mfd: Support LP3974 RTC

The first releases of LP3974 have a large delay in RTC registers, which requires 2 seconds of delay after writing to a rtc register (recommended by National Semiconductor's engineers) before reading it. If "rtc_delay" field of the platform data is true, the rtc driver assumes that such delays are required. Although we have not seen LP3974s without requiring such delays, we assume that such LP3974s will be released soon (or they have done so already) and they are supported by "lp3974" without setting "rtc_delay" at the platform data. This patch adds delays with msleep when writing values to RTC registers if the platform data has rtc_delay set. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

mfd: Support LP3974 RTC
The first releases of LP3974 have a large delay in RTC registers, which requires 2 seconds of delay after writing to a rtc register (recommended by National Semiconductor's engineers) before reading it. If "rtc_delay" field of the platform data is true, the rtc driver assumes that such delays are required. Although we have not seen LP3974s without requiring such delays, we assume that such LP3974s will be released soon (or they have done so already) and they are supported by "lp3974" without setting "rtc_delay" at the platform data. This patch adds delays with msleep when writing values to RTC registers if the platform data has rtc_delay set. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
MyungJoo Ham · Samuel Ortiz
1 parent de8255ccd2
Showing 4 changed files with 83 additions and 8 deletions Side-by-side Diff
drivers/mfd/max8998.c
drivers/regulator/max8998.c
drivers/rtc/rtc-max8998.c
include/linux/mfd/max8998.h
@@ -42,6 +42,14 @@
 	},
 };
  
+static struct mfd_cell lp3974_devs[] = {
+	{
+		.name = "lp3974-pmic",
+	}, {
+		.name = "lp3974-rtc",
+	},
+};
+
 int max8998_read_reg(struct i2c_client *i2c, u8 reg, u8 *dest)
 {
 	struct max8998_dev *max8998 = i2c_get_clientdata(i2c);
  
@@ -146,10 +154,22 @@
  
 	max8998_irq_init(max8998);
  
-	ret = mfd_add_devices(max8998->dev, -1,
-			      max8998_devs, ARRAY_SIZE(max8998_devs),
-			      NULL, 0);
 	pm_runtime_set_active(max8998->dev);
+
+	switch (id->driver_data) {
+	case TYPE_LP3974:
+		ret = mfd_add_devices(max8998->dev, -1,
+				lp3974_devs, ARRAY_SIZE(lp3974_devs),
+				NULL, 0);
+		break;
+	case TYPE_MAX8998:
+		ret = mfd_add_devices(max8998->dev, -1,
+				max8998_devs, ARRAY_SIZE(max8998_devs),
+				NULL, 0);
+		break;
+	default:
+		ret = -EINVAL;
+	}
  
 	if (ret < 0)
 		goto err;
@@ -835,6 +835,12 @@
 	return 0;
 }
  
+static const struct platform_device_id max8998_pmic_id[] = {
+	{ "max8998-pmic", TYPE_MAX8998 },
+	{ "lp3974-pmic", TYPE_LP3974 },
+	{ }
+};
+
 static struct platform_driver max8998_pmic_driver = {
 	.driver = {
 		.name = "max8998-pmic",
@@ -842,6 +848,7 @@
 	},
 	.probe = max8998_pmic_probe,
 	.remove = __devexit_p(max8998_pmic_remove),
+	.id_table = max8998_pmic_id,
 };
  
 static int __init max8998_pmic_init(void)
@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/mfd/max8998.h>
 #include <linux/mfd/max8998-private.h>
+#include <linux/delay.h>
  
 #define MAX8998_RTC_SEC			0x00
 #define MAX8998_RTC_MIN			0x01
@@ -73,6 +74,7 @@
 	struct i2c_client	*rtc;
 	struct rtc_device	*rtc_dev;
 	int irq;
+	bool lp3974_bug_workaround;
 };
  
 static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
  
@@ -124,10 +126,16 @@
 {
 	struct max8998_rtc_info *info = dev_get_drvdata(dev);
 	u8 data[8];
+	int ret;
  
 	max8998_tm_to_data(tm, data);
  
-	return max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
+	ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
+
+	if (info->lp3974_bug_workaround)
+		msleep(2000);
+
+	return ret;
 }
  
 static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  
@@ -163,12 +171,29 @@
  
 static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
 {
-	return max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
+	int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
+
+	if (info->lp3974_bug_workaround)
+		msleep(2000);
+
+	return ret;
 }
  
 static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
 {
-	return max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0x77);
+	int ret;
+	u8 alarm0_conf = 0x77;
+
+	/* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
+	if (info->lp3974_bug_workaround)
+		alarm0_conf = 0x57;
+
+	ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
+
+	if (info->lp3974_bug_workaround)
+		msleep(2000);
+
+	return ret;
 }
  
 static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  
  
@@ -187,10 +212,13 @@
 	if (ret < 0)
 		return ret;
  
