[2/6] soc: ti: omap-prm: Add basic power domain support

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -7,6 +7,7 @@  config ARCH_OMAP2
 	depends on ARCH_MULTI_V6
 	select ARCH_OMAP2PLUS
 	select CPU_V6
+	select PM_GENERIC_DOMAINS if PM
 	select SOC_HAS_OMAP2_SDRC
 
 config ARCH_OMAP3
diff --git a/drivers/soc/ti/omap_prm.c b/drivers/soc/ti/omap_prm.c
--- a/drivers/soc/ti/omap_prm.c
+++ b/drivers/soc/ti/omap_prm.c
@@ -10,14 +10,39 @@ 
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_domain.h>
 #include <linux/reset-controller.h>
 #include <linux/delay.h>
 
 #include <linux/platform_data/ti-prm.h>
 
+enum omap_prm_domain_mode {
+	OMAP_PRMD_OFF,
+	OMAP_PRMD_RETENTION,
+	OMAP_PRMD_ON_INACTIVE,
+	OMAP_PRMD_ON_ACTIVE,
+};
+
+struct omap_prm_domain_map {
+	unsigned int usable_modes;	/* Mask of hardware supported modes */
+	unsigned long statechange:1;	/* Optional low-power state change */
+	unsigned long logicretstate:1;	/* Optional logic off mode */
+};
+
+struct omap_prm_domain {
+	struct device *dev;
+	struct omap_prm *prm;
+	struct generic_pm_domain pd;
+	u16 pwrstctrl;
+	u16 pwrstst;
+	const struct omap_prm_domain_map *cap;
+	u32 pwrstctrl_saved;
+};
+
 struct omap_rst_map {
 	s8 rst;
 	s8 st;
@@ -27,6 +52,9 @@  struct omap_prm_data {
 	u32 base;
 	const char *name;
 	const char *clkdm_name;
+	u16 pwrstctrl;
+	u16 pwrstst;
+	const struct omap_prm_domain_map *dmap;
 	u16 rstctrl;
 	u16 rstst;
 	const struct omap_rst_map *rstmap;
@@ -36,6 +64,7 @@  struct omap_prm_data {
 struct omap_prm {
 	const struct omap_prm_data *data;
 	void __iomem *base;
+	struct omap_prm_domain *prmd;
 };
 
 struct omap_reset_data {
@@ -47,6 +76,7 @@  struct omap_reset_data {
 	struct device *dev;
 };
 
+#define genpd_to_prm_domain(gpd) container_of(gpd, struct omap_prm_domain, pd)
 #define to_omap_reset_data(p) container_of((p), struct omap_reset_data, rcdev)
 
 #define OMAP_MAX_RESETS		8
@@ -58,6 +88,43 @@  struct omap_reset_data {
 
 #define OMAP_PRM_HAS_RESETS	(OMAP_PRM_HAS_RSTCTRL | OMAP_PRM_HAS_RSTST)
 
+#define PRM_STATE_MAX_WAIT	10000
+#define PRM_LOGICRETSTATE	BIT(2)
+#define PRM_LOWPOWERSTATECHANGE	BIT(4)
+#define PRM_POWERSTATE_MASK	OMAP_PRMD_ON_ACTIVE
+
+#define PRM_ST_INTRANSITION	BIT(20)
+
+static const struct __maybe_unused
+omap_prm_domain_map omap_prm_all = {
+	.usable_modes = BIT(OMAP_PRMD_ON_ACTIVE) | BIT(OMAP_PRMD_ON_INACTIVE) |
+			BIT(OMAP_PRMD_RETENTION) | BIT(OMAP_PRMD_OFF),
+	.statechange = 1,
+	.logicretstate = 1,
+};
+
+static const struct __maybe_unused
+omap_prm_domain_map omap_prm_noinact = {
+	.usable_modes = BIT(OMAP_PRMD_ON_ACTIVE) | BIT(OMAP_PRMD_RETENTION) |
+			BIT(OMAP_PRMD_OFF),
+	.statechange = 1,
+	.logicretstate = 1,
+};
+
+static const struct __maybe_unused
+omap_prm_domain_map omap_prm_nooff = {
+	.usable_modes = BIT(OMAP_PRMD_ON_ACTIVE) | BIT(OMAP_PRMD_ON_INACTIVE) |
+			BIT(OMAP_PRMD_RETENTION),
+	.statechange = 1,
+	.logicretstate = 1,
+};
+
+static const struct __maybe_unused
+omap_prm_domain_map omap_prm_onoff_noauto = {
+	.usable_modes = BIT(OMAP_PRMD_ON_ACTIVE) | BIT(OMAP_PRMD_OFF),
+	.statechange = 1,
+};
+
 static const struct omap_rst_map rst_map_0[] = {
 	{ .rst = 0, .st = 0 },
 	{ .rst = -1 },
@@ -151,6 +218,183 @@  static const struct of_device_id omap_prm_id_table[] = {
 	{ },
 };
 
