2 * Atmel SAMA5D2-Compatible Shutdown Controller (SHDWC) driver.
3 * Found on some SoCs as the sama5d2 (obviously).
5 * Copyright (C) 2015 Atmel Corporation,
6 * Nicolas Ferre <nicolas.ferre@atmel.com>
8 * Evolved from driver at91-poweroff.c.
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
15 * - addition to status of other wake-up inputs [1 - 15]
16 * - Analog Comparator wake-up alarm
17 * - Serial RX wake-up alarm
18 * - low power debouncer
21 #include <linux/clk.h>
23 #include <linux/module.h>
25 #include <linux/of_address.h>
26 #include <linux/platform_device.h>
27 #include <linux/printk.h>
29 #include <soc/at91/at91sam9_ddrsdr.h>
31 #define SLOW_CLOCK_FREQ 32768
33 #define AT91_SHDW_CR 0x00 /* Shut Down Control Register */
34 #define AT91_SHDW_SHDW BIT(0) /* Shut Down command */
35 #define AT91_SHDW_KEY (0xa5UL << 24) /* KEY Password */
37 #define AT91_SHDW_MR 0x04 /* Shut Down Mode Register */
38 #define AT91_SHDW_WKUPDBC_SHIFT 24
39 #define AT91_SHDW_WKUPDBC_MASK GENMASK(26, 24)
40 #define AT91_SHDW_WKUPDBC(x) (((x) << AT91_SHDW_WKUPDBC_SHIFT) \
41 & AT91_SHDW_WKUPDBC_MASK)
43 #define AT91_SHDW_SR 0x08 /* Shut Down Status Register */
44 #define AT91_SHDW_WKUPIS_SHIFT 16
45 #define AT91_SHDW_WKUPIS_MASK GENMASK(31, 16)
46 #define AT91_SHDW_WKUPIS(x) ((1 << (x)) << AT91_SHDW_WKUPIS_SHIFT \
47 & AT91_SHDW_WKUPIS_MASK)
49 #define AT91_SHDW_WUIR 0x0c /* Shutdown Wake-up Inputs Register */
50 #define AT91_SHDW_WKUPEN_MASK GENMASK(15, 0)
51 #define AT91_SHDW_WKUPEN(x) ((1 << (x)) & AT91_SHDW_WKUPEN_MASK)
52 #define AT91_SHDW_WKUPT_SHIFT 16
53 #define AT91_SHDW_WKUPT_MASK GENMASK(31, 16)
54 #define AT91_SHDW_WKUPT(x) ((1 << (x)) << AT91_SHDW_WKUPT_SHIFT \
55 & AT91_SHDW_WKUPT_MASK)
57 #define SHDW_WK_PIN(reg, cfg) ((reg) & AT91_SHDW_WKUPIS((cfg)->wkup_pin_input))
58 #define SHDW_RTCWK(reg, cfg) (((reg) >> ((cfg)->sr_rtcwk_shift)) & 0x1)
59 #define SHDW_RTCWKEN(cfg) (1 << ((cfg)->mr_rtcwk_shift))
61 #define DBC_PERIOD_US(x) DIV_ROUND_UP_ULL((1000000 * (x)), \
71 const struct shdwc_config *cfg;
72 void __iomem *at91_shdwc_base;
76 * Hold configuration here, cannot be more than one instance of the driver
77 * since pm_power_off itself is global.