+	if (info->lp3974_bug_workaround)
+		msleep(2000);
+
 	if (alrm->enabled)
-		return max8998_rtc_start_alarm(info);
+		ret = max8998_rtc_start_alarm(info);
  
-	return 0;
+	return ret;
 }
  
 static int max8998_rtc_alarm_irq_enable(struct device *dev,
@@ -224,6 +252,7 @@
 static int __devinit max8998_rtc_probe(struct platform_device *pdev)
 {
 	struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
+	struct max8998_platform_data *pdata = dev_get_platdata(max8998->dev);
 	struct max8998_rtc_info *info;
 	int ret;
  
  
@@ -249,10 +278,18 @@
  
 	ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
 			"rtc-alarm0", info);
+
 	if (ret < 0)
 		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 			info->irq, ret);
  
+	dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
+	if (pdata->rtc_delay) {
+		info->lp3974_bug_workaround = true;
+		dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
+				" RTC updates will be extremely slow.\n");
+	}
+
 	return 0;
  
 out_rtc:
@@ -273,6 +310,12 @@
 	return 0;
 }
  
+static const struct platform_device_id max8998_rtc_id[] = {
+	{ "max8998-rtc", TYPE_MAX8998 },
+	{ "lp3974-rtc", TYPE_LP3974 },
+	{ }
+};
+
 static struct platform_driver max8998_rtc_driver = {
 	.driver		= {
 		.name	= "max8998-rtc",
@@ -280,6 +323,7 @@
 	},
 	.probe		= max8998_rtc_probe,
 	.remove		= __devexit_p(max8998_rtc_remove),
+	.id_table	= max8998_rtc_id,
 };
  
 static int __init max8998_rtc_init(void)
@@ -76,6 +76,9 @@
  * @buck1_set1: BUCK1 gpio pin 1 to set output voltage
  * @buck1_set2: BUCK1 gpio pin 2 to set output voltage
  * @buck2_set3: BUCK2 gpio pin to set output voltage
+ * @wakeup: Allow to wake up from suspend
+ * @rtc_delay: LP3974 RTC chip bug that requires delay after a register
+ * write before reading it.
  */
 struct max8998_platform_data {
 	struct max8998_regulator_data	*regulators;
@@ -89,6 +92,7 @@
 	int				buck1_set2;
 	int				buck2_set3;
 	bool				wakeup;
+	bool				rtc_delay;
 };
  
