Re: [PATCH V2] clk: qcom: Add spmi_pmic clock divider support
From: Tirupathi Reddy T
Date: Wed Sep 06 2017 - 08:00:40 EST
On 9/2/2017 1:56 AM, Stephen Boyd wrote:
On 08/31, Tirupathi Reddy wrote:
diff --git a/Documentation/devicetree/bindings/clock/clk-spmi-pmic-div.txt b/Documentation/devicetree/bindings/clock/clk-spmi-pmic-div.txt
new file mode 100644
index 0000000..48cb2f7
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/clk-spmi-pmic-div.txt
@@ -0,0 +1,49 @@
+Qualcomm Technologies, Inc. SPMI PMIC clock divider (clkdiv)
+
+clkdiv configures the clock frequency of a set of outputs on the PMIC.
+These clocks are typically wired through alternate functions on
+gpio pins.
+
+=======================
+Supported Properties
Just "Properties".
address in next patch set.
+=======================
+
+- compatible
+ Usage: required
+ Value type: <string>
+ Definition: should be "qcom,spmi-pmic-clkdiv".
+
+- reg
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: Addresses and sizes for the memory of this CLKDIV
+ peripheral.
+
+- clocks:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: reference to the xo clock.
+
+- clock-names:
+ Usage: required
+ Value type: <stringlist>
+ Definition: must be "xo".
+
+=======
+Example
+=======
+
+pm8998_clk_divs: qcom,clkdiv@0 {
@5b00
address in next patch set.
+ compatible = "qcom,spmi-pmic-clkdiv";
+ reg = <0x5b00 0x300>;
Drop the size
address in next patch set.
+ #clock-cells = <1>;
+ clocks = <&xo_board>;
+ clock-names = "xo";
+
+ assigned-clocks = <&pm8998_clk_divs CLKDIV1>,
+ <&pm8998_clk_divs CLKDIV2>,
+ <&pm8998_clk_divs CLKDIV3>;
+ assigned-clock-rates = <9600000>,
+ <9600000>,
+ <9600000>;
Not sure we need this part in the example, but OK.
+};
diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index 9f6c278..af5e489 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -196,3 +196,12 @@ config MSM_MMCC_8996
Support for the multimedia clock controller on msm8996 devices.
Say Y if you want to support multimedia devices such as display,
graphics, video encode/decode, camera, etc.
+
+config CLOCK_SPMI_PMIC_DIV
config SPMI_PMIC_CLKDIV?
address in next patch set.
+ tristate "spmi pmic clkdiv driver"
+ depends on (COMMON_CLK_QCOM && SPMI) || COMPILE_TEST
+ help
+ This driver supports the clkdiv functionality on the Qualcomm
+ Technologies, Inc. SPMI PMIC. It configures the frequency of
+ clkdiv outputs on the PMIC. These clocks are typically wired
+ through alternate functions on gpio pins.
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index 3f3aff2..ee8c91c 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -15,6 +15,7 @@ clk-qcom-$(CONFIG_QCOM_GDSC) += gdsc.o
# Keep alphabetically sorted by config
obj-$(CONFIG_APQ_GCC_8084) += gcc-apq8084.o
obj-$(CONFIG_APQ_MMCC_8084) += mmcc-apq8084.o
+obj-$(CONFIG_CLOCK_SPMI_PMIC_DIV) += clk-spmi-pmic-div.o
obj-$(CONFIG_IPQ_GCC_4019) += gcc-ipq4019.o
obj-$(CONFIG_IPQ_GCC_806X) += gcc-ipq806x.o
obj-$(CONFIG_IPQ_GCC_8074) += gcc-ipq8074.o
diff --git a/drivers/clk/qcom/clk-spmi-pmic-div.c b/drivers/clk/qcom/clk-spmi-pmic-div.c
new file mode 100644
index 0000000..24461fb
--- /dev/null
+++ b/drivers/clk/qcom/clk-spmi-pmic-div.c
@@ -0,0 +1,327 @@
+/* Copyright (c) 2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
Needed?
remove it in next patch set.
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <dt-bindings/clock/spmi_pmic_clk_div.h>
+
+#define REG_DIV_CTL1 0x43
+#define DIV_CTL1_DIV_FACTOR_MASK GENMASK(2, 0)
+
+#define REG_EN_CTL 0x46
+#define REG_EN_MASK BIT(7)
+#define REG_EN_SET BIT(7)
Why do we need this define? Just test if the mask comes out to be
non-zero instead.
okay. address in next patch set.
