk_composite_ops->get_parent = clk_composite_get_parent;
+ clk_composite_ops->set_parent = clk_composite_set_parent;
+ }
+
+ if (div_hw && div_ops) {
+ if (!div_ops->recalc_rate || !div_ops->round_rate ||
+ !div_ops->set_rate) {
+ clk = ERR_PTR(-EINVAL);
+ goto err;
+ }
+
+ composite->div_hw = div_hw;
+ composite->div_ops = div_ops;
+ clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
+ clk_composite_ops->round_rate = clk_composite_round_rate;
+ clk_composite_ops->set_rate = clk_composite_set_rate;
+ }
+
+ if (gate_hw && gate_ops) {
+ if (!gate_ops->is_enabled || !gate_ops->enable ||
+ !gate_ops->disable) {
+ clk = ERR_PTR(-EINVAL);
+ goto err;
+ }
+
+ composite->gate_hw = gate_hw;
+ composite->gate_ops = gate_ops;
+ clk_composite_ops->is_enabled = clk_composite_is_enabled;
+ clk_composite_ops->enable = clk_composite_enable;
+ clk_composite_ops->disable = clk_composite_disable;
+ }
+
+ init.ops = clk_composite_ops;
+ composite->hw.init = &init;
+
+ clk = clk_register(NULL, &composite->hw);
Please pass dev here.

Yes.

+ if (IS_ERR(clk))
+ goto err;
+
+ if (composite->mux_hw)
+ composite->mux_hw->clk = clk;
+
+ if (composite->div_hw)
+ composite->div_hw->clk = clk;
+
+ if (composite->gate_hw)
+ composite->gate_hw->clk = clk;
+
+ return clk;
+
+err:
+ kfree(clk_composite_ops);
+ kfree(composite);
+ return clk;
+}


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