1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/bitops.h>
  3#include <linux/interrupt.h>
  4#include <linux/kernel.h>
  5#include <linux/module.h>
  6#include <linux/of.h>
  7#include <linux/property.h>
  8#include <linux/platform_device.h>
  9#include <linux/regmap.h>
 10#include <linux/watchdog.h>
 11
 12#define PON_INT_RT_STS			0x10
 13#define PMIC_WD_BARK_STS_BIT		BIT(6)
 14
 15#define PON_PMIC_WD_RESET_S1_TIMER	0x54
 16#define PON_PMIC_WD_RESET_S2_TIMER	0x55
 17
 18#define PON_PMIC_WD_RESET_S2_CTL	0x56
 19#define RESET_TYPE_WARM			0x01
 20#define RESET_TYPE_SHUTDOWN		0x04
 21#define RESET_TYPE_HARD			0x07
 22
 23#define PON_PMIC_WD_RESET_S2_CTL2	0x57
 24#define S2_RESET_EN_BIT			BIT(7)
 25
 26#define PON_PMIC_WD_RESET_PET		0x58
 27#define WATCHDOG_PET_BIT		BIT(0)
 28
 29#define PM8916_WDT_DEFAULT_TIMEOUT	32
 30#define PM8916_WDT_MIN_TIMEOUT		1
 31#define PM8916_WDT_MAX_TIMEOUT		127
 32
 33struct pm8916_wdt {
 34	struct regmap *regmap;
 35	struct watchdog_device wdev;
 36	u32 baseaddr;
 37};
 38
 39static int pm8916_wdt_start(struct watchdog_device *wdev)
 40{
 41	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
 42
 43	return regmap_update_bits(wdt->regmap,
 44				  wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
 45				  S2_RESET_EN_BIT, S2_RESET_EN_BIT);
 46}
 47
 48static int pm8916_wdt_stop(struct watchdog_device *wdev)
 49{
 50	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
 51
 52	return regmap_update_bits(wdt->regmap,
 53				  wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
 54				  S2_RESET_EN_BIT, 0);
 55}
 56
 57static int pm8916_wdt_ping(struct watchdog_device *wdev)
 58{
 59	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
 60
 61	return regmap_update_bits(wdt->regmap,
 62				  wdt->baseaddr + PON_PMIC_WD_RESET_PET,
 63				  WATCHDOG_PET_BIT, WATCHDOG_PET_BIT);
 64}
 65
 66static int pm8916_wdt_configure_timers(struct watchdog_device *wdev)
 67{
 68	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
 69	int err;
 70
 71	err = regmap_write(wdt->regmap,
 72			   wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
 73			   wdev->timeout - wdev->pretimeout);
 74	if (err)
 75		return err;
 76
 77	return regmap_write(wdt->regmap,
 78			    wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
 79			    wdev->pretimeout);
 80}
 81
 82static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
 83				  unsigned int timeout)
 84{
 85	wdev->timeout = timeout;
 86
 87	return pm8916_wdt_configure_timers(wdev);
 88}
 89
 90static int pm8916_wdt_set_pretimeout(struct watchdog_device *wdev,
 91				     unsigned int pretimeout)
 92{
 93	wdev->pretimeout = pretimeout;
 94
 95	return pm8916_wdt_configure_timers(wdev);
 96}
 97
 98static irqreturn_t pm8916_wdt_isr(int irq, void *arg)
 99{
100	struct pm8916_wdt *wdt = arg;
101	int err, sts;
102
103	err = regmap_read(wdt->regmap, wdt->baseaddr + PON_INT_RT_STS, &sts);
104	if (err)
105		return IRQ_HANDLED;
106
107	if (sts & PMIC_WD_BARK_STS_BIT)
108		watchdog_notify_pretimeout(&wdt->wdev);
109
110	return IRQ_HANDLED;
111}
112
113static const struct watchdog_info pm8916_wdt_ident = {
114	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
115	.identity = "QCOM PM8916 PON WDT",
116};
117
118static const struct watchdog_info pm8916_wdt_pt_ident = {
119	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
120		   WDIOF_PRETIMEOUT,
121	.identity = "QCOM PM8916 PON WDT",
122};
123
124static const struct watchdog_ops pm8916_wdt_ops = {
125	.owner = THIS_MODULE,
126	.start = pm8916_wdt_start,
127	.stop = pm8916_wdt_stop,
128	.ping = pm8916_wdt_ping,
129	.set_timeout = pm8916_wdt_set_timeout,
130	.set_pretimeout = pm8916_wdt_set_pretimeout,
131};
132
133static int pm8916_wdt_probe(struct platform_device *pdev)
134{
135	struct device *dev = &pdev->dev;
136	struct pm8916_wdt *wdt;
137	struct device *parent;
138	int err, irq;
139
140	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
141	if (!wdt)
142		return -ENOMEM;
143
144	parent = dev->parent;
145
146	/*
147	 * The pm8916-pon-wdt is a child of the pon device, which is a child
148	 * of the pm8916 mfd device. We want access to the pm8916 registers.
