diff options
Diffstat (limited to 'drivers/clk/qcom/gdsc.c')
| -rw-r--r-- | drivers/clk/qcom/gdsc.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c new file mode 100644 index 0000000..469b4c4 --- /dev/null +++ b/drivers/clk/qcom/gdsc.c @@ -0,0 +1,171 @@ +/* + * Copyright (c) 2015, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/pm_domain.h> +#include <linux/regmap.h> +#include <linux/slab.h> +#include "gdsc.h" + +#define PWR_ON_MASK BIT(31) +#define EN_REST_WAIT_MASK GENMASK_ULL(23, 20) +#define EN_FEW_WAIT_MASK GENMASK_ULL(19, 16) +#define CLK_DIS_WAIT_MASK GENMASK_ULL(15, 12) +#define SW_OVERRIDE_MASK BIT(2) +#define HW_CONTROL_MASK BIT(1) +#define SW_COLLAPSE_MASK BIT(0) + +/* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */ +#define EN_REST_WAIT_VAL (0x2 << 20) +#define EN_FEW_WAIT_VAL (0x8 << 16) +#define CLK_DIS_WAIT_VAL (0x2 << 12) + +#define TIMEOUT_US 100 + +#define domain_to_gdsc(domain) container_of(domain, struct gdsc, pd) + +static int gdsc_is_enabled(struct gdsc *sc) +{ + u32 val; + int ret; + + ret = regmap_read(sc->regmap, sc->gdscr, &val); + if (ret) + return ret; + + return !!(val & PWR_ON_MASK); +} + +static int gdsc_toggle_logic(struct gdsc *sc, bool en) +{ + int ret; + u32 val = en ? 0 : SW_COLLAPSE_MASK; + u32 check = en ? PWR_ON_MASK : 0; + unsigned long timeout; + + ret = regmap_update_bits(sc->regmap, sc->gdscr, SW_COLLAPSE_MASK, val); + if (ret) + return ret; + + timeout = jiffies + usecs_to_jiffies(TIMEOUT_US); + do { + ret = regmap_read(sc->regmap, sc->gdscr, &val); + if (ret) + return ret; + + if ((val & PWR_ON_MASK) == check) + return 0; + } while (time_before(jiffies, timeout)); + + ret = regmap_read(sc->regmap, sc->gdscr, &val); + if (ret) + return ret; + + if ((val & PWR_ON_MASK) == check) + return 0; + + return -ETIMEDOUT; +} + +static int gdsc_enable(struct generic_pm_domain *domain) +{ + struct gdsc *sc = domain_to_gdsc(domain); + int ret; + + ret = gdsc_toggle_logic(sc, true); + if (ret) + return ret; + /* + * If clocks to this power domain were already on, they will take an + * additional 4 clock cycles to re-enable after the power domain is + * enabled. Delay to account for this. A delay is also needed to ensure + * clocks are not enabled within 400ns of enabling power to the + * memories. + */ + udelay(1); + + return 0; +} + +static int gdsc_disable(struct generic_pm_domain *domain) +{ + struct gdsc *sc = domain_to_gdsc(domain); + + return gdsc_toggle_logic(sc, false); +} + +static int gdsc_init(struct gdsc *sc) +{ + u32 mask, val; + int on, ret; + + /* + * Disable HW trigger: collapse/restore occur based on registers writes. + * Disable SW override: Use hardware state-machine for sequencing. + * Configure wait time between states. + */ + mask = HW_CONTROL_MASK | SW_OVERRIDE_MASK | + EN_REST_WAIT_MASK | EN_FEW_WAIT_MASK | CLK_DIS_WAIT_MASK; + val = EN_REST_WAIT_VAL | EN_FEW_WAIT_VAL | CLK_DIS_WAIT_VAL; + ret = regmap_update_bits(sc->regmap, sc->gdscr, mask, val); + if (ret) + return ret; + + on = gdsc_is_enabled(sc); + if (on < 0) + return on; + + sc->pd.power_off = gdsc_disable; + sc->pd.power_on = gdsc_enable; + pm_genpd_init(&sc->pd, NULL, !on); + + return 0; +} + +int gdsc_register(struct device *dev, struct gdsc **scs, size_t num, + struct regmap *regmap) +{ + int i, ret; + struct genpd_onecell_data *data; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->domains = devm_kcalloc(dev, num, sizeof(*data->domains), + GFP_KERNEL); + if (!data->domains) + return -ENOMEM; + + data->num_domains = num; + for (i = 0; i < num; i++) { + if (!scs[i]) + continue; + scs[i]->regmap = regmap; + ret = gdsc_init(scs[i]); + if (ret) + return ret; + data->domains[i] = &scs[i]->pd; + } + + return of_genpd_add_provider_onecell(dev->of_node, data); +} + +void gdsc_unregister(struct device *dev) +{ + of_genpd_del_provider(dev->of_node); +} |