* [PATCH v3 1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper
2016-06-17 19:58 [PATCH v3 0/4] pwm: add support for ChromeOS EC PWM Brian Norris
@ 2016-06-17 19:58 ` Brian Norris
2016-06-17 21:41 ` [v3,1/4] " Guenter Roeck
2016-06-17 19:58 ` [PATCH v3 2/4] mfd: cros_ec: add EC_PWM function definitions Brian Norris
` (2 subsequent siblings)
3 siblings, 1 reply; 15+ messages in thread
From: Brian Norris @ 2016-06-17 19:58 UTC (permalink / raw)
To: Lee Jones, Thierry Reding, Olof Johansson
Cc: linux-kernel, Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso,
Brian Norris
From: Tomeu Vizoso <tomeu.vizoso@collabora.com>
So that callers of cros_ec_cmd_xfer don't have to repeat boilerplate
code when checking for errors from the EC side.
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---
v3:
* successfully spell success
v2:
* no change
---
drivers/platform/chrome/cros_ec_proto.c | 15 +++++++++++++++
include/linux/mfd/cros_ec.h | 18 ++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index b6e161f71b26..ecc544c728f0 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -380,3 +380,18 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
return ret;
}
EXPORT_SYMBOL(cros_ec_cmd_xfer);
+
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
+ struct cros_ec_command *msg)
+{
+ int ret;
+
+ ret = cros_ec_cmd_xfer(ec_dev, msg);
+ if (ret < 0)
+ dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
+ else if (msg->result != EC_RES_SUCCESS)
+ return -EECRESULT - msg->result;
+
+ return ret;
+}
+EXPORT_SYMBOL(cros_ec_cmd_xfer_status);
diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 64184d27e3cd..7671704aa2d5 100644
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -40,6 +40,9 @@
#define EC_MAX_REQUEST_OVERHEAD 1
#define EC_MAX_RESPONSE_OVERHEAD 2
+/* ec_command return value for non-success result from EC */
+#define EECRESULT 1000
+
/*
* Command interface between EC and AP, for LPC, I2C and SPI interfaces.
*/
@@ -226,6 +229,21 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg);
/**
+ * cros_ec_cmd_xfer_status - Send a command to the ChromeOS EC
+ *
+ * This function is identical to cros_ec_cmd_xfer, except it returns success
+ * status only if both the command was transmitted successfully and the EC
+ * replied with success status. It's not necessary to check msg->result when
+ * using this function.
+ *
+ * @ec_dev: EC device
+ * @msg: Message to write
+ * @return: Num. of bytes transferred on success, <0 on failure
+ */
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
+ struct cros_ec_command *msg);
+
+/**
* cros_ec_remove - Remove a ChromeOS EC
*
* Call this to deregister a ChromeOS EC, then clean up any private data.
--
2.8.0.rc3.226.g39d4020
^ permalink raw reply related [flat|nested] 15+ messages in thread* Re: [v3,1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper
2016-06-17 19:58 ` [PATCH v3 1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper Brian Norris
@ 2016-06-17 21:41 ` Guenter Roeck
2016-06-18 1:08 ` Brian Norris
0 siblings, 1 reply; 15+ messages in thread
From: Guenter Roeck @ 2016-06-17 21:41 UTC (permalink / raw)
To: Brian Norris
Cc: Lee Jones, Thierry Reding, Olof Johansson, linux-kernel,
Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso
On Fri, Jun 17, 2016 at 12:58:12PM -0700, Brian Norris wrote:
> From: Tomeu Vizoso <tomeu.vizoso@collabora.com>
>
> So that callers of cros_ec_cmd_xfer don't have to repeat boilerplate
> code when checking for errors from the EC side.
