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hc
2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771 
 kernel/drivers/pwm/pwm-cros-ec.c
....@@ -6,8 +6,8 @@
66  */
77 
88 #include <linux/module.h>
9
-#include <linux/mfd/cros_ec.h>
10
-#include <linux/mfd/cros_ec_commands.h>
9
+#include <linux/platform_data/cros_ec_commands.h>
10
+#include <linux/platform_data/cros_ec_proto.h>
1111 #include <linux/platform_device.h>
1212 #include <linux/pwm.h>
1313 #include <linux/slab.h>
....@@ -25,9 +25,37 @@
2525 	struct pwm_chip chip;
2626 };
2727 
28
+/**
29
+ * struct cros_ec_pwm - per-PWM driver data
30
+ * @duty_cycle: cached duty cycle
31
+ */
32
+struct cros_ec_pwm {
33
+	u16 duty_cycle;
34
+};
35
+
2836 static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c)
2937 {
3038 	return container_of(c, struct cros_ec_pwm_device, chip);
39
+}
40
+
41
+static int cros_ec_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
42
+{
43
+	struct cros_ec_pwm *channel;
44
+
45
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
46
+	if (!channel)
47
+		return -ENOMEM;
48
+
49
+	pwm_set_chip_data(pwm, channel);
50
+
51
+	return 0;
52
+}
53
+
54
+static void cros_ec_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
55
+{
56
+	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
57
+
58
+	kfree(channel);
3159 }
3260 
3361 static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
....@@ -53,8 +81,7 @@
5381 	return cros_ec_cmd_xfer_status(ec, msg);
5482 }
5583 
56
-static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
57
-				  u32 *result)
84
+static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
5885 {
5986 	struct {
6087 		struct cros_ec_command msg;
....@@ -79,24 +106,19 @@
79106 	params->index = index;
80107 
81108 	ret = cros_ec_cmd_xfer_status(ec, msg);
82
-	if (result)
83
-		*result = msg->result;
84109 	if (ret < 0)
85110 		return ret;
86111 
87112 	return resp->duty;
88113 }
89114 
90
-static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
91
-{
92
-	return __cros_ec_pwm_get_duty(ec, index, NULL);
93
-}
94
-
95115 static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
96
-			     struct pwm_state *state)
116
+			     const struct pwm_state *state)
97117 {
98118 	struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
99
-	int duty_cycle;
119
+	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
120
+	u16 duty_cycle;
121
+	int ret;
100122 
101123 	/* The EC won't let us change the period */
102124 	if (state->period != EC_PWM_MAX_DUTY)
....@@ -108,13 +130,20 @@
108130 	 */
109131 	duty_cycle = state->enabled ? state->duty_cycle : 0;
110132 
111
-	return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
133
+	ret = cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
134
+	if (ret < 0)
135
+		return ret;
136
+
137
+	channel->duty_cycle = state->duty_cycle;
138
+
139
+	return 0;
112140 }
113141 
114142 static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
115143 				  struct pwm_state *state)
116144 {
117145 	struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
146
+	struct cros_ec_pwm *channel = pwm_get_chip_data(pwm);
118147 	int ret;
119148 
120149 	ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
....@@ -125,9 +154,21 @@
125154 
126155 	state->enabled = (ret > 0);
127156 	state->period = EC_PWM_MAX_DUTY;
157
+	state->polarity = PWM_POLARITY_NORMAL;
128158 
129
-	/* Note that "disabled" and "duty cycle == 0" are treated the same */
130
-	state->duty_cycle = ret;
159
+	/*
160
+	 * Note that "disabled" and "duty cycle == 0" are treated the same. If
161
+	 * the cached duty cycle is not zero, used the cached duty cycle. This
162
+	 * ensures that the configured duty cycle is kept across a disable and
163
+	 * enable operation and avoids potentially confusing consumers.
164
+	 *
165
+	 * For the case of the initial hardware readout, channel->duty_cycle
166
+	 * will be 0 and the actual duty cycle read from the EC is used.
167
+	 */
168
+	if (ret == 0 && channel->duty_cycle > 0)
169
+		state->duty_cycle = channel->duty_cycle;
170
+	else
171
+		state->duty_cycle = ret;
131172 }
132173 
133174 static struct pwm_device *
....@@ -149,34 +190,41 @@
149190 }
150191 
151192 static const struct pwm_ops cros_ec_pwm_ops = {
193
+	.request = cros_ec_pwm_request,
194
+	.free = cros_ec_pwm_free,
152195 	.get_state	= cros_ec_pwm_get_state,
153196 	.apply		= cros_ec_pwm_apply,
154197 	.owner		= THIS_MODULE,
155198 };
156199 
200
+/*
201
+ * Determine the number of supported PWMs. The EC does not return the number
202
+ * of PWMs it supports directly, so we have to read the pwm duty cycle for
203
+ * subsequent channels until we get an error.
204
+ */
157205 static int cros_ec_num_pwms(struct cros_ec_device *ec)
158206 {
159207 	int i, ret;
160208 
161209 	/* The index field is only 8 bits */
162210 	for (i = 0; i <= U8_MAX; i++) {
163
-		u32 result = 0;
164
-
165
-		ret = __cros_ec_pwm_get_duty(ec, i, &result);
166
-		/* We want to parse EC protocol errors */
167
-		if (ret < 0 && !(ret == -EPROTO && result))
168
-			return ret;
169
-
211
+		ret = cros_ec_pwm_get_duty(ec, i);
170212 		/*
171213 		 * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM
172214 		 * responses; everything else is treated as an error.
215
+		 * The EC error codes map to -EOPNOTSUPP and -EINVAL,
216
+		 * so check for those.
173217 		 */
174
-		if (result == EC_RES_INVALID_COMMAND)
218
+		switch (ret) {
219
+		case -EOPNOTSUPP:	/* invalid command */
175220 			return -ENODEV;
176
-		else if (result == EC_RES_INVALID_PARAM)
221
+		case -EINVAL:		/* invalid parameter */
177222 			return i;
178
-		else if (result)
179
-			return -EPROTO;
223
+		default:
224
+			if (ret < 0)
225
+				return ret;
226
+			break;
227
+		}
180228 	}
181229 
182230 	return U8_MAX;