 #endif /*  __LINUX_MFD_MAX8998_H */
...	...	@@ -42,6 +42,14 @@
42	42	},
43	43	};
44	44
	45	+static struct mfd_cell lp3974_devs[] = {
	46	+ {
	47	+ .name = "lp3974-pmic",
	48	+ }, {
	49	+ .name = "lp3974-rtc",
	50	+ },
	51	+};
	52	+
45	53	int max8998_read_reg(struct i2c_client i2c, u8 reg, u8 dest)
46	54	{
47	55	struct max8998_dev *max8998 = i2c_get_clientdata(i2c);
48	56
...	...	@@ -146,10 +154,22 @@
146	154
147	155	max8998_irq_init(max8998);
148	156
149		- ret = mfd_add_devices(max8998->dev, -1,
150		- max8998_devs, ARRAY_SIZE(max8998_devs),
151		- NULL, 0);
152	157	pm_runtime_set_active(max8998->dev);
	158	+
	159	+ switch (id->driver_data) {
	160	+ case TYPE_LP3974:
	161	+ ret = mfd_add_devices(max8998->dev, -1,
	162	+ lp3974_devs, ARRAY_SIZE(lp3974_devs),
	163	+ NULL, 0);
	164	+ break;
	165	+ case TYPE_MAX8998:
	166	+ ret = mfd_add_devices(max8998->dev, -1,
	167	+ max8998_devs, ARRAY_SIZE(max8998_devs),
	168	+ NULL, 0);
	169	+ break;
	170	+ default:
	171	+ ret = -EINVAL;
	172	+ }
153	173
154	174	if (ret < 0)
155	175	goto err;
...	...	@@ -835,6 +835,12 @@
835	835	return 0;
836	836	}
837	837
	838	+static const struct platform_device_id max8998_pmic_id[] = {
	839	+ { "max8998-pmic", TYPE_MAX8998 },
	840	+ { "lp3974-pmic", TYPE_LP3974 },
	841	+ { }
	842	+};
	843	+
838	844	static struct platform_driver max8998_pmic_driver = {
839	845	.driver = {
840	846	.name = "max8998-pmic",
...	...	@@ -842,6 +848,7 @@
842	848	},
843	849	.probe = max8998_pmic_probe,
844	850	.remove = __devexit_p(max8998_pmic_remove),
	851	+ .id_table = max8998_pmic_id,
845	852	};
846	853
847	854	static int __init max8998_pmic_init(void)
...	...	@@ -20,6 +20,7 @@
20	20	#include <linux/platform_device.h>
21	21	#include <linux/mfd/max8998.h>
22	22	#include <linux/mfd/max8998-private.h>
	23	+#include <linux/delay.h>
23	24
24	25	#define MAX8998_RTC_SEC 0x00
25	26	#define MAX8998_RTC_MIN 0x01
...	...	@@ -73,6 +74,7 @@
73	74	struct i2c_client *rtc;
74	75	struct rtc_device *rtc_dev;
75	76	int irq;
	77	+ bool lp3974_bug_workaround;
76	78	};
77	79
78	80	static void max8998_data_to_tm(u8 data, struct rtc_time tm)
79	81
...	...	@@ -124,10 +126,16 @@
124	126	{
125	127	struct max8998_rtc_info *info = dev_get_drvdata(dev);
126	128	u8 data[8];
	129	+ int ret;
127	130
128	131	max8998_tm_to_data(tm, data);
129	132
130		- return max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
	133	+ ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
	134	+
	135	+ if (info->lp3974_bug_workaround)
	136	+ msleep(2000);
	137	+
	138	+ return ret;
131	139	}
132	140
133	141	static int max8998_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
134	142
...	...	@@ -163,12 +171,29 @@
163	171
164	172	static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
165	173	{
166		- return max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
	174	+ int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
	175	+
	176	+ if (info->lp3974_bug_workaround)
	177	+ msleep(2000);
	178	+
	179	+ return ret;
167	180	}
168	181
169	182	static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
170	183	{
171		- return max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0x77);
	184	+ int ret;
	185	+ u8 alarm0_conf = 0x77;
	186	+
	187	+ /* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
	188	+ if (info->lp3974_bug_workaround)
	189	+ alarm0_conf = 0x57;
	190	+
	191	+ ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
	192	+
	193	+ if (info->lp3974_bug_workaround)
	194	+ msleep(2000);
	195	+
	196	+ return ret;
172	197	}
173	198
174	199	static int max8998_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
175	200
176	201
...	...	@@ -187,10 +212,13 @@
187	212	if (ret < 0)
188	213	return ret;
189	214
	215	+ if (info->lp3974_bug_workaround)
	216	+ msleep(2000);
	217	+
190	218	if (alrm->enabled)
191		- return max8998_rtc_start_alarm(info);
	219	+ ret = max8998_rtc_start_alarm(info);
192	220
193		- return 0;
	221	+ return ret;
194	222	}
195	223
196	224	static int max8998_rtc_alarm_irq_enable(struct device *dev,
...	...	@@ -224,6 +252,7 @@
224	252	static int __devinit max8998_rtc_probe(struct platform_device *pdev)
225	253	{
226	254	struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
	255	+ struct max8998_platform_data *pdata = dev_get_platdata(max8998->dev);
227	256	struct max8998_rtc_info *info;
228	257	int ret;
229	258
230	259
...	...	@@ -249,10 +278,18 @@
249	278
250	279	ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
251	280	"rtc-alarm0", info);
	281	+
252	282	if (ret < 0)
253	283	dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
254	284	info->irq, ret);
255	285
	286	+ dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
	287	+ if (pdata->rtc_delay) {
	288	+ info->lp3974_bug_workaround = true;
	289	+ dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
	290	+ " RTC updates will be extremely slow.\n");
	291	+ }
	292	+
256	293	return 0;
257	294
258	295	out_rtc:
...	...	@@ -273,6 +310,12 @@
273	310	return 0;
274	311	}
275	312
	313	+static const struct platform_device_id max8998_rtc_id[] = {
	314	+ { "max8998-rtc", TYPE_MAX8998 },
	315	+ { "lp3974-rtc", TYPE_LP3974 },
	316	+ { }
	317	+};
	318	+
276	319	static struct platform_driver max8998_rtc_driver = {
277	320	.driver = {
278	321	.name = "max8998-rtc",
...	...	@@ -280,6 +323,7 @@
280	323	},
281	324	.probe = max8998_rtc_probe,
282	325	.remove = __devexit_p(max8998_rtc_remove),
	326	+ .id_table = max8998_rtc_id,
283	327	};
284	328
285	329	static int __init max8998_rtc_init(void)
...	...	@@ -76,6 +76,9 @@
76	76	* @buck1_set1: BUCK1 gpio pin 1 to set output voltage
77	77	* @buck1_set2: BUCK1 gpio pin 2 to set output voltage
78	78	* @buck2_set3: BUCK2 gpio pin to set output voltage
	79	+ * @wakeup: Allow to wake up from suspend
	80	+ * @rtc_delay: LP3974 RTC chip bug that requires delay after a register
	81	+ * write before reading it.
79	82	*/
80	83	struct max8998_platform_data {
81	84	struct max8998_regulator_data *regulators;
...	...	@@ -89,6 +92,7 @@
89	92	int buck1_set2;
90	93	int buck2_set3;
91	94	bool wakeup;
	95	+ bool rtc_delay;
92	96	};
93	97
94	98	#endif /* __LINUX_MFD_MAX8998_H */