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Reviewed-by: Benson Leung <bleung@chromium.org>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> Acked-by: Lee Jones <lee.jones@linaro.org>
> Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
> v3:
> * successfully spell success
>
> v2:
> * no change
> ---
> drivers/platform/chrome/cros_ec_proto.c | 15 +++++++++++++++
> include/linux/mfd/cros_ec.h | 18 ++++++++++++++++++
> 2 files changed, 33 insertions(+)
>
> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
> index b6e161f71b26..ecc544c728f0 100644
> --- a/drivers/platform/chrome/cros_ec_proto.c
> +++ b/drivers/platform/chrome/cros_ec_proto.c
> @@ -380,3 +380,18 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
> return ret;
> }
> EXPORT_SYMBOL(cros_ec_cmd_xfer);
> +
> +int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
> + struct cros_ec_command *msg)
> +{
> + int ret;
> +
> + ret = cros_ec_cmd_xfer(ec_dev, msg);
> + if (ret < 0)
> + dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
> + else if (msg->result != EC_RES_SUCCESS)
> + return -EECRESULT - msg->result;
I have been wondering about the error return codes here, and if they should be
converted to standard Linux error codes. For example, I just hit error -1003
with a driver I am working on. This translates to EC_RES_INVALID_PARAM, or,
in Linux terms, -EINVAL. I think it would be better to use standard error
codes, especially since some of the errors are logged.
Guenter
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [v3,1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper
2016-06-17 21:41 ` [v3,1/4] " Guenter Roeck
@ 2016-06-18 1:08 ` Brian Norris
2016-06-18 4:12 ` Guenter Roeck
2016-06-18 17:09 ` Guenter Roeck
0 siblings, 2 replies; 15+ messages in thread
From: Brian Norris @ 2016-06-18 1:08 UTC (permalink / raw)
To: Guenter Roeck
Cc: Lee Jones, Thierry Reding, Olof Johansson, linux-kernel,
Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso
On Fri, Jun 17, 2016 at 02:41:51PM -0700, Guenter Roeck wrote:
> On Fri, Jun 17, 2016 at 12:58:12PM -0700, Brian Norris wrote:
> > +int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
> > + struct cros_ec_command *msg)
> > +{
> > + int ret;
> > +
> > + ret = cros_ec_cmd_xfer(ec_dev, msg);
> > + if (ret < 0)
> > + dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
> > + else if (msg->result != EC_RES_SUCCESS)
> > + return -EECRESULT - msg->result;
>
> I have been wondering about the error return codes here, and if they should be
> converted to standard Linux error codes. For example, I just hit error -1003
> with a driver I am working on. This translates to EC_RES_INVALID_PARAM, or,
> in Linux terms, -EINVAL. I think it would be better to use standard error
> codes, especially since some of the errors are logged.
How do you propose we do that? Do all of the following become EINVAL?
EC_RES_INVALID_COMMAND
EC_RES_INVALID_PARAM
EC_RES_INVALID_VERSION
EC_RES_INVALID_HEADER
We lose a lot of information that way. And particularly, cros_ec_num_pwms()
won't be able to count as accurately. But I can just go back to not using this
API if that's what you'd like...
Brian
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [v3,1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper
2016-06-18 1:08 ` Brian Norris
@ 2016-06-18 4:12 ` Guenter Roeck
[not found] ` <5764CA24.1080803-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
2016-06-18 17:09 ` Guenter Roeck
1 sibling, 1 reply; 15+ messages in thread
From: Guenter Roeck @ 2016-06-18 4:12 UTC (permalink / raw)
To: Brian Norris
Cc: Lee Jones, Thierry Reding, Olof Johansson, linux-kernel,
Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso
On 06/17/2016 06:08 PM, Brian Norris wrote:
> On Fri, Jun 17, 2016 at 02:41:51PM -0700, Guenter Roeck wrote:
>> On Fri, Jun 17, 2016 at 12:58:12PM -0700, Brian Norris wrote:
>>> +int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
>>> + struct cros_ec_command *msg)
>>> +{
>>> + int ret;
>>> +
>>> + ret = cros_ec_cmd_xfer(ec_dev, msg);
>>> + if (ret < 0)
>>> + dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
>>> + else if (msg->result != EC_RES_SUCCESS)
>>> + return -EECRESULT - msg->result;
>>
>> I have been wondering about the error return codes here, and if they should be
>> converted to standard Linux error codes. For example, I just hit error -1003
>> with a driver I am working on. This translates to EC_RES_INVALID_PARAM, or,
>> in Linux terms, -EINVAL. I think it would be better to use standard error
>> codes, especially since some of the errors are logged.
>
> How do you propose we do that? Do all of the following become EINVAL?
>
> EC_RES_INVALID_COMMAND
> EC_RES_INVALID_PARAM
> EC_RES_INVALID_VERSION
> EC_RES_INVALID_HEADER
>
Personal preference, but yes.
> We lose a lot of information that way. And particularly, cros_ec_num_pwms()
> won't be able to count as accurately. But I can just go back to not using this
You lost me there, sorry.
