On 10/31/2017 06:34 PM, Joel Stanley wrote:
The ASPEED SoC must deassert a reset in order to use the PWM/tach
peripheral.
The device tree bindings are updated to document the resets phandle, and
the example is updated to match what is expected for both the reset and
clock phandle. Note that the bindings should have always had the reset
controller, as the hardware is unusable without it.
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
Presumably the driver is being used. This change makes it incompatible with
existing users. This is unacceptable; after all, it is possible that the
device is taken out of reset by ROMMON or BIOS.
On top of that, the reset controller code is quite strict and issues a
backtrace if CONFIG_RESET_CONTROLLER is not enabled. Yet, there is no
dependency added on RESET_CONTROLLER. You might want to consider making
the new control optional and using devm_reset_control_get_optional_exclusive().
The DT change should be a separate patch.
More comments below.
---
.../devicetree/bindings/hwmon/aspeed-pwm-tacho.txt | 14 ++++-------
drivers/hwmon/aspeed-pwm-tacho.c | 27 +++++++++++++++++++---
2 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt b/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
index 367c8203213b..3ac02988a1a5 100644
--- a/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
+++ b/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
@@ -22,8 +22,9 @@ Required properties for pwm-tacho node:
- compatible : should be "aspeed,ast2400-pwm-tacho" for AST2400 and
"aspeed,ast2500-pwm-tacho" for AST2500.
-- clocks : a fixed clock providing input clock frequency(PWM
- and Fan Tach clock)
+- clocks : phandle to clock provider with the clock number in the second cell
+
+- resets : phandle to reset controller with the reset number in the second cell
fan subnode format:
===================
@@ -48,19 +49,14 @@ Required properties for each child node:
Examples:
-pwm_tacho_fixed_clk: fixedclk {
- compatible = "fixed-clock";
- #clock-cells = <0>;
- clock-frequency = <24000000>;
-};
-
pwm_tacho: pwmtachocontroller@1e786000 {
#address-cells = <1>;
#size-cells = <1>;
#cooling-cells = <2>;
reg = <0x1E786000 0x1000>;
compatible = "aspeed,ast2500-pwm-tacho";
- clocks = <&pwm_tacho_fixed_clk>;
+ clocks = <&syscon ASPEED_CLK_APB>;
+ resets = <&syscon ASPEED_RESET_PWM>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>;
diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c
index f914e5f41048..346a4c5952a3 100644
--- a/drivers/hwmon/aspeed-pwm-tacho.c
+++ b/drivers/hwmon/aspeed-pwm-tacho.c
@@ -7,19 +7,20 @@
*/
#include <linux/clk.h>
+#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/gpio/consumer.h>
-#include <linux/delay.h>
Unrelated change.
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
-#include <linux/of_platform.h>
#include <linux/of_device.h>
+#include <linux/of_platform.h>
Same here. I don't mind the include file reordering, but as a separate patch, please.
#include <linux/platform_device.h>
-#include <linux/sysfs.h>
#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/sysfs.h>
#include <linux/thermal.h>
/* ASPEED PWM & FAN Tach Register Definition */
@@ -181,6 +182,7 @@ struct aspeed_cooling_device {
struct aspeed_pwm_tacho_data {
struct regmap *regmap;
+ struct reset_control *rst;
unsigned long clk_freq;
bool pwm_present[8];
bool fan_tach_present[16];
@@ -931,6 +933,15 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev)
&aspeed_pwm_tacho_regmap_config);
if (IS_ERR(priv->regmap))
return PTR_ERR(priv->regmap);
+
+ priv->rst = devm_reset_control_get_exclusive(dev, NULL);
+ if (IS_ERR(priv->rst)) {
+ dev_err(dev,
+ "missing or invalid reset controller device tree entry");
+ return PTR_ERR(priv->rst);
+ }
+ reset_control_deassert(priv->rst);
+
regmap_write(priv->regmap, ASPEED_PTCR_TACH_SOURCE, 0);
regmap_write(priv->regmap, ASPEED_PTCR_TACH_SOURCE_EXT, 0);
@@ -960,6 +971,15 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev)
return PTR_ERR_OR_ZERO(hwmon);
}
+static int aspeed_pwm_tacho_remove(struct platform_device *pdev)
+{
+ struct aspeed_pwm_tacho_data *priv = platform_get_drvdata(pdev);
+
+ reset_control_deassert(priv->rst);
This seems to be quite pointless. Also, did you test this code ?
+
+ return 0;
+}
+
static const struct of_device_id of_pwm_tacho_match_table[] = {
{ .compatible = "aspeed,ast2400-pwm-tacho", },
{ .compatible = "aspeed,ast2500-pwm-tacho", },
@@ -969,6 +989,7 @@ MODULE_DEVICE_TABLE(of, of_pwm_tacho_match_table);
static struct platform_driver aspeed_pwm_tacho_driver = {
.probe = aspeed_pwm_tacho_probe,
+ .probe = aspeed_pwm_tacho_remove,
.driver = {
.name = "aspeed_pwm_tacho",
.of_match_table = of_pwm_tacho_match_table,
--
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