+#ifdef DEBUG
+static void omap_prm_domain_show_state(struct omap_prm_domain *prmd,
+				       const char *desc)
+{
+	dev_dbg(prmd->dev, "%s %s: %08x/%08x\n",
+		prmd->pd.name, desc,
+		readl_relaxed(prmd->prm->base + prmd->pwrstctrl),
+		readl_relaxed(prmd->prm->base + prmd->pwrstst));
+}
+#else
+static inline void omap_prm_domain_show_state(struct omap_prm_domain *prmd,
+					      const char *desc)
+{
+}
+#endif
+
+static int omap_prm_domain_power_on(struct generic_pm_domain *domain)
+{
+	struct omap_prm_domain *prmd;
+	int ret;
+	u32 v;
+
+	prmd = genpd_to_prm_domain(domain);
+	if (!prmd->cap)
+		return 0;
+
+	omap_prm_domain_show_state(prmd, "on: previous state");
+
+	if (prmd->pwrstctrl_saved)
+		v = prmd->pwrstctrl_saved;
+	else
+		v = readl_relaxed(prmd->prm->base + prmd->pwrstctrl);
+
+	writel_relaxed(v | OMAP_PRMD_ON_ACTIVE,
+		       prmd->prm->base + prmd->pwrstctrl);
+
+	/* wait for the transition bit to get cleared */
+	ret = readl_relaxed_poll_timeout(prmd->prm->base + prmd->pwrstst,
+					 v, !(v & PRM_ST_INTRANSITION), 1,
+					 PRM_STATE_MAX_WAIT);
+	if (ret)
+		dev_err(prmd->dev, "%s: %s timed out\n",
+			prmd->pd.name, __func__);
+
+	omap_prm_domain_show_state(prmd, "on: new state");
+
+	return ret;
+}
+
+/* No need to check for holes in the mask for the lowest mode */
+static int omap_prm_domain_find_lowest(struct omap_prm_domain *prmd)
+{
+	return __ffs(prmd->cap->usable_modes);
+}
+
+static int omap_prm_domain_power_off(struct generic_pm_domain *domain)
+{
+	struct omap_prm_domain *prmd;
+	int ret;
+	u32 v;
+
+	prmd = genpd_to_prm_domain(domain);
+	if (!prmd->cap)
+		return 0;
+
+	omap_prm_domain_show_state(prmd, "off: previous state");
+
+	v = readl_relaxed(prmd->prm->base + prmd->pwrstctrl);
+	prmd->pwrstctrl_saved = v;
+
+	v &= ~PRM_POWERSTATE_MASK;
+	v |= omap_prm_domain_find_lowest(prmd);
+
+	if (prmd->cap->statechange)
+		v |= PRM_LOWPOWERSTATECHANGE;
+	if (prmd->cap->logicretstate)
+		v &= ~PRM_LOGICRETSTATE;
+	else
+		v |= PRM_LOGICRETSTATE;
+
+	writel_relaxed(v, prmd->prm->base + prmd->pwrstctrl);
+
+	/* wait for the transition bit to get cleared */
+	ret = readl_relaxed_poll_timeout(prmd->prm->base + prmd->pwrstst,
+					 v, !(v & PRM_ST_INTRANSITION), 1,
+					 PRM_STATE_MAX_WAIT);
+	if (ret)
+		dev_warn(prmd->dev, "%s: %s timed out\n",
+			 __func__, prmd->pd.name);
+
+	omap_prm_domain_show_state(prmd, "off: new state");
+
+	return 0;
+}
+
+static int omap_prm_domain_attach_dev(struct generic_pm_domain *domain,
+				      struct device *dev)
+{
+	struct generic_pm_domain_data *genpd_data;
+	struct of_phandle_args pd_args;
+	struct omap_prm_domain *prmd;
+	struct device_node *np;