+
+#define ENABLE_DELAY_NS(cxo_ns, div) ((2 + 3 * div) * cxo_ns)
+#define DISABLE_DELAY_NS(cxo_ns, div) ((3 * div) * cxo_ns)
+
+#define CLK_SPMI_PMIC_DIV_OFFSET 1
+
+#define CLKDIV_XO_DIV_1_0 0
+#define CLKDIV_XO_DIV_1 1
+#define CLKDIV_XO_DIV_2 2
+#define CLKDIV_XO_DIV_4 3
+#define CLKDIV_XO_DIV_8 4
+#define CLKDIV_XO_DIV_16 5
+#define CLKDIV_XO_DIV_32 6
+#define CLKDIV_XO_DIV_64 7
+#define CLKDIV_MAX_ALLOWED 8
+
+struct clkdiv {
+ struct regmap *regmap;
+ u16 base;
+
+ /* clock properties */
+ struct clk_hw hw;
+ unsigned int div_factor;
+ unsigned int cxo_period_ns;
+};
+
+struct spmi_pmic_div_clk_cc {
+ struct clk_hw **div_clks;
I don't understand this design. Shouldn't we just allocate an
array of clkdiv structure?
This design is for addressing the invalid value passed in
spmi_pmic_div_clk_hw_get().
+ int nclks;
+};
+
+static inline struct clkdiv *to_clkdiv(struct clk_hw *hw)
+{
+ return container_of(hw, struct clkdiv, hw);
+}
+
+static inline unsigned int div_factor_to_div(unsigned int div_factor)
+{
+ if (div_factor == CLKDIV_XO_DIV_1_0)
+ return 1;
+
+ return 1 << (div_factor - CLK_SPMI_PMIC_DIV_OFFSET);
+}
+
+static inline unsigned int div_to_div_factor(unsigned int div)
+{
+ return ilog2(div) + CLK_SPMI_PMIC_DIV_OFFSET;
Maybe we should do the clamp here?
okay. address in next patch set.
+}
+
+static bool is_spmi_pmic_clkdiv_enabled(struct clkdiv *clkdiv)
+{
+ unsigned int val = 0;
+
+ regmap_read(clkdiv->regmap, clkdiv->base + REG_EN_CTL,
+ &val);
+ return ((val & REG_EN_MASK) == REG_EN_SET) ? true : false;
+}
+
+static int spmi_pmic_clkdiv_set_enable_state(struct clkdiv *clkdiv,
+ bool enable_state)
+{
+ int rc;
+
+ rc = regmap_update_bits(clkdiv->regmap, clkdiv->base + REG_EN_CTL,
+ REG_EN_MASK,
+ (enable_state == true) ? REG_EN_SET : 0);
+ if (rc)
+ return rc;
+
+ if (enable_state == true)
+ ndelay(ENABLE_DELAY_NS(clkdiv->cxo_period_ns,
+ div_factor_to_div(clkdiv->div_factor)));
+ else
+ ndelay(DISABLE_DELAY_NS(clkdiv->cxo_period_ns,
+ div_factor_to_div(clkdiv->div_factor)));
+
+ return rc;
+}
+
+static int spmi_pmic_clkdiv_config_freq_div(struct clkdiv *clkdiv,
+ unsigned int div)
+{
+ unsigned int div_factor;
+ bool enabled;
+ int rc;
+
+ div_factor = div_to_div_factor(div);
+ if (div_factor <= 0 || div_factor >= CLKDIV_MAX_ALLOWED)
div_factor is unsigned. It can't be less than 0.
okay. address in next patch set.
+ return -EINVAL;
+
+ enabled = is_spmi_pmic_clkdiv_enabled(clkdiv);
+ if (enabled) {
+ rc = spmi_pmic_clkdiv_set_enable_state(clkdiv, false);
+ if (rc)
+ return rc;
This races with clk_enable() on the same clk. You'll need some
sort of local lock to make sure set_rate() and enable don't race
with each other.
okay. address in next patch set.
