diff options
author | Thierry Reding <thierry.reding@gmail.com> | 2013-12-16 21:42:28 +0100 |
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committer | Stephen Warren <swarren@nvidia.com> | 2013-12-16 14:03:09 -0700 |
commit | 9d4450ae87398e248e8700e3507748e0d1751e25 (patch) | |
tree | eef26d8d35fe258e6b67531bcc38ec98a327be4c /arch | |
parent | c537376cbbbfea2b741b39ad37d5b44104b66e56 (diff) | |
download | linux-9d4450ae87398e248e8700e3507748e0d1751e25.tar.bz2 |
ARM: tegra: Add IO rail support
Add tegra_io_rail_power_off() and tegra_io_rail_power_on() functions to
put IO rails into or out of deep powerdown mode, respectively.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm/mach-tegra/powergate.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/powergate.c b/arch/arm/mach-tegra/powergate.c index 0026fb6c984b..3d0c537d9b94 100644 --- a/arch/arm/mach-tegra/powergate.c +++ b/arch/arm/mach-tegra/powergate.c @@ -34,6 +34,10 @@ #include "fuse.h" #include "iomap.h" +#define DPD_SAMPLE 0x020 +#define DPD_SAMPLE_ENABLE (1 << 0) +#define DPD_SAMPLE_DISABLE (0 << 0) + #define PWRGATE_TOGGLE 0x30 #define PWRGATE_TOGGLE_START (1 << 8) @@ -41,6 +45,17 @@ #define PWRGATE_STATUS 0x38 +#define IO_DPD_REQ 0x1b8 +#define IO_DPD_REQ_CODE_IDLE (0 << 30) +#define IO_DPD_REQ_CODE_OFF (1 << 30) +#define IO_DPD_REQ_CODE_ON (2 << 30) +#define IO_DPD_REQ_CODE_MASK (3 << 30) + +#define IO_DPD_STATUS 0x1bc +#define IO_DPD2_REQ 0x1c0 +#define IO_DPD2_STATUS 0x1c4 +#define SEL_DPD_TIM 0x1c8 + #define GPU_RG_CNTRL 0x2d4 static int tegra_num_powerdomains; @@ -379,3 +394,120 @@ int __init tegra_powergate_debugfs_init(void) } #endif + +static int tegra_io_rail_prepare(int id, unsigned long *request, + unsigned long *status, unsigned int *bit) +{ + unsigned long rate, value; + struct clk *clk; + + *bit = id % 32; + + /* + * There are two sets of 30 bits to select IO rails, but bits 30 and + * 31 are control bits rather than IO rail selection bits. + */ + if (id > 63 || *bit == 30 || *bit == 31) + return -EINVAL; + + if (id < 32) { + *status = IO_DPD_STATUS; + *request = IO_DPD_REQ; + } else { + *status = IO_DPD2_STATUS; + *request = IO_DPD2_REQ; + } + + clk = clk_get_sys(NULL, "pclk"); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + rate = clk_get_rate(clk); + clk_put(clk); + + pmc_write(DPD_SAMPLE_ENABLE, DPD_SAMPLE); + + /* must be at least 200 ns, in APB (PCLK) clock cycles */ + value = DIV_ROUND_UP(1000000000, rate); + value = DIV_ROUND_UP(200, value); + pmc_write(value, SEL_DPD_TIM); + + return 0; +} + +static int tegra_io_rail_poll(unsigned long offset, unsigned long mask, + unsigned long val, unsigned long timeout) +{ + unsigned long value; + + timeout = jiffies + msecs_to_jiffies(timeout); + + while (time_after(timeout, jiffies)) { + value = pmc_read(offset); + if ((value & mask) == val) + return 0; + + usleep_range(250, 1000); + } + + return -ETIMEDOUT; +} + +static void tegra_io_rail_unprepare(void) +{ + pmc_write(DPD_SAMPLE_DISABLE, DPD_SAMPLE); +} + +int tegra_io_rail_power_on(int id) +{ + unsigned long request, status, value; + unsigned int bit, mask; + int err; + + err = tegra_io_rail_prepare(id, &request, &status, &bit); + if (err < 0) + return err; + + mask = 1 << bit; + + value = pmc_read(request); + value |= mask; + value &= ~IO_DPD_REQ_CODE_MASK; + value |= IO_DPD_REQ_CODE_OFF; + pmc_write(value, request); + + err = tegra_io_rail_poll(status, mask, 0, 250); + if (err < 0) + return err; + + tegra_io_rail_unprepare(); + + return 0; +} + +int tegra_io_rail_power_off(int id) +{ + unsigned long request, status, value; + unsigned int bit, mask; + int err; + + err = tegra_io_rail_prepare(id, &request, &status, &bit); + if (err < 0) + return err; + + mask = 1 << bit; + + value = pmc_read(request); + value |= mask; + value &= ~IO_DPD_REQ_CODE_MASK; + value |= IO_DPD_REQ_CODE_ON; + pmc_write(value, request); + + err = tegra_io_rail_poll(status, mask, mask, 250); + if (err < 0) + return err; + + tegra_io_rail_unprepare(); + + return 0; +} |