1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Analog Devices ADP5585 PWM driver 4 * 5 * Copyright 2022 NXP 6 * Copyright 2024 Ideas on Board Oy 7 * 8 * Limitations: 9 * - The .apply() operation executes atomically, but may not wait for the 10 * period to complete (this is not documented and would need to be tested). 11 * - Disabling the PWM drives the output pin to a low level immediately. 12 * - The hardware can only generate normal polarity output. 13 */ 14 15 #include <asm/byteorder.h> 16 17 #include <linux/device.h> 18 #include <linux/err.h> 19 #include <linux/math64.h> 20 #include <linux/mfd/adp5585.h> 21 #include <linux/minmax.h> 22 #include <linux/module.h> 23 #include <linux/platform_device.h> 24 #include <linux/pwm.h> 25 #include <linux/regmap.h> 26 #include <linux/time.h> 27 #include <linux/types.h> 28 29 #define ADP5585_PWM_CHAN_NUM 1 30 31 #define ADP5585_PWM_OSC_FREQ_HZ 1000000U 32 #define ADP5585_PWM_MIN_PERIOD_NS (2ULL * NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ) 33 #define ADP5585_PWM_MAX_PERIOD_NS (2ULL * 0xffff * NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ) 34 35 static int pwm_adp5585_request(struct pwm_chip *chip, struct pwm_device *pwm) 36 { 37 struct regmap *regmap = pwmchip_get_drvdata(chip); 38 39 /* Configure the R3 pin as PWM output. */ 40 return regmap_update_bits(regmap, ADP5585_PIN_CONFIG_C, 41 ADP5585_R3_EXTEND_CFG_MASK, 42 ADP5585_R3_EXTEND_CFG_PWM_OUT); 43 } 44 45 static void pwm_adp5585_free(struct pwm_chip *chip, struct pwm_device *pwm) 46 { 47 struct regmap *regmap = pwmchip_get_drvdata(chip); 48 49 regmap_update_bits(regmap, ADP5585_PIN_CONFIG_C, 50 ADP5585_R3_EXTEND_CFG_MASK, 51 ADP5585_R3_EXTEND_CFG_GPIO4); 52 } 53 54 static int pwm_adp5585_apply(struct pwm_chip *chip, 55 struct pwm_device *pwm, 56 const struct pwm_state *state) 57 { 58 struct regmap *regmap = pwmchip_get_drvdata(chip); 59 u64 period, duty_cycle; 60 u32 on, off; 61 __le16 val; 62 int ret; 63 64 if (!state->enabled) { 65 regmap_clear_bits(regmap, ADP5585_GENERAL_CFG, ADP5585_OSC_EN); 66 regmap_clear_bits(regmap, ADP5585_PWM_CFG, ADP5585_PWM_EN); 67 return 0; 68 } 69 70 if (state->polarity != PWM_POLARITY_NORMAL) 71 return -EINVAL; 72 73 if (state->period < ADP5585_PWM_MIN_PERIOD_NS) 74 return -EINVAL; 75 76 period = min(state->period, ADP5585_PWM_MAX_PERIOD_NS); 77 duty_cycle = min(state->duty_cycle, period); 78 79 /* 80 * Compute the on and off time. As the internal oscillator frequency is 81 * 1MHz, the calculation can be simplified without loss of precision. 82 */ 83 on = div_u64(duty_cycle, NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ); 84 off = div_u64(period, NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ) - on; 85 86 val = cpu_to_le16(off); 87 ret = regmap_bulk_write(regmap, ADP5585_PWM_OFFT_LOW, &val, 2); 88 if (ret) 89 return ret; 90 91 val = cpu_to_le16(on); 92 ret = regmap_bulk_write(regmap, ADP5585_PWM_ONT_LOW, &val, 2); 93 if (ret) 94 return ret; 95 96 /* Enable PWM in continuous mode and no external AND'ing. */ 97 ret = regmap_update_bits(regmap, ADP5585_PWM_CFG, 98 ADP5585_PWM_IN_AND | ADP5585_PWM_MODE | 99 ADP5585_PWM_EN, ADP5585_PWM_EN); 100 if (ret) 101 return ret; 102 103 ret = regmap_set_bits(regmap, ADP5585_GENERAL_CFG, ADP5585_OSC_EN); 104 if (ret) 105 return ret; 106 107 return regmap_set_bits(regmap, ADP5585_PWM_CFG, ADP5585_PWM_EN); 108 } 109 110 static int pwm_adp5585_get_state(struct pwm_chip *chip, 111 struct pwm_device *pwm, 112 struct pwm_state *state) 113 { 114 struct regmap *regmap = pwmchip_get_drvdata(chip); 115 unsigned int on, off; 116 unsigned int val; 117 __le16 on_off; 118 int ret; 119 120 ret = regmap_bulk_read(regmap, ADP5585_PWM_OFFT_LOW, &on_off, 2); 121 if (ret) 122 return ret; 123 off = le16_to_cpu(on_off); 124 125 ret = regmap_bulk_read(regmap, ADP5585_PWM_ONT_LOW, &on_off, 2); 126 if (ret) 127 return ret; 128 on = le16_to_cpu(on_off); 129 130 state->duty_cycle = on * (NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ); 131 state->period = (on + off) * (NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ); 132 133 state->polarity = PWM_POLARITY_NORMAL; 134 135 regmap_read(regmap, ADP5585_PWM_CFG, &val); 136 state->enabled = !!(val & ADP5585_PWM_EN); 137 138 return 0; 139 } 140 141 static const struct pwm_ops adp5585_pwm_ops = { 142 .request = pwm_adp5585_request, 143 .free = pwm_adp5585_free, 144 .apply = pwm_adp5585_apply, 145 .get_state = pwm_adp5585_get_state, 146 }; 147 148 static int adp5585_pwm_probe(struct platform_device *pdev) 149 { 150 struct device *dev = &pdev->dev; 151 struct adp5585_dev *adp5585 = dev_get_drvdata(dev->parent); 152 struct pwm_chip *chip; 153 int ret; 154 155 chip = devm_pwmchip_alloc(dev, ADP5585_PWM_CHAN_NUM, 0); 156 if (IS_ERR(chip)) 157 return PTR_ERR(chip); 158 159 device_set_of_node_from_dev(dev, dev->parent); 160 161 pwmchip_set_drvdata(chip, adp5585->regmap); 162 chip->ops = &adp5585_pwm_ops; 163 164 ret = devm_pwmchip_add(dev, chip); 165 if (ret) 166 return dev_err_probe(dev, ret, "failed to add PWM chip\n"); 167 168 return 0; 169 } 170 171 static const struct platform_device_id adp5585_pwm_id_table[] = { 172 { "adp5585-pwm" }, 173 { /* Sentinel */ } 174 }; 175 MODULE_DEVICE_TABLE(platform, adp5585_pwm_id_table); 176 177 static struct platform_driver adp5585_pwm_driver = { 178 .driver = { 179 .name = "adp5585-pwm", 180 }, 181 .probe = adp5585_pwm_probe, 182 .id_table = adp5585_pwm_id_table, 183 }; 184 module_platform_driver(adp5585_pwm_driver); 185 186 MODULE_AUTHOR("Xiaoning Wang <xiaoning.wang@nxp.com>"); 187 MODULE_DESCRIPTION("ADP5585 PWM Driver"); 188 MODULE_LICENSE("GPL"); 189