79 static struct shdwc *at91_shdwc;
80 static struct clk *sclk;
81 static void __iomem *mpddrc_base;
83 static const unsigned long long sdwc_dbc_period[] = {
84 0, 3, 32, 512, 4096, 32768,
87 static void __init at91_wakeup_status(struct platform_device *pdev)
89 struct shdwc *shdw = platform_get_drvdata(pdev);
91 char *reason = "unknown";
93 reg = readl(shdw->at91_shdwc_base + AT91_SHDW_SR);
95 dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);
97 /* Simple power-on, just bail out */
101 if (SHDW_WK_PIN(reg, shdw->cfg))
103 else if (SHDW_RTCWK(reg, shdw->cfg))
106 pr_info("AT91: Wake-Up source: %s\n", reason);
109 static void at91_poweroff(void)
111 writel(AT91_SHDW_KEY | AT91_SHDW_SHDW,
112 at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);
115 static void at91_lpddr_poweroff(void)
118 /* Align to cache lines */
121 /* Ensure AT91_SHDW_CR is in the TLB by reading it */
122 " ldr r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
124 /* Power down SDRAM0 */
125 " str %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
127 " str %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
132 "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
133 "r" (at91_shdwc->at91_shdwc_base),
134 "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW)
138 static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
142 int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
143 unsigned long long period_us;
144 unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);
146 if (in_period_us > max_period_us) {
148 "debouncer period %u too big, reduced to %llu us\n",
149 in_period_us, max_period_us);
153 for (i = max_idx - 1; i > 0; i--) {
154 period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
155 dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
156 __func__, i, period_us);
157 if (in_period_us > period_us)
164 static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
165 struct device_node *np)
167 struct device_node *cnp;
172 for_each_child_of_node(np, cnp) {
173 if (of_property_read_u32(cnp, "reg", &wk_input)) {
174 dev_warn(&pdev->dev, "reg property is missing for %pOF\n",
179 wk_input_mask = 1 << wk_input;
180 if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
182 "wake-up input %d out of bounds ignore\n",
186 wuir |= wk_input_mask;
188 if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
189 wuir |= AT91_SHDW_WKUPT(wk_input);
191 dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
192 __func__, wk_input, wuir);
198 static void at91_shdwc_dt_configure(struct platform_device *pdev)
200 struct shdwc *shdw = platform_get_drvdata(pdev);
201 struct device_node *np = pdev->dev.of_node;
202 u32 mode = 0, tmp, input;
205 dev_err(&pdev->dev, "device node not found\n");
209 if (!of_property_read_u32(np, "debounce-delay-us", &tmp))
210 mode |= AT91_SHDW_WKUPDBC(at91_shdwc_debouncer_value(pdev, tmp));
212 if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
213 mode |= SHDW_RTCWKEN(shdw->cfg);
215 dev_dbg(&pdev->dev, "%s: mode = %#x\n", __func__, mode);
216 writel(mode, shdw->at91_shdwc_base + AT91_SHDW_MR);
218 input = at91_shdwc_get_wakeup_input(pdev, np);
219 writel(input, shdw->at91_shdwc_base + AT91_SHDW_WUIR);
222 static const struct shdwc_config sama5d2_shdwc_config = {
224 .mr_rtcwk_shift = 17,
228 static const struct of_device_id at91_shdwc_of_match[] = {
230 .compatible = "atmel,sama5d2-shdwc",
231 .data = &sama5d2_shdwc_config,
236 MODULE_DEVICE_TABLE(of, at91_shdwc_of_match);
238 static int __init at91_shdwc_probe(struct platform_device *pdev)
240 struct resource *res;
241 const struct of_device_id *match;
242 struct device_node *np;
246 if (!pdev->dev.of_node)
252 at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
256 platform_set_drvdata(pdev, at91_shdwc);
258 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
259 at91_shdwc->at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
260 if (IS_ERR(at91_shdwc->at91_shdwc_base)) {
261 dev_err(&pdev->dev, "Could not map reset controller address\n");
262 return PTR_ERR(at91_shdwc->at91_shdwc_base);
265 match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
266 at91_shdwc->cfg = match->data;
268 sclk = devm_clk_get(&pdev->dev, NULL);
270 return PTR_ERR(sclk);
272 ret = clk_prepare_enable(sclk);
274 dev_err(&pdev->dev, "Could not enable slow clock\n");
278 at91_wakeup_status(pdev);
280 at91_shdwc_dt_configure(pdev);
282 pm_power_off = at91_poweroff;
284 np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
288 mpddrc_base = of_iomap(np, 0);
294 ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD;
295 if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) ||
296 (ddr_type == AT91_DDRSDRC_MD_LPDDR3))
297 pm_power_off = at91_lpddr_poweroff;
299 iounmap(mpddrc_base);
304 static int __exit at91_shdwc_remove(struct platform_device *pdev)
306 struct shdwc *shdw = platform_get_drvdata(pdev);
308 if (pm_power_off == at91_poweroff ||
309 pm_power_off == at91_lpddr_poweroff)
312 /* Reset values to disable wake-up features */
313 writel(0, shdw->at91_shdwc_base + AT91_SHDW_MR);
314 writel(0, shdw->at91_shdwc_base + AT91_SHDW_WUIR);
316 clk_disable_unprepare(sclk);
321 static struct platform_driver at91_shdwc_driver = {
322 .remove = __exit_p(at91_shdwc_remove),
324 .name = "at91-shdwc",
325 .of_match_table = at91_shdwc_of_match,
328 module_platform_driver_probe(at91_shdwc_driver, at91_shdwc_probe);
330 MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
331 MODULE_DESCRIPTION("Atmel shutdown controller driver");
332 MODULE_LICENSE("GPL v2");