1 /* 2 * Tegra pulse width frequency modulator definitions 3 * 4 * Copyright (c) 2011 The Chromium OS Authors. 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 #ifndef __ASM_ARCH_TEGRA_PWM_H 10 #define __ASM_ARCH_TEGRA_PWM_H 11 12 /* This is a single PWM channel */ 13 struct pwm_ctlr { 14 uint control; /* Control register */ 15 uint reserved[3]; /* Space space */ 16 }; 17 18 #define PWM_NUM_CHANNELS 4 19 20 /* PWM_CONTROLLER_PWM_CSR_0/1/2/3_0 */ 21 #define PWM_ENABLE_SHIFT 31 22 #define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) 23 24 #define PWM_WIDTH_SHIFT 16 25 #define PWM_WIDTH_MASK (0x7FFF << PWM_WIDTH_SHIFT) 26 27 #define PWM_DIVIDER_SHIFT 0 28 #define PWM_DIVIDER_MASK (0x1FFF << PWM_DIVIDER_SHIFT) 29 30 /** 31 * Program the PWM with the given parameters. 32 * 33 * @param channel PWM channel to update 34 * @param rate Clock rate to use for PWM, or 0 to leave alone 35 * @param pulse_width high pulse width: 0=always low, 1=1/256 pulse high, 36 * n = n/256 pulse high 37 * @param freq_divider frequency divider value (1 to use rate as is) 38 */ 39 void pwm_enable(unsigned channel, int rate, int pulse_width, int freq_divider); 40 41 /** 42 * Request a pwm channel as referenced by a device tree node. 43 * 44 * This channel can then be passed to pwm_enable(). 45 * 46 * @param blob Device tree blob 47 * @param node Node containing reference to pwm 48 * @param prop_name Property name of pwm reference 49 * @return channel number, if ok, else -1 50 */ 51 int pwm_request(const void *blob, int node, const char *prop_name); 52 53 /** 54 * Set up the pwm controller, by looking it up in the fdt. 55 * 56 * @return 0 if ok, -1 if the device tree node was not found or invalid. 57 */ 58 int pwm_init(const void *blob); 59 60 #endif /* __ASM_ARCH_TEGRA_PWM_H */ 61