/*
   * Emma Mobile EV2 clock framework support
   *
   * Copyright (C) 2012  Magnus Damm
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; version 2 of the License.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/io.h>
  #include <linux/sh_clk.h>
  #include <linux/clkdev.h>
  #include <mach/common.h>
  
  #define EMEV2_SMU_BASE 0xe0110000
  
  /* EMEV2 SMU registers */
  #define USIAU0_RSTCTRL 0x094
  #define USIBU1_RSTCTRL 0x0ac
  #define USIBU2_RSTCTRL 0x0b0
  #define USIBU3_RSTCTRL 0x0b4
  #define STI_RSTCTRL 0x124
  #define USIAU0GCLKCTRL 0x4a0
  #define USIBU1GCLKCTRL 0x4b8
  #define USIBU2GCLKCTRL 0x4bc
  #define USIBU3GCLKCTRL 0x04c0
  #define STIGCLKCTRL 0x528
  #define USIAU0SCLKDIV 0x61c
  #define USIB2SCLKDIV 0x65c
  #define USIB3SCLKDIV 0x660
  #define STI_CLKSEL 0x688
  
  /* not pretty, but hey */
  static void __iomem *smu_base;
  
  static void emev2_smu_write(unsigned long value, int offs)
  {
  	BUG_ON(!smu_base || (offs >= PAGE_SIZE));
  	iowrite32(value, smu_base + offs);
  }
  
  static struct clk_mapping smu_mapping = {
  	.phys	= EMEV2_SMU_BASE,
  	.len	= PAGE_SIZE,
  };
  
  /* Fixed 32 KHz root clock from C32K pin */
  static struct clk c32k_clk = {
  	.rate           = 32768,
  	.mapping	= &smu_mapping,
  };
  
  /* PLL3 multiplies C32K with 7000 */
  static unsigned long pll3_recalc(struct clk *clk)
  {
  	return clk->parent->rate * 7000;
  }
  
  static struct sh_clk_ops pll3_clk_ops = {
  	.recalc		= pll3_recalc,
  };
  
  static struct clk pll3_clk = {
  	.ops		= &pll3_clk_ops,
  	.parent		= &c32k_clk,
  };
  
  static struct clk *main_clks[] = {
  	&c32k_clk,
  	&pll3_clk,
  };
  
  enum { SCLKDIV_USIAU0, SCLKDIV_USIBU2, SCLKDIV_USIBU1, SCLKDIV_USIBU3,
  	SCLKDIV_NR };
  
  #define SCLKDIV(_reg, _shift)			\
  {								\
  	.parent		= &pll3_clk,				\
  	.enable_reg	= IOMEM(EMEV2_SMU_BASE + (_reg)),	\
  	.enable_bit	= _shift,				\
  }
  
  static struct clk sclkdiv_clks[SCLKDIV_NR] = {
  	[SCLKDIV_USIAU0] = SCLKDIV(USIAU0SCLKDIV, 0),
  	[SCLKDIV_USIBU2] = SCLKDIV(USIB2SCLKDIV, 16),
  	[SCLKDIV_USIBU1] = SCLKDIV(USIB2SCLKDIV, 0),
  	[SCLKDIV_USIBU3] = SCLKDIV(USIB3SCLKDIV, 0),
  };
  
  enum { GCLK_USIAU0_SCLK, GCLK_USIBU1_SCLK, GCLK_USIBU2_SCLK, GCLK_USIBU3_SCLK,
  	GCLK_STI_SCLK,
  	GCLK_NR };
  
  #define GCLK_SCLK(_parent, _reg) \
  {								\
  	.parent		= _parent,				\
  	.enable_reg	= IOMEM(EMEV2_SMU_BASE + (_reg)),	\
  	.enable_bit	= 1, /* SCLK_GCC */			\
  }
  
  static struct clk gclk_clks[GCLK_NR] = {
  	[GCLK_USIAU0_SCLK] = GCLK_SCLK(&sclkdiv_clks[SCLKDIV_USIAU0],
  				       USIAU0GCLKCTRL),
  	[GCLK_USIBU1_SCLK] = GCLK_SCLK(&sclkdiv_clks[SCLKDIV_USIBU1],
  				       USIBU1GCLKCTRL),
  	[GCLK_USIBU2_SCLK] = GCLK_SCLK(&sclkdiv_clks[SCLKDIV_USIBU2],
  				       USIBU2GCLKCTRL),
  	[GCLK_USIBU3_SCLK] = GCLK_SCLK(&sclkdiv_clks[SCLKDIV_USIBU3],
  				       USIBU3GCLKCTRL),
  	[GCLK_STI_SCLK] = GCLK_SCLK(&c32k_clk, STIGCLKCTRL),
  };
  