> API if that's what you'd like...
>
That isn't what I suggested.
Guenter
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [v3,1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper
2016-06-18 1:08 ` Brian Norris
2016-06-18 4:12 ` Guenter Roeck
@ 2016-06-18 17:09 ` Guenter Roeck
[not found] ` <5765805A.5070407-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
1 sibling, 1 reply; 15+ messages in thread
From: Guenter Roeck @ 2016-06-18 17:09 UTC (permalink / raw)
To: Brian Norris
Cc: Lee Jones, Thierry Reding, Olof Johansson, linux-kernel,
Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso
On 06/17/2016 06:08 PM, Brian Norris wrote:
> On Fri, Jun 17, 2016 at 02:41:51PM -0700, Guenter Roeck wrote:
>> On Fri, Jun 17, 2016 at 12:58:12PM -0700, Brian Norris wrote:
>>> +int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
>>> + struct cros_ec_command *msg)
>>> +{
>>> + int ret;
>>> +
>>> + ret = cros_ec_cmd_xfer(ec_dev, msg);
>>> + if (ret < 0)
>>> + dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
>>> + else if (msg->result != EC_RES_SUCCESS)
>>> + return -EECRESULT - msg->result;
>>
>> I have been wondering about the error return codes here, and if they should be
>> converted to standard Linux error codes. For example, I just hit error -1003
>> with a driver I am working on. This translates to EC_RES_INVALID_PARAM, or,
>> in Linux terms, -EINVAL. I think it would be better to use standard error
>> codes, especially since some of the errors are logged.
>
> How do you propose we do that? Do all of the following become EINVAL?
>
> EC_RES_INVALID_COMMAND
-EOPNOTSUPP
> EC_RES_INVALID_PARAM
-EINVAL or -EBADMSG
> EC_RES_INVALID_VERSION
-EPROTO or -EBADR or -EBADE or -EBADRQC or -EPROTOOPT
> EC_RES_INVALID_HEADER
-EPROTO or -EBADR or -EBADE
Doesn't look that bad to me. Also, the raw error could still be logged,
for example with dev_dbg().
Guenter
>
> We lose a lot of information that way. And particularly, cros_ec_num_pwms()
> won't be able to count as accurately. But I can just go back to not using this
> API if that's what you'd like...
>
> Brian
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 2/4] mfd: cros_ec: add EC_PWM function definitions
2016-06-17 19:58 [PATCH v3 0/4] pwm: add support for ChromeOS EC PWM Brian Norris
2016-06-17 19:58 ` [PATCH v3 1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper Brian Norris
@ 2016-06-17 19:58 ` Brian Norris
2016-06-28 15:31 ` Lee Jones
2016-06-17 19:58 ` [PATCH v3 3/4] doc: dt: pwm: add binding for ChromeOS EC PWM Brian Norris
2016-06-17 19:58 ` [PATCH v3 4/4] pwm: add ChromeOS EC PWM driver Brian Norris
3 siblings, 1 reply; 15+ messages in thread
From: Brian Norris @ 2016-06-17 19:58 UTC (permalink / raw)
To: Lee Jones, Thierry Reding, Olof Johansson
Cc: linux-kernel, Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso,
Brian Norris
The EC_CMD_PWM_{GET,SET}_DUTY commands allow us to control a PWM that is
attached to the EC, rather than the main host SoC. The API provides
functionality-based (e.g., keyboard light, backlight) or index-based
addressing of the PWM(s). Duty cycles are represented by a 16-bit value,
where 0 maps to 0% duty cycle and U16_MAX maps to 100%. The period
cannot be controlled.
This command set is more generic than, e.g.,
EC_CMD_PWM_{GET,SET}_KEYBOARD_BACKLIGHT and could possibly used to
replace it on future products.
Let's update the command header to include the definitions.
