Re: [RESEND/PATCH v6 2/3] clk: qcom: Add regmap mux-div clocks support

From: Georgi Djakov
Date: Fri Oct 28 2016 - 12:54:10 EST


On 10/28/2016 04:59 AM, Stephen Boyd wrote:
On 10/19, Georgi Djakov wrote:
diff --git a/drivers/clk/qcom/clk-regmap-mux-div.c b/drivers/clk/qcom/clk-regmap-mux-div.c
new file mode 100644
index 000000000000..ec87f496606a
--- /dev/null
+++ b/drivers/clk/qcom/clk-regmap-mux-div.c
@@ -0,0 +1,254 @@
+/*
+ * Copyright (c) 2015, Linaro Limited
+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/export.h>

Are symbols exported. They probably should be for modules.

In the next patch i am using __clk_lookup(), which is not exported, so i made this builtin too. Will remove <export.h> from here.


+#include <linux/kernel.h>
+#include <linux/regmap.h>
+
+#include "clk-regmap-mux-div.h"
+
+#define CMD_RCGR 0x0
+#define CMD_RCGR_UPDATE BIT(0)
+#define CMD_RCGR_DIRTY_CFG BIT(4)
+#define CMD_RCGR_ROOT_OFF BIT(31)
+#define CFG_RCGR 0x4
+
+#define to_clk_regmap_mux_div(_hw) \
+ container_of(to_clk_regmap(_hw), struct clk_regmap_mux_div, clkr)
+
+int __mux_div_set_src_div(struct clk_regmap_mux_div *md, u32 src, u32 div)
+{
+ int ret, count;
+ u32 val, mask;
+ const char *name = clk_hw_get_name(&md->clkr.hw);
+
+ val = (div << md->hid_shift) | (src << md->src_shift);
+ mask = ((BIT(md->hid_width) - 1) << md->hid_shift) |
+ ((BIT(md->src_width) - 1) << md->src_shift);
+
+ ret = regmap_update_bits(md->clkr.regmap, CFG_RCGR + md->reg_offset,
+ mask, val);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(md->clkr.regmap, CMD_RCGR + md->reg_offset,
+ CMD_RCGR_UPDATE, CMD_RCGR_UPDATE);
+ if (ret)
+ return ret;
+
+ /* Wait for update to take effect */
+ for (count = 500; count > 0; count--) {
+ ret = regmap_read(md->clkr.regmap, CMD_RCGR + md->reg_offset,
+ &val);
+ if (ret)
+ return ret;
+ if (!(val & CMD_RCGR_UPDATE))
+ return 0;
+ udelay(1);
+ }
+
+ pr_err("%s: RCG did not update its configuration", name);
+ return -EBUSY;
+}
+
+static void __mux_div_get_src_div(struct clk_regmap_mux_div *md, u32 *src,
+ u32 *div)
+{
+ u32 val, __div, __src;

Perhaps just use d and s.


Ok.

+ const char *name = clk_hw_get_name(&md->clkr.hw);
+
+ regmap_read(md->clkr.regmap, CMD_RCGR + md->reg_offset, &val);
+
+ if (val & CMD_RCGR_DIRTY_CFG) {
+ pr_err("%s: RCG configuration is pending\n", name);
+ return;
+ }
+
+ regmap_read(md->clkr.regmap, CFG_RCGR + md->reg_offset, &val);
+ __src = (val >> md->src_shift);
+ __src &= BIT(md->src_width) - 1;
+ *src = __src;
+
+ __div = (val >> md->hid_shift);
+ __div &= BIT(md->hid_width) - 1;
+ *div = __div;
+}
+
+static unsigned long mux_div_recalc_rate(struct clk_hw *hw, unsigned long prate)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+ u32 div, src;
+ int i, num_parents = clk_hw_get_num_parents(hw);
+ const char *name = clk_hw_get_name(hw);
+
+ __mux_div_get_src_div(md, &src, &div);
+ for (i = 0; i < num_parents; i++)
+ if (src == md->parent_map[i].cfg) {
+ struct clk_hw *p = clk_hw_get_parent_by_index(hw, i);
+ unsigned long parent_rate = clk_hw_get_rate(p);
+
+ return mult_frac(parent_rate, 2, div + 1);
+ }
+
+ pr_err("%s: Can't find parent %d\n", name, src);
+ return 0;
+}
+
+static void mux_div_disable(struct clk_hw *hw)
+{
+ struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
+
+ __mux_div_set_src_div(md, md->safe_src, md->safe_div);

Ah this is to do magic tricks with cpuidle. In the android tree
they call clk_disable() on the CPU clks from the idle path and
that switches us over to the safe source and turns off the A53
PLL while the CPU is not powered. That's all sort of sneaky and
we're not doing that yet here so let's leave that until later.
Please remove the enable/disable stuff.


Ok, agree! Its not used currently. Removed.