+	int ret;
+
+	prmd = genpd_to_prm_domain(domain);
+	np = dev->of_node;
+
+	ret = of_parse_phandle_with_args(np, "power-domains",
+					 "#power-domain-cells", 0, &pd_args);
+	if (ret < 0)
+		return ret;
+
+	if (pd_args.args_count != 0)
+		dev_warn(dev, "%s: unusupported #power-domain-cells: %i\n",
+			 prmd->pd.name, pd_args.args_count);
+
+	genpd_data = dev_gpd_data(dev);
+	genpd_data->data = NULL;
+
+	return 0;
+}
+
+static void omap_prm_domain_detach_dev(struct generic_pm_domain *domain,
+				       struct device *dev)
+{
+	struct generic_pm_domain_data *genpd_data;
+	struct omap_prm_domain *prmd;
+
+	prmd = genpd_to_prm_domain(domain);
+
+	genpd_data = dev_gpd_data(dev);
+	genpd_data->data = NULL;
+}
+
+static int omap_prm_domain_init(struct device *dev, struct omap_prm *prm)
+{
+	struct omap_prm_domain *prmd;
+	struct device_node *np = dev->of_node;
+	const struct omap_prm_data *data;
+	const char *name;
+	int error;
+
+	if (!of_find_property(dev->of_node, "#power-domain-cells", NULL))
+		return 0;
+
+	of_node_put(dev->of_node);
+
+	prmd = devm_kzalloc(dev, sizeof(*prmd), GFP_KERNEL);
+	if (!prmd)
+		return -ENOMEM;
+
+	data = prm->data;
+	name = devm_kasprintf(dev, GFP_KERNEL, "prm_%s",
+			      data->name);
+
+	prmd->dev = dev;
+	prmd->prm = prm;
+	prmd->cap = prmd->prm->data->dmap;
+	prmd->pwrstctrl = prmd->prm->data->pwrstctrl;
+	prmd->pwrstst = prmd->prm->data->pwrstst;
+
+	prmd->pd.name = name;
+	prmd->pd.power_on = omap_prm_domain_power_on;
+	prmd->pd.power_off = omap_prm_domain_power_off;
+	prmd->pd.attach_dev = omap_prm_domain_attach_dev;
+	prmd->pd.detach_dev = omap_prm_domain_detach_dev;
+
+	pm_genpd_init(&prmd->pd, NULL, true);
+	error = of_genpd_add_provider_simple(np, &prmd->pd);
+	if (error)
+		pm_genpd_remove(&prmd->pd);
+	else
+		prm->prmd = prmd;
+
+	return error;
+}
+
 static bool _is_valid_reset(struct omap_reset_data *reset, unsigned long id)
 {
 	if (reset->mask & BIT(id))
@@ -351,6 +595,7 @@  static int omap_prm_probe(struct platform_device *pdev)
 	const struct omap_prm_data *data;
 	struct omap_prm *prm;
 	const struct of_device_id *match;
+	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
@@ -378,7 +623,21 @@  static int omap_prm_probe(struct platform_device *pdev)
 	if (IS_ERR(prm->base))
 		return PTR_ERR(prm->base);
 
-	return omap_prm_reset_init(pdev, prm);
+	ret = omap_prm_domain_init(&pdev->dev, prm);
+	if (ret)
+		return ret;
+
+	ret = omap_prm_reset_init(pdev, prm);
+	if (ret)
+		goto err_domain;
+
+	return 0;
+
+err_domain:
+	of_genpd_del_provider(pdev->dev.of_node);
+	pm_genpd_remove(&prm->prmd->pd);
+
+	return ret;
 }
 
 static struct platform_driver omap_prm_driver = {