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
v3:
* convert from 65535 to 0xffff
v2:
* no changes
---
include/linux/mfd/cros_ec_commands.h | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
index 13b630c10d4c..7e7a8d4b4551 100644
--- a/include/linux/mfd/cros_ec_commands.h
+++ b/include/linux/mfd/cros_ec_commands.h
@@ -949,6 +949,37 @@ struct ec_params_pwm_set_fan_duty {
uint32_t percent;
} __packed;
+#define EC_CMD_PWM_SET_DUTY 0x25
+/* 16 bit duty cycle, 0xffff = 100% */
+#define EC_PWM_MAX_DUTY 0xffff
+
+enum ec_pwm_type {
+ /* All types, indexed by board-specific enum pwm_channel */
+ EC_PWM_TYPE_GENERIC = 0,
+ /* Keyboard backlight */
+ EC_PWM_TYPE_KB_LIGHT,
+ /* Display backlight */
+ EC_PWM_TYPE_DISPLAY_LIGHT,
+ EC_PWM_TYPE_COUNT,
+};
+
+struct ec_params_pwm_set_duty {
+ uint16_t duty; /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
+ uint8_t pwm_type; /* ec_pwm_type */
+ uint8_t index; /* Type-specific index, or 0 if unique */
+} __packed;
+
+#define EC_CMD_PWM_GET_DUTY 0x26
+
+struct ec_params_pwm_get_duty {
+ uint8_t pwm_type; /* ec_pwm_type */
+ uint8_t index; /* Type-specific index, or 0 if unique */
+} __packed;
+
+struct ec_response_pwm_get_duty {
+ uint16_t duty; /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
+} __packed;
+
/*****************************************************************************/
/*
* Lightbar commands. This looks worse than it is. Since we only use one HOST
--
2.8.0.rc3.226.g39d4020
^ permalink raw reply related [flat|nested] 15+ messages in thread* Re: [PATCH v3 2/4] mfd: cros_ec: add EC_PWM function definitions
2016-06-17 19:58 ` [PATCH v3 2/4] mfd: cros_ec: add EC_PWM function definitions Brian Norris
@ 2016-06-28 15:31 ` Lee Jones
0 siblings, 0 replies; 15+ messages in thread
From: Lee Jones @ 2016-06-28 15:31 UTC (permalink / raw)
To: Brian Norris
Cc: Thierry Reding, Olof Johansson, linux-kernel, Doug Anderson,
Brian Norris, linux-pwm, devicetree, Boris Brezillon,
Stephen Barber, Javier Martinez Canillas, Benson Leung,
Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso
On Fri, 17 Jun 2016, Brian Norris wrote:
> The EC_CMD_PWM_{GET,SET}_DUTY commands allow us to control a PWM that is
> attached to the EC, rather than the main host SoC. The API provides
> functionality-based (e.g., keyboard light, backlight) or index-based
> addressing of the PWM(s). Duty cycles are represented by a 16-bit value,
> where 0 maps to 0% duty cycle and U16_MAX maps to 100%. The period
> cannot be controlled.
>
> This command set is more generic than, e.g.,
> EC_CMD_PWM_{GET,SET}_KEYBOARD_BACKLIGHT and could possibly used to
> replace it on future products.
>
> Let's update the command header to include the definitions.
>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
> v3:
> * convert from 65535 to 0xffff
>
> v2:
> * no changes
> ---
> include/linux/mfd/cros_ec_commands.h | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
For my own reference:
Acked-by: Lee Jones <lee.jones@linaro.org>
> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
> index 13b630c10d4c..7e7a8d4b4551 100644
> --- a/include/linux/mfd/cros_ec_commands.h
> +++ b/include/linux/mfd/cros_ec_commands.h
> @@ -949,6 +949,37 @@ struct ec_params_pwm_set_fan_duty {
> uint32_t percent;
> } __packed;
>
> +#define EC_CMD_PWM_SET_DUTY 0x25
> +/* 16 bit duty cycle, 0xffff = 100% */
> +#define EC_PWM_MAX_DUTY 0xffff
> +
> +enum ec_pwm_type {
> + /* All types, indexed by board-specific enum pwm_channel */
> + EC_PWM_TYPE_GENERIC = 0,
> + /* Keyboard backlight */
> + EC_PWM_TYPE_KB_LIGHT,
> + /* Display backlight */
> + EC_PWM_TYPE_DISPLAY_LIGHT,
> + EC_PWM_TYPE_COUNT,
> +};
> +
> +struct ec_params_pwm_set_duty {
> + uint16_t duty; /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
> + uint8_t pwm_type; /* ec_pwm_type */
> + uint8_t index; /* Type-specific index, or 0 if unique */