+ }
+
+ rc = regmap_update_bits(clkdiv->regmap,
+ clkdiv->base + REG_DIV_CTL1,
+ DIV_CTL1_DIV_FACTOR_MASK, div_factor);
+ if (rc)
+ return rc;
+
+ clkdiv->div_factor = div_factor;
+
+ if (enabled)
+ rc = spmi_pmic_clkdiv_set_enable_state(clkdiv, true);
+
+ return rc;
+}
+
+static int clk_spmi_pmic_div_enable(struct clk_hw *hw)
+{
+ struct clkdiv *clkdiv = to_clkdiv(hw);
+
+ return spmi_pmic_clkdiv_set_enable_state(clkdiv, true);
+}
+
+static void clk_spmi_pmic_div_disable(struct clk_hw *hw)
+{
+ struct clkdiv *clkdiv = to_clkdiv(hw);
+
+ spmi_pmic_clkdiv_set_enable_state(clkdiv, false);
+}
+
+static long clk_spmi_pmic_div_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ unsigned long new_rate;
+ unsigned int div, div_factor;
+
+ div = DIV_ROUND_UP(*parent_rate, rate);
+ div_factor = div_to_div_factor(div);
+ if (div_factor >= CLKDIV_MAX_ALLOWED)
+ div_factor = CLKDIV_MAX_ALLOWED - 1;
min()?
okay. address in next patch set.
+ new_rate = *parent_rate / div_factor_to_div(div_factor);
+
+ return new_rate;
+}
+
+static unsigned long clk_spmi_pmic_div_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clkdiv *clkdiv = to_clkdiv(hw);
+ unsigned long rate;
+
+ rate = parent_rate / div_factor_to_div(clkdiv->div_factor);
+
+ return rate;
+}
+
+static int clk_spmi_pmic_div_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clkdiv *clkdiv = to_clkdiv(hw);
+ int rc = 0;
Please don't assign variables that are then reassigned right
after.
okay. address in next patch set.
+
+ rc = spmi_pmic_clkdiv_config_freq_div(clkdiv, parent_rate / rate);
+
And also just return things when you can instead of assigning
them to local variables to return after.
okay. address in next patch set.
+ return rc;
+}
+
+static const struct clk_ops clk_spmi_pmic_div_ops = {
+ .enable = clk_spmi_pmic_div_enable,
+ .disable = clk_spmi_pmic_div_disable,
+ .set_rate = clk_spmi_pmic_div_set_rate,
+ .recalc_rate = clk_spmi_pmic_div_recalc_rate,
+ .round_rate = clk_spmi_pmic_div_round_rate,
+};
+
+static struct clk_hw *spmi_pmic_div_clk_hw_get(struct of_phandle_args *clkspec,
+ void *data)
+{
+ struct spmi_pmic_div_clk_cc *clk_cc = data;
+ unsigned int idx = clkspec->args[0];
+
+ if (idx >= clk_cc->nclks) {
+ pr_err("%s: invalid index %u\n", __func__, idx);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return clk_cc->div_clks[idx];
+}
+
+#define SPMI_PMIC_DIV_CLK_ADDRESS_RANGE 0x100
SPMI_PMIC_DIV_CLK_SIZE?
okay. address in next patch set.
+#define SPMI_PMIC_DIV_CLK_ID_OFFSET 1
+
+static int spmi_pmic_clkdiv_probe(struct platform_device *pdev)
+{
+ struct spmi_pmic_div_clk_cc *clk_cc;
+ struct clk_init_data init = {0};
Drop the 0 part.
okay. address in next patch set.
+ struct clkdiv *clkdiv;
+ struct clk *cxo;
+ struct regmap *regmap;
+ struct device *dev = &pdev->dev;
+ const char *parent_name;
+ int nclks, i, rc, cxo_hz;
+ u32 reg[2], start, size;
+
+ rc = of_property_read_u32_array(dev->of_node, "reg", reg, 2);
Oh hm... I think I suggested we count the size, but that may not
work. The SPMI node has #address-cells = 1 and #size-cells = 0.
So the reg property will only have one cell and it will be the
offset. We could count the interrupts. Or we could count
clock-output-names. Or we can match a certain PMIC compatible
string and then know the size from some hardcoded number in this
driver.
okay. address in next patch set.
+ if (rc < 0) {
+ dev_err(dev, "reg property reading failed\n");
+ return rc;
+ }
+ start = reg[0];
+ size = reg[1];
+
+ nclks = size / SPMI_PMIC_DIV_CLK_ADDRESS_RANGE;
+ if (nclks == 0) {
+ dev_err(dev, "no div clocks assigned\n");
This should never happen?
okay. remove it in next patch set.
