diff options
Diffstat (limited to 'drivers/gpu/drm/loongson/lsdc_i2c.c')
| -rw-r--r-- | drivers/gpu/drm/loongson/lsdc_i2c.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/gpu/drm/loongson/lsdc_i2c.c b/drivers/gpu/drm/loongson/lsdc_i2c.c new file mode 100644 index 000000000000..9625d0b1d0b4 --- /dev/null +++ b/drivers/gpu/drm/loongson/lsdc_i2c.c @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2023 Loongson Technology Corporation Limited + */ + +#include <drm/drm_managed.h> + +#include "lsdc_drv.h" +#include "lsdc_output.h" + +/* + * __lsdc_gpio_i2c_set - set the state of a gpio pin indicated by mask + * @mask: gpio pin mask + * @state: "0" for low, "1" for high + */ +static void __lsdc_gpio_i2c_set(struct lsdc_i2c * const li2c, int mask, int state) +{ + struct lsdc_device *ldev = to_lsdc(li2c->ddev); + unsigned long flags; + u8 val; + + spin_lock_irqsave(&ldev->reglock, flags); + + if (state) { + /* + * Setting this pin as input directly, write 1 for input. + * The external pull-up resistor will pull the level up + */ + val = readb(li2c->dir_reg); + val |= mask; + writeb(val, li2c->dir_reg); + } else { + /* First set this pin as output, write 0 for output */ + val = readb(li2c->dir_reg); + val &= ~mask; + writeb(val, li2c->dir_reg); + + /* Then, make this pin output 0 */ + val = readb(li2c->dat_reg); + val &= ~mask; + writeb(val, li2c->dat_reg); + } + + spin_unlock_irqrestore(&ldev->reglock, flags); +} + +/* + * __lsdc_gpio_i2c_get - read value back from the gpio pin indicated by mask + * @mask: gpio pin mask + * return "0" for low, "1" for high + */ +static int __lsdc_gpio_i2c_get(struct lsdc_i2c * const li2c, int mask) +{ + struct lsdc_device *ldev = to_lsdc(li2c->ddev); + unsigned long flags; + u8 val; + + spin_lock_irqsave(&ldev->reglock, flags); + + /* First set this pin as input */ + val = readb(li2c->dir_reg); + val |= mask; + writeb(val, li2c->dir_reg); + + /* Then get level state from this pin */ + val = readb(li2c->dat_reg); + + spin_unlock_irqrestore(&ldev->reglock, flags); + + return (val & mask) ? 1 : 0; +} + +static void lsdc_gpio_i2c_set_sda(void *i2c, int state) +{ + struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c; + /* set state on the li2c->sda pin */ + return __lsdc_gpio_i2c_set(li2c, li2c->sda, state); +} + +static void lsdc_gpio_i2c_set_scl(void *i2c, int state) +{ + struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c; + /* set state on the li2c->scl pin */ + return __lsdc_gpio_i2c_set(li2c, li2c->scl, state); +} + +static int lsdc_gpio_i2c_get_sda(void *i2c) +{ + struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c; + /* read value from the li2c->sda pin */ + return __lsdc_gpio_i2c_get(li2c, li2c->sda); +} + +static int lsdc_gpio_i2c_get_scl(void *i2c) +{ + struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c; + /* read the value from the li2c->scl pin */ + return __lsdc_gpio_i2c_get(li2c, li2c->scl); +} + +static void lsdc_destroy_i2c(struct drm_device *ddev, void *data) +{ + struct lsdc_i2c *li2c = (struct lsdc_i2c *)data; + + if (li2c) { + i2c_del_adapter(&li2c->adapter); + kfree(li2c); + } +} + +/* + * The DC in ls7a1000/ls7a2000/ls2k2000 has builtin gpio hardware + * + * @reg_base: gpio reg base + * @index: output channel index, 0 for PIPE0, 1 for PIPE1 + */ +int lsdc_create_i2c_chan(struct drm_device *ddev, + struct lsdc_display_pipe *dispipe, + unsigned int index) +{ + struct lsdc_device *ldev = to_lsdc(ddev); + struct i2c_adapter *adapter; + struct lsdc_i2c *li2c; + int ret; + + li2c = kzalloc(sizeof(*li2c), GFP_KERNEL); + if (!li2c) + return -ENOMEM; + + dispipe->li2c = li2c; + + if (index == 0) { + li2c->sda = 0x01; /* pin 0 */ + li2c->scl = 0x02; /* pin 1 */ + } else if (index == 1) { + li2c->sda = 0x04; /* pin 2 */ + li2c->scl = 0x08; /* pin 3 */ + } else { + return -ENOENT; + } + + li2c->ddev = ddev; + li2c->dir_reg = ldev->reg_base + LS7A_DC_GPIO_DIR_REG; + li2c->dat_reg = ldev->reg_base + LS7A_DC_GPIO_DAT_REG; + + li2c->bit.setsda = lsdc_gpio_i2c_set_sda; + li2c->bit.setscl = lsdc_gpio_i2c_set_scl; + li2c->bit.getsda = lsdc_gpio_i2c_get_sda; + li2c->bit.getscl = lsdc_gpio_i2c_get_scl; + li2c->bit.udelay = 5; + li2c->bit.timeout = usecs_to_jiffies(2200); + li2c->bit.data = li2c; + + adapter = &li2c->adapter; + adapter->algo_data = &li2c->bit; + adapter->owner = THIS_MODULE; + adapter->class = I2C_CLASS_DDC; + adapter->dev.parent = ddev->dev; + adapter->nr = -1; + + snprintf(adapter->name, sizeof(adapter->name), "lsdc-i2c%u", index); + + i2c_set_adapdata(adapter, li2c); + + ret = i2c_bit_add_bus(adapter); + if (ret) { + kfree(li2c); + return ret; + } + + ret = drmm_add_action_or_reset(ddev, lsdc_destroy_i2c, li2c); + if (ret) + return ret; + + drm_info(ddev, "%s(sda pin mask=%u, scl pin mask=%u) created\n", + adapter->name, li2c->sda, li2c->scl); + + return 0; +} |