> +} __packed;
> +
> +#define EC_CMD_PWM_GET_DUTY 0x26
> +
> +struct ec_params_pwm_get_duty {
> + uint8_t pwm_type; /* ec_pwm_type */
> + uint8_t index; /* Type-specific index, or 0 if unique */
> +} __packed;
> +
> +struct ec_response_pwm_get_duty {
> + uint16_t duty; /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
> +} __packed;
> +
> /*****************************************************************************/
> /*
> * Lightbar commands. This looks worse than it is. Since we only use one HOST
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v3 3/4] doc: dt: pwm: add binding for ChromeOS EC PWM
2016-06-17 19:58 [PATCH v3 0/4] pwm: add support for ChromeOS EC PWM Brian Norris
2016-06-17 19:58 ` [PATCH v3 1/4] mfd: cros_ec: Add cros_ec_cmd_xfer_status helper Brian Norris
2016-06-17 19:58 ` [PATCH v3 2/4] mfd: cros_ec: add EC_PWM function definitions Brian Norris
@ 2016-06-17 19:58 ` Brian Norris
2016-06-17 19:58 ` [PATCH v3 4/4] pwm: add ChromeOS EC PWM driver Brian Norris
3 siblings, 0 replies; 15+ messages in thread
From: Brian Norris @ 2016-06-17 19:58 UTC (permalink / raw)
To: Lee Jones, Thierry Reding, Olof Johansson
Cc: linux-kernel, Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso,
Brian Norris
The ChromeOS Embedded Controller can support controlling its attached
PWMs via its host-command interface. The number of supported PWMs varies
on a per-board basis, but we can autodetect this by checking the error
codes, so we don't need an extra property for this. And because the EC
only allows specifying the duty cycle and not the period, we don't
specify the period via pwm-cells, and instead have only support 1 cell
-- to specify the index.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
---
v3:
* add Rob's ack
v2: dropped the "google,max-pwms" property
---
.../devicetree/bindings/pwm/google,cros-ec-pwm.txt | 23 ++++++++++++++++++++++
1 file changed, 23 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt
diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt
new file mode 100644
index 000000000000..472bd46ab5a4
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt
@@ -0,0 +1,23 @@
+* PWM controlled by ChromeOS EC
+
+Google's ChromeOS EC PWM is a simple PWM attached to the Embedded Controller
+(EC) and controlled via a host-command interface.
+
+An EC PWM node should be only found as a sub-node of the EC node (see
+Documentation/devicetree/bindings/mfd/cros-ec.txt).
+
+Required properties:
+- compatible: Must contain "google,cros-ec-pwm"
+- #pwm-cells: Should be 1. The cell specifies the PWM index.
+
+Example:
+ cros-ec@0 {
+ compatible = "google,cros-ec-spi";
+
+ ...
+
+ cros_ec_pwm: ec-pwm {
+ compatible = "google,cros-ec-pwm";
+ #pwm-cells = <1>;
+ };
+ };
--
2.8.0.rc3.226.g39d4020
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v3 4/4] pwm: add ChromeOS EC PWM driver
2016-06-17 19:58 [PATCH v3 0/4] pwm: add support for ChromeOS EC PWM Brian Norris
` (2 preceding siblings ...)
2016-06-17 19:58 ` [PATCH v3 3/4] doc: dt: pwm: add binding for ChromeOS EC PWM Brian Norris
@ 2016-06-17 19:58 ` Brian Norris
3 siblings, 0 replies; 15+ messages in thread
From: Brian Norris @ 2016-06-17 19:58 UTC (permalink / raw)
To: Lee Jones, Thierry Reding, Olof Johansson
Cc: linux-kernel, Doug Anderson, Brian Norris, linux-pwm, devicetree,
Boris Brezillon, Stephen Barber, Javier Martinez Canillas,
Benson Leung, Enric Balletbo, Randall Spangler, Shawn Nematbakhsh,
Dmitry Torokhov, Todd Broch, Gwendal Grignou, Tomeu Vizoso,
Brian Norris
Use the new ChromeOS EC EC_CMD_PWM_{GET,SET}_DUTY commands to control
one or more PWMs attached to the Embedded Controller. Because the EC
allows us to modify the duty cycle (as a percentage, where U16_MAX is
100%) but not the period, we assign the period a fixed value of
EC_PWM_MAX_DUTY and reject all attempts to change it.