+ return -ENODEV;
+ }
+
+ regmap = dev_get_regmap(dev->parent, NULL);
+ if (!regmap) {
+ dev_err(dev, "Couldn't get parent's regmap\n");
+ return -EINVAL;
+ }
+
+ clkdiv = devm_kcalloc(dev, nclks, sizeof(*clkdiv), GFP_KERNEL);
+ if (!clkdiv)
+ return -ENOMEM;
+
+ clk_cc = devm_kzalloc(&pdev->dev, sizeof(*clk_cc), GFP_KERNEL);
+ if (!clk_cc)
+ return -ENOMEM;
+
+ clk_cc->div_clks = devm_kcalloc(&pdev->dev, nclks,
+ sizeof(*clk_cc->div_clks), GFP_KERNEL);
+ if (!clk_cc->div_clks)
+ return -ENOMEM;
+
+ /* Read parent clock rate */
That's obvious.
okay. remove it in next patch set.
+ cxo = of_clk_get(dev->of_node, 0);
Just use clk_get() instead? This is a platform driver after all.
okay. address in next patch set.
+ if (IS_ERR(cxo)) {
+ rc = PTR_ERR(cxo);
+ if (rc != -EPROBE_DEFER)
+ dev_err(dev, "failed to get xo clock");
+ return rc;
+ }
+ cxo_hz = clk_get_rate(cxo);
+ clk_put(cxo);
+
+ parent_name = of_clk_get_parent_name(dev->of_node, 0);
+ if (!parent_name) {
+ dev_err(dev, "missing parent clock\n");
+ return -ENODEV;
+ }
+ dev_dbg(dev, "parent is: %s\n", parent_name);
Remove?
okay. address in next patch set.
+
+ init.parent_names = &parent_name;
+ init.num_parents = parent_name ? 1 : 0;
+ init.ops = &clk_spmi_pmic_div_ops;
+ init.flags = 0;
+
+ for (i = 0; i < nclks; i++) {
+ clkdiv[i].base = start + i * SPMI_PMIC_DIV_CLK_ADDRESS_RANGE;
+ clkdiv[i].regmap = regmap;
+ clkdiv[i].cxo_period_ns = NSEC_PER_SEC / cxo_hz;
+ init.name = kasprintf(GFP_KERNEL, "div_clk%d",
+ i + SPMI_PMIC_DIV_CLK_ID_OFFSET);
We don't need a define for 1.
+ clkdiv[i].hw.init = &init;
+ rc = devm_clk_hw_register(dev, &clkdiv[i].hw);
+ if (rc)
We leak init.name here.
+ return rc;
+
+ clk_cc->div_clks[i] = &clkdiv[i].hw;
+ kfree(init.name); /* clock framework made a copy of the name */
+ }
+
+ clk_cc->nclks = nclks;
+ rc = of_clk_add_hw_provider(pdev->dev.of_node, spmi_pmic_div_clk_hw_get,
+ clk_cc);
Urgh, we really need this devmified. Patch coming tomorrow. For
now, you need a remove function for driver unbinding to
unregister the provider.
okay. address in next patch set.
+ return rc;
+}
+
+static const struct of_device_id spmi_pmic_clkdiv_match_table[] = {
+ { .compatible = "qcom,spmi-pmic-clkdiv" },
I'm not sure we call it this in other places. How about
qcom,spmi-clkdiv and then have specific one for the pmic as well
in case we ever care in the future like qcom,pm8916-clkdiv, etc.
okay. address in next patch set.
+ {}
+};
+MODULE_DEVICE_TABLE(of, spmi_pmic_clkdiv_match_table);
+
+static struct platform_driver spmi_pmic_clkdiv_driver = {
+ .driver = {
+ .name = "qcom,spmi-pmic-clkdiv",
+ .of_match_table = spmi_pmic_clkdiv_match_table,
+ },
+ .probe = spmi_pmic_clkdiv_probe,
+};
+module_platform_driver(spmi_pmic_clkdiv_driver);
+
+MODULE_DESCRIPTION("spmi pmic clkdiv driver");
QCOM SPMI PMIC clkdiv driver?
okay. address in next patch set.
+MODULE_LICENSE("GPL v2");
diff --git a/include/dt-bindings/clock/spmi_pmic_clk_div.h b/include/dt-bindings/clock/spmi_pmic_clk_div.h
new file mode 100644
index 0000000..25d035d
--- /dev/null
+++ b/include/dt-bindings/clock/spmi_pmic_clk_div.h
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2017, 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.
+ */
+
+#ifndef _DT_BINDINGS_SPMI_PMIC_CLK_DIV_H
+#define _DT_BINDINGS_SPMI_PMIC_CLK_DIV_H
+
+#define CLKDIV1 0
1 is 0...
+#define CLKDIV2 1
2 is 1...
+#define CLKDIV3 2
How about we offset the index once and then drop the header file?
okay. address in next patch set.