pwm: Modify new PWM host commands to take 16-bit duty cycle

EC_CMD_PWM_SET_DUTY / EC_CMD_PWM_GET_DUTY were recently added and are
not yet in use. Future-proof these commands by taking a 16-bit duty
cycle parameter and converting it between the [0-100] percent used by
internal EC functions.

BUG=chromium:615109
BRANCH=None
TEST=Manual on chell.
`ectool pwmsetduty kb 65535` - Verify KB backlight goes to 100%
`ectool pwmgetduty kb` - Prints 65535
`ectool pwmgetduty 0` - Prints 65535
`ectool pwmsetduty 0 0` - Verify KB backlight goes to 0%
`ectool pwmgetduty kb` - Prints 0
`ectool pwmgetduty disp` - Error res 3 (unsupported PWM type)
`ectool pwmsetduty 1` - Error res 3 (non-existent PWM index)
`ectool pwmsetduty kb 6550` +
`ectool pwmgetduty kb` - Prints 6553 (round up)
`ectool pwmsetduty kb 6560` +
`ectool pwmgetduty kb` - Prints 6553 (round down)

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: Ic6996fc6e1e69359274b2f9a1120ee7002db991c
Reviewed-on: https://chromium-review.googlesource.com/347608
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>

3 files changed, 22 insertions, 13 deletions

diff --git a/common/pwm.c b/common/pwm.c
index c689b0acac..84e242abf4 100644
--- a/common/pwm.c
+++ b/common/pwm.c
@@ -40,19 +40,25 @@ static int get_target_channel(enum pwm_channel *channel, int type, int index)
 	return *channel >= PWM_CH_COUNT;
 }
 
+/*
+ * TODO(crbug.com/615109): These host commands use 16 bit duty cycle, but
+ * all of our internal code uses percent on [0, 100]. Convert internal
+ * functions to use 16 bit duty and remove the conversions below.
+ */
 static int host_command_pwm_set_duty(struct host_cmd_handler_args *args)
 {
 	const struct ec_params_pwm_set_duty *p = args->params;
 	enum pwm_channel channel;
+	int percent;
 
-	if (p->percent > 100)
-		return EC_RES_INVALID_PARAM;
+	/* Convert 16 bit duty to percent on [0, 100] */
+	percent = DIV_ROUND_NEAREST(p->duty * 100, EC_PWM_MAX_DUTY);
 
 	if (get_target_channel(&channel, p->pwm_type, p->index))
 		return EC_RES_INVALID_PARAM;
 
-	pwm_set_duty(channel, p->percent);
-	pwm_enable(channel, p->percent > 0);
+	pwm_set_duty(channel, percent);
+	pwm_enable(channel, percent > 0);
 
 	return EC_RES_SUCCESS;
 }
@@ -70,7 +76,8 @@ static int host_command_pwm_get_duty(struct host_cmd_handler_args *args)
 	if (get_target_channel(&channel, p->pwm_type, p->index))
 		return EC_RES_INVALID_PARAM;
 
-	r->percent = pwm_get_duty(channel);
+	/* Convert percent on [0, 100] to 16 bit duty */
+	r->duty = pwm_get_duty(channel) * EC_PWM_MAX_DUTY / 100;
 	args->response_size = sizeof(*r);
 
 	return EC_RES_SUCCESS;
diff --git a/include/ec_commands.h b/include/ec_commands.h
index 27049eac5a..871dbf9662 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -1207,6 +1207,8 @@ struct ec_params_pwm_set_fan_duty_v1 {
 } __packed;
 
 #define EC_CMD_PWM_SET_DUTY 0x25
+/* 16 bit duty cycle, 65535 = 100% */
+#define EC_PWM_MAX_DUTY 65535
 
 enum ec_pwm_type {
 	/* All types, indexed by board-specific enum pwm_channel */
@@ -1219,7 +1221,7 @@ enum ec_pwm_type {
 };
 
 struct ec_params_pwm_set_duty {
-	uint8_t percent;   /* Duty cycle percent on [0, 100] */
+	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;
@@ -1232,7 +1234,7 @@ struct ec_params_pwm_get_duty {
 } __packed;
 
 struct ec_response_pwm_get_duty {
-	uint8_t percent;
+	uint16_t duty;     /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
 } __packed;
 
 /*****************************************************************************/
diff --git a/util/ectool.c b/util/ectool.c
index a1210466f5..364ec2f99f 100644
--- a/util/ectool.c
+++ b/util/ectool.c
@@ -176,13 +176,13 @@ const char help_str[] =
 	"  pwmgetnumfans\n"
 	"      Prints the number of fans present\n"
 	"  pwmgetduty\n"
-	"      Prints the current duty cycle for given PWM\n"
+	"      Prints the current 16 bit duty cycle for given PWM\n"
 	"  pwmsetfanrpm <targetrpm>\n"
 	"      Set target fan RPM\n"
 	"  pwmsetkblight <percent>\n"
 	"      Set keyboard backlight in percent\n"
 	"  pwmsetduty\n"
-	"      Set duty cycle of given PWM in percent\n"
+	"      Set 16 bit duty cycle of given PWM\n"
 	"  readtest <patternoffset> <size>\n"
 	"      Reads a pattern from the EC via LPC\n"
 	"  reboot_ec <RO|RW|cold|hibernate|disable-jump> [at-shutdown]\n"
@@ -1941,7 +1941,7 @@ int cmd_pwm_get_duty(int argc, char *argv[])
 	if (rv < 0)
 		return rv;
 
-	printf("Current PWM duty: %d\n", r.percent);
+	printf("Current PWM duty: %d\n", r.duty);
 	return 0;
 }
 
@@ -1953,7 +1953,7 @@ int cmd_pwm_set_duty(int argc, char *argv[])
 	int rv;
 
 	if (argc != 3) {
-		fprintf(stderr, "Usage: %s <pwm_idx> | kb | disp <percent>\n",
+		fprintf(stderr, "Usage: %s <pwm_idx> | kb | disp <duty>\n",
 			argv[0]);
 		return -1;
 	}
@@ -1973,9 +1973,9 @@ int cmd_pwm_set_duty(int argc, char *argv[])
 		}
 	}
 
-	p.percent = strtol(argv[2], &e, 0);
+	p.duty = strtol(argv[2], &e, 0);
 	if (e && *e) {
-		fprintf(stderr, "Bad percent.\n");
+		fprintf(stderr, "Bad duty.\n");
 		return -1;
 	}