This driver supports only device tree at the moment, because that
provides a very flexible way of describing the relationship between PWMs
and their consumer devices (e.g., backlight). On a non-DT system, we'll
probably want to use the non-GENERIC addressing (i.e., we'll need to
make special device instances that will use EC_PWM_TYPE_KB_LIGHT or
EC_PWM_TYPE_DISPLAY_LIGHT), as well as the relatively inflexible
pwm_lookup infrastructure for matching devices. Defer that work for now.
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
v3:
* handle 'disabled' properly in apply(), since EC conflates 0
duty-cycle and disabled state
v2:
* refactor some abstractions to separate the PWM layer handling from
the cros_ec handling
* remove dynamic kzalloc()'s and rely on on-stack memory instead
* auto-probe the number of PWMs supported
---
drivers/pwm/Kconfig | 7 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-cros-ec.c | 246 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 254 insertions(+)
create mode 100644 drivers/pwm/pwm-cros-ec.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c182efc62c7b..4f2b16a50f42 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -137,6 +137,13 @@ config PWM_CRC
Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM
control.
+config PWM_CROS_EC
+ tristate "ChromeOS EC PWM driver"
+ depends on MFD_CROS_EC
+ help
+ PWM driver for exposing a PWM attached to the ChromeOS Embedded
+ Controller.
+
config PWM_EP93XX
tristate "Cirrus Logic EP93xx PWM support"
depends on ARCH_EP93XX
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index dd35bc121a18..ffde923cf3df 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
obj-$(CONFIG_PWM_BRCMSTB) += pwm-brcmstb.o
obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o
obj-$(CONFIG_PWM_CRC) += pwm-crc.o
+obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o
obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o
obj-$(CONFIG_PWM_IMG) += pwm-img.o
diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
new file mode 100644
index 000000000000..ec3bb8ec4e8a
--- /dev/null
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -0,0 +1,246 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2, as published by
+ * the Free Software Foundation.
+ *
+ * Expose a PWM controlled by the ChromeOS EC to the host processor.
+ */
+
+#include <linux/module.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+/**
+ * struct cros_ec_pwm_device - Driver data for EC PWM
+ *
+ * @dev: Device node
+ * @ec: Pointer to EC device
+ * @chip: PWM controller chip
+ */
+struct cros_ec_pwm_device {
+ struct device *dev;
+ struct cros_ec_device *ec;
+ struct pwm_chip chip;
+};
+
+static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c)
+{
+ return container_of(c, struct cros_ec_pwm_device, chip);
+}
+
+static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
+{
+ struct {
+ struct cros_ec_command msg;
+ struct ec_params_pwm_set_duty params;
+ } buf;
+ struct ec_params_pwm_set_duty *params = &buf.params;
+ struct cros_ec_command *msg = &buf.msg;
+
+ memset(&buf, 0, sizeof(buf));
+
+ msg->version = 0;
+ msg->command = EC_CMD_PWM_SET_DUTY;
+ msg->insize = 0;
+ msg->outsize = sizeof(*params);
+
+ params->duty = duty;
+ params->pwm_type = EC_PWM_TYPE_GENERIC;
+ params->index = index;
+
+ return cros_ec_cmd_xfer_status(ec, msg);
+}
+
+static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
+{
+ struct {
+ struct cros_ec_command msg;
+ union {
+ struct ec_params_pwm_get_duty params;
+ struct ec_response_pwm_get_duty resp;
+ };
+ } buf;
+ struct ec_params_pwm_get_duty *params = &buf.params;
+ struct ec_response_pwm_get_duty *resp = &buf.resp;
+ struct cros_ec_command *msg = &buf.msg;
+ int ret;
+
+ memset(&buf, 0, sizeof(buf));
+
+ msg->version = 0;
+ msg->command = EC_CMD_PWM_GET_DUTY;
+ msg->insize = sizeof(*params);
+ msg->outsize = sizeof(*resp);
+
+ params->pwm_type = EC_PWM_TYPE_GENERIC;
+ params->index = index;
+
+ ret = cros_ec_cmd_xfer_status(ec, msg);
+ if (ret < 0)
+ return ret;
+
+ return resp->duty;
+}
+
+static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
+ int duty_cycle;
+
+ /* The EC won't let us change the period */
+ if (state->period != EC_PWM_MAX_DUTY)
+ return -EINVAL;
+
+ /*
+ * EC doesn't separate the concept of duty cycle and enabled, but
+ * kernel does. Translate.