149	 * Retrieve regmap from pm8916 (parent->parent) and base address
150	 * from pm8916-pon (pon).
151	 */
152	wdt->regmap = dev_get_regmap(parent->parent, NULL);
153	if (!wdt->regmap) {
154		dev_err(dev, "failed to locate regmap\n");
155		return -ENODEV;
156	}
157
158	err = device_property_read_u32(parent, "reg", &wdt->baseaddr);
159	if (err) {
160		dev_err(dev, "failed to get pm8916-pon address\n");
161		return err;
162	}
163
164	irq = platform_get_irq(pdev, 0);
165	if (irq > 0) {
166		err = devm_request_irq(dev, irq, pm8916_wdt_isr, 0,
167				       "pm8916_wdt", wdt);
168		if (err)
169			return err;
170
171		wdt->wdev.info = &pm8916_wdt_pt_ident;
172	} else {
173		if (irq == -EPROBE_DEFER)
174			return -EPROBE_DEFER;
175
176		wdt->wdev.info = &pm8916_wdt_ident;
177	}
178
179	/* Configure watchdog to hard-reset mode */
180	err = regmap_write(wdt->regmap,
181			   wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL,
182			   RESET_TYPE_HARD);
183	if (err) {
184		dev_err(dev, "failed configure watchdog\n");
185		return err;
186	}
187
188	wdt->wdev.ops = &pm8916_wdt_ops,
189	wdt->wdev.parent = dev;
190	wdt->wdev.min_timeout = PM8916_WDT_MIN_TIMEOUT;
191	wdt->wdev.max_timeout = PM8916_WDT_MAX_TIMEOUT;
192	wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
193	wdt->wdev.pretimeout = 0;
194	watchdog_set_drvdata(&wdt->wdev, wdt);
195	platform_set_drvdata(pdev, wdt);
196
197	watchdog_init_timeout(&wdt->wdev, 0, dev);
198	pm8916_wdt_configure_timers(&wdt->wdev);
199
200	return devm_watchdog_register_device(dev, &wdt->wdev);
201}
202
203static int __maybe_unused pm8916_wdt_suspend(struct device *dev)
204{
205	struct pm8916_wdt *wdt = dev_get_drvdata(dev);
206
207	if (watchdog_active(&wdt->wdev))
208		return pm8916_wdt_stop(&wdt->wdev);
209
210	return 0;
211}
212
213static int __maybe_unused pm8916_wdt_resume(struct device *dev)
214{
215	struct pm8916_wdt *wdt = dev_get_drvdata(dev);
216
217	if (watchdog_active(&wdt->wdev))
218		return pm8916_wdt_start(&wdt->wdev);
219
220	return 0;
221}
222
223static SIMPLE_DEV_PM_OPS(pm8916_wdt_pm_ops, pm8916_wdt_suspend,
224			 pm8916_wdt_resume);
225
226static const struct of_device_id pm8916_wdt_id_table[] = {
227	{ .compatible = "qcom,pm8916-wdt" },
228	{ }
229};
230MODULE_DEVICE_TABLE(of, pm8916_wdt_id_table);
231
232static struct platform_driver pm8916_wdt_driver = {
233	.probe = pm8916_wdt_probe,
234	.driver = {
235		.name = "pm8916-wdt",
236		.of_match_table = of_match_ptr(pm8916_wdt_id_table),
237		.pm = &pm8916_wdt_pm_ops,
238	},
239};
240module_platform_driver(pm8916_wdt_driver);
241
242MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
243MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
244MODULE_LICENSE("GPL v2");