2 * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org>
4 * Derived from pl01x code:
7 * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
11 * Philippe Robin, <philippe.robin@arm.com>
13 * SPDX-License-Identifier: GPL-2.0+
16 /* Simple U-Boot driver for the BCM283x mini UART */
24 #include <dm/platform_data/serial_bcm283x_mu.h>
25 #include <linux/compiler.h>
27 struct bcm283x_mu_regs {
41 #define BCM283X_MU_LCR_DATA_SIZE_8 3
43 #define BCM283X_MU_LSR_TX_IDLE BIT(6)
44 /* This actually means not full, but is named not empty in the docs */
45 #define BCM283X_MU_LSR_TX_EMPTY BIT(5)
46 #define BCM283X_MU_LSR_RX_READY BIT(0)
48 struct bcm283x_mu_priv {
49 struct bcm283x_mu_regs *regs;
52 static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
54 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
55 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
56 struct bcm283x_mu_regs *regs = priv->regs;
62 divider = plat->clock / (baudrate * 8);
64 writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr);
65 writel(divider - 1, ®s->baud);
70 static int bcm283x_mu_serial_probe(struct udevice *dev)
72 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
73 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
75 priv->regs = (struct bcm283x_mu_regs *)plat->base;
80 static int bcm283x_mu_serial_getc(struct udevice *dev)
82 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
83 struct bcm283x_mu_regs *regs = priv->regs;
86 /* Wait until there is data in the FIFO */
87 if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY))
90 data = readl(®s->io);
95 static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
97 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
98 struct bcm283x_mu_regs *regs = priv->regs;
100 /* Wait until there is space in the FIFO */
101 if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY))
104 /* Send the character */
105 writel(data, ®s->io);
110 static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
112 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
113 struct bcm283x_mu_regs *regs = priv->regs;
116 lsr = readl(®s->lsr);
120 return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0;
122 return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1;
126 static const struct dm_serial_ops bcm283x_mu_serial_ops = {
127 .putc = bcm283x_mu_serial_putc,
128 .pending = bcm283x_mu_serial_pending,
129 .getc = bcm283x_mu_serial_getc,
130 .setbrg = bcm283x_mu_serial_setbrg,
133 #if CONFIG_IS_ENABLED(OF_CONTROL)
134 static const struct udevice_id bcm283x_mu_serial_id[] = {
135 {.compatible = "brcm,bcm2835-aux-uart"},
139 static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev)
141 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
144 addr = devfdt_get_addr(dev);
145 if (addr == FDT_ADDR_T_NONE)
149 plat->clock = dev_read_u32_default(dev, "clock", 1);
150 plat->skip_init = dev_read_bool(dev, "skip-init");
156 U_BOOT_DRIVER(serial_bcm283x_mu) = {
157 .name = "serial_bcm283x_mu",
159 .of_match = of_match_ptr(bcm283x_mu_serial_id),
160 .ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata),
161 .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
162 .probe = bcm283x_mu_serial_probe,
163 .ops = &bcm283x_mu_serial_ops,
164 .flags = DM_FLAG_PRE_RELOC,
165 .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),