+ */
+ duty_cycle = state->enabled ? state->duty_cycle : 0;
+
+ return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
+}
+
+static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
+ int ret;
+
+ ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
+ if (ret < 0) {
+ dev_err(chip->dev, "error getting initial duty: %d\n", ret);
+ return;
+ }
+
+ state->enabled = (ret > 0);
+ state->period = EC_PWM_MAX_DUTY;
+
+ /* Note that "disabled" and "duty cycle == 0" are treated the same */
+ state->duty_cycle = ret;
+}
+
+static struct pwm_device *
+cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
+{
+ struct pwm_device *pwm;
+
+ if (args->args[0] >= pc->npwm)
+ return ERR_PTR(-EINVAL);
+
+ pwm = pwm_request_from_chip(pc, args->args[0], NULL);
+ if (IS_ERR(pwm))
+ return pwm;
+
+ /* The EC won't let us change the period */
+ pwm->args.period = EC_PWM_MAX_DUTY;
+
+ return pwm;
+}
+
+static const struct pwm_ops cros_ec_pwm_ops = {
+ .get_state = cros_ec_pwm_get_state,
+ .apply = cros_ec_pwm_apply,
+ .owner = THIS_MODULE,
+};
+
+static int cros_ec_num_pwms(struct cros_ec_device *ec)
+{
+ int i, ret;
+
+ /* The index field is only 8 bits */
+ for (i = 0; i <= U8_MAX; i++) {
+ ret = cros_ec_pwm_get_duty(ec, i);
+ /*
+ * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM responses;
+ * everything else is treated as an error
+ */
+ if (ret == -EECRESULT - EC_RES_INVALID_COMMAND)
+ return -ENODEV;
+ else if (ret == -EECRESULT - EC_RES_INVALID_PARAM)
+ return i;
+ else if (ret < 0)
+ return ret;
+ }
+
+ return U8_MAX;
+}
+
+static int cros_ec_pwm_probe(struct platform_device *pdev)
+{
+ struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
+ struct device *dev = &pdev->dev;
+ struct cros_ec_pwm_device *ec_pwm;
+ struct pwm_chip *chip;
+ int ret;
+
+ if (!ec) {
+ dev_err(dev, "no parent EC device\n");
+ return -EINVAL;
+ }
+
+ ec_pwm = devm_kzalloc(dev, sizeof(*ec_pwm), GFP_KERNEL);
+ if (!ec_pwm)
+ return -ENOMEM;
+ chip = &ec_pwm->chip;
+ ec_pwm->ec = ec;
+
+ /* PWM chip */
+ chip->dev = dev;
+ chip->ops = &cros_ec_pwm_ops;
+ chip->of_xlate = cros_ec_pwm_xlate;
+ chip->of_pwm_n_cells = 1;
+ chip->base = -1;
+ ret = cros_ec_num_pwms(ec);
+ if (ret < 0) {
+ dev_err(dev, "Couldn't find PWMs: %d\n", ret);
+ return ret;
+ }
+ chip->npwm = ret;
+ dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);
+
+ ret = pwmchip_add(chip);
+ if (ret < 0) {
+ dev_err(dev, "cannot register PWM: %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, ec_pwm);
+
+ return ret;
+}
+
+static int cros_ec_pwm_remove(struct platform_device *dev)
+{
+ struct cros_ec_pwm_device *ec_pwm = platform_get_drvdata(dev);
+ struct pwm_chip *chip = &ec_pwm->chip;
+
+ return pwmchip_remove(chip);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id cros_ec_pwm_of_match[] = {
+ { .compatible = "google,cros-ec-pwm" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cros_ec_pwm_of_match);
+#endif
+
+static struct platform_driver cros_ec_pwm_driver = {
+ .probe = cros_ec_pwm_probe,
+ .remove = cros_ec_pwm_remove,
+ .driver = {
+ .name = "cros-ec-pwm",
+ .of_match_table = of_match_ptr(cros_ec_pwm_of_match),
+ },
+};
+module_platform_driver(cros_ec_pwm_driver);
+
+MODULE_ALIAS("platform:cros-ec-pwm");
+MODULE_DESCRIPTION("ChromeOS EC PWM driver");
+MODULE_LICENSE("GPL v2");
--
2.8.0.rc3.226.g39d4020
^ permalink raw reply related [flat|nested] 15+ messages in thread