  static int emev2_gclk_enable(struct clk *clk)
  {
  	iowrite32(ioread32(clk->mapped_reg) | (1 << clk->enable_bit),
  		  clk->mapped_reg);
  	return 0;
  }
  
  static void emev2_gclk_disable(struct clk *clk)
  {
  	iowrite32(ioread32(clk->mapped_reg) & ~(1 << clk->enable_bit),
  		  clk->mapped_reg);
  }
  
  static struct sh_clk_ops emev2_gclk_clk_ops = {
  	.enable		= emev2_gclk_enable,
  	.disable	= emev2_gclk_disable,
  	.recalc		= followparent_recalc,
  };
  
  static int __init emev2_gclk_register(struct clk *clks, int nr)
  {
  	struct clk *clkp;
  	int ret = 0;
  	int k;
  
  	for (k = 0; !ret && (k < nr); k++) {
  		clkp = clks + k;
  		clkp->ops = &emev2_gclk_clk_ops;
  		ret |= clk_register(clkp);
  	}
  
  	return ret;
  }
  
  static unsigned long emev2_sclkdiv_recalc(struct clk *clk)
  {
  	unsigned int sclk_div;
  
  	sclk_div = (ioread32(clk->mapped_reg) >> clk->enable_bit) & 0xff;
  
  	return clk->parent->rate / (sclk_div + 1);
  }
  
  static struct sh_clk_ops emev2_sclkdiv_clk_ops = {
  	.recalc		= emev2_sclkdiv_recalc,
  };
  
  static int __init emev2_sclkdiv_register(struct clk *clks, int nr)
  {
  	struct clk *clkp;
  	int ret = 0;
  	int k;
  
  	for (k = 0; !ret && (k < nr); k++) {
  		clkp = clks + k;
  		clkp->ops = &emev2_sclkdiv_clk_ops;
  		ret |= clk_register(clkp);
  	}
  
  	return ret;
  }
  
  static struct clk_lookup lookups[] = {
  	CLKDEV_DEV_ID("serial8250-em.0", &gclk_clks[GCLK_USIAU0_SCLK]),
  	CLKDEV_DEV_ID("e1020000.uart", &gclk_clks[GCLK_USIAU0_SCLK]),
  	CLKDEV_DEV_ID("serial8250-em.1", &gclk_clks[GCLK_USIBU1_SCLK]),
  	CLKDEV_DEV_ID("e1030000.uart", &gclk_clks[GCLK_USIBU1_SCLK]),
  	CLKDEV_DEV_ID("serial8250-em.2", &gclk_clks[GCLK_USIBU2_SCLK]),
  	CLKDEV_DEV_ID("e1040000.uart", &gclk_clks[GCLK_USIBU2_SCLK]),
  	CLKDEV_DEV_ID("serial8250-em.3", &gclk_clks[GCLK_USIBU3_SCLK]),
  	CLKDEV_DEV_ID("e1050000.uart", &gclk_clks[GCLK_USIBU3_SCLK]),
  	CLKDEV_DEV_ID("em_sti.0", &gclk_clks[GCLK_STI_SCLK]),
  	CLKDEV_DEV_ID("e0180000.sti", &gclk_clks[GCLK_STI_SCLK]),
  };
  
  void __init emev2_clock_init(void)
  {
  	int k, ret = 0;
  
  	smu_base = ioremap(EMEV2_SMU_BASE, PAGE_SIZE);
  	BUG_ON(!smu_base);
  
  	/* setup STI timer to run on 32.768 kHz and deassert reset */
  	emev2_smu_write(0, STI_CLKSEL);
  	emev2_smu_write(1, STI_RSTCTRL);
  
  	/* deassert reset for UART0->UART3 */
  	emev2_smu_write(2, USIAU0_RSTCTRL);
  	emev2_smu_write(2, USIBU1_RSTCTRL);
  	emev2_smu_write(2, USIBU2_RSTCTRL);
  	emev2_smu_write(2, USIBU3_RSTCTRL);
  
  	for (k = 0; !ret && (k < ARRAY_SIZE(main_clks)); k++)
  		ret = clk_register(main_clks[k]);
  
  	if (!ret)
  		ret = emev2_sclkdiv_register(sclkdiv_clks, SCLKDIV_NR);
  
  	if (!ret)
  		ret = emev2_gclk_register(gclk_clks, GCLK_NR);
  
  	clkdev_add_table(lookups, ARRAY_SIZE(lookups));
  
  	if (!ret)
  		shmobile_clk_init();
  	else
  		panic("failed to setup emev2 